[RFC,v3,09/12] drm: Add API for in-kernel clients

Commit Message

Noralf Trønnes Feb. 22, 2018, 8:06 p.m. UTC

This adds an API for writing in-kernel clients.

TODO:
- Flesh out and complete documentation.
- Cloned displays is not tested.
- Complete tiled display support and test it.
- Test plug/unplug different monitors.
- A runtime knob to prevent clients from attaching for debugging purposes.
- Maybe a way to unbind individual client instances.
- Maybe take the sysrq support in drm_fb_helper and move it here somehow.
- Add suspend/resume callbacks.
  Does anyone know why fbdev requires suspend/resume?

Signed-off-by: Noralf Trønnes <[e-mail]>
---
 drivers/gpu/drm/Kconfig             |    2 +
 drivers/gpu/drm/Makefile            |    3 +-
 drivers/gpu/drm/client/Kconfig      |    4 +
 drivers/gpu/drm/client/Makefile     |    1 +
 drivers/gpu/drm/client/drm_client.c | 1612 +++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_drv.c           |    6 +
 drivers/gpu/drm/drm_file.c          |    3 +
 drivers/gpu/drm/drm_probe_helper.c  |    3 +
 include/drm/drm_client.h            |  192 +++++
 include/drm/drm_device.h            |    1 +
 include/drm/drm_file.h              |    7 +
 11 files changed, 1833 insertions(+), 1 deletion(-)
 create mode 100644 drivers/gpu/drm/client/Kconfig
 create mode 100644 drivers/gpu/drm/client/Makefile
 create mode 100644 drivers/gpu/drm/client/drm_client.c
 create mode 100644 include/drm/drm_client.h

Comments

Daniel Vetter March 6, 2018, 8:56 a.m. UTC | #1

On Thu, Feb 22, 2018 at 09:06:50PM +0100, Noralf Trønnes wrote:
> This adds an API for writing in-kernel clients.
> 
> TODO:
> - Flesh out and complete documentation.
> - Cloned displays is not tested.
> - Complete tiled display support and test it.
> - Test plug/unplug different monitors.
> - A runtime knob to prevent clients from attaching for debugging purposes.
> - Maybe a way to unbind individual client instances.
> - Maybe take the sysrq support in drm_fb_helper and move it here somehow.
> - Add suspend/resume callbacks.
>   Does anyone know why fbdev requires suspend/resume?
> 
> Signed-off-by: Noralf Trønnes <[e-mail]>

The core client api I like. Some of the opens I'm seeing:

- If we go with using the internal kms api directly instead of IOCTL
  wrappers then a huge pile of the functions you have here aren't needed
  (e.g. all the event stuff we can just directly use vblank events instead
  of all the wrapping). I'm leaning ever more into that direction, since
  much less code to add.

- The register/unregister model needs more thought. Allowing both clients
  to register whenever they want to, and drm_device instances to come and
  go is what fbcon has done, and the resulting locking is a horror show.

  I think if we require that all in-kernel drm_clients are registers when
  loading drm.ko (and enabled/disabled only per module options and
  Kconfig), then we can throw out all the locking. That avoids a lot of
  the headaches.

  2nd, if the list of clients is static over the lifetime of drm.ko, we
  also don't need to iterate existing drivers. Which avoids me having to
  review the iterator patch (that's the other aspect where fbcon totally
  falls over and essentially just ignores a bunch of races).

> ---
>  drivers/gpu/drm/Kconfig             |    2 +
>  drivers/gpu/drm/Makefile            |    3 +-
>  drivers/gpu/drm/client/Kconfig      |    4 +
>  drivers/gpu/drm/client/Makefile     |    1 +
>  drivers/gpu/drm/client/drm_client.c | 1612 +++++++++++++++++++++++++++++++++++

I'd move this into main drm/ directory, it's fairly core stuff.

>  drivers/gpu/drm/drm_drv.c           |    6 +
>  drivers/gpu/drm/drm_file.c          |    3 +
>  drivers/gpu/drm/drm_probe_helper.c  |    3 +
>  include/drm/drm_client.h            |  192 +++++
>  include/drm/drm_device.h            |    1 +
>  include/drm/drm_file.h              |    7 +
>  11 files changed, 1833 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/gpu/drm/client/Kconfig
>  create mode 100644 drivers/gpu/drm/client/Makefile
>  create mode 100644 drivers/gpu/drm/client/drm_client.c
>  create mode 100644 include/drm/drm_client.h
> 
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index deeefa7a1773..d4ae15f9ee9f 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -154,6 +154,8 @@ config DRM_SCHED
>  	tristate
>  	depends on DRM
>  
> +source "drivers/gpu/drm/client/Kconfig"
> +
>  source "drivers/gpu/drm/i2c/Kconfig"
>  
>  source "drivers/gpu/drm/arm/Kconfig"
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index 50093ff4479b..8e06dc7eeca1 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -18,7 +18,7 @@ drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
>  		drm_encoder.o drm_mode_object.o drm_property.o \
>  		drm_plane.o drm_color_mgmt.o drm_print.o \
>  		drm_dumb_buffers.o drm_mode_config.o drm_vblank.o \
> -		drm_syncobj.o drm_lease.o
> +		drm_syncobj.o drm_lease.o client/drm_client.o
>  
>  drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o
>  drm-$(CONFIG_DRM_VM) += drm_vm.o
> @@ -103,3 +103,4 @@ obj-$(CONFIG_DRM_MXSFB)	+= mxsfb/
>  obj-$(CONFIG_DRM_TINYDRM) += tinydrm/
>  obj-$(CONFIG_DRM_PL111) += pl111/
>  obj-$(CONFIG_DRM_TVE200) += tve200/
> +obj-y			+= client/
> diff --git a/drivers/gpu/drm/client/Kconfig b/drivers/gpu/drm/client/Kconfig
> new file mode 100644
> index 000000000000..4bb8e4655ff7
> --- /dev/null
> +++ b/drivers/gpu/drm/client/Kconfig
> @@ -0,0 +1,4 @@
> +menu "DRM Clients"
> +	depends on DRM
> +
> +endmenu
> diff --git a/drivers/gpu/drm/client/Makefile b/drivers/gpu/drm/client/Makefile
> new file mode 100644
> index 000000000000..f66554cd5c45
> --- /dev/null
> +++ b/drivers/gpu/drm/client/Makefile
> @@ -0,0 +1 @@
> +# SPDX-License-Identifier: GPL-2.0
> diff --git a/drivers/gpu/drm/client/drm_client.c b/drivers/gpu/drm/client/drm_client.c
> new file mode 100644
> index 000000000000..a633bf747316
> --- /dev/null
> +++ b/drivers/gpu/drm/client/drm_client.c
> @@ -0,0 +1,1612 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright 2018 Noralf Trønnes
> +
> +#include <linux/dma-buf.h>
> +#include <linux/list.h>
> +#include <linux/mutex.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +
> +#include <drm/drm_client.h>
> +#include <drm/drm_connector.h>
> +#include <drm/drm_drv.h>
> +#include <drm/drm_file.h>
> +#include <drm/drm_ioctl.h>
> +#include <drm/drmP.h>
> +
> +#include "drm_crtc_internal.h"
> +#include "drm_internal.h"
> +
> +struct drm_client_funcs_entry {
> +	struct list_head list;
> +	const struct drm_client_funcs *funcs;
> +};
> +
> +static LIST_HEAD(drm_client_list);

I think the client list itself should be on the drm_device, not in one
global list that mixes up all the clients of all the drm_devices.

I'll skip reviewing details since we have a bunch of high-level questions
to figure out first.
-Daniel

> +static LIST_HEAD(drm_client_funcs_list);
> +static DEFINE_MUTEX(drm_client_list_lock);
> +
> +static void drm_client_new(struct drm_device *dev,
> +			   const struct drm_client_funcs *funcs)
> +{
> +	struct drm_client_dev *client;
> +	int ret;
> +
> +	lockdep_assert_held(&drm_client_list_lock);
> +
> +	client = kzalloc(sizeof(*client), GFP_KERNEL);
> +	if (!client)
> +		return;
> +
> +	mutex_init(&client->lock);
> +	client->dev = dev;
> +	client->funcs = funcs;
> +
> +	ret = funcs->new(client);
> +	DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n", funcs->name, ret);
> +	if (ret) {
> +		drm_client_free(client);
> +		return;
> +	}
> +
> +	list_add(&client->list, &drm_client_list);
> +}
> +
> +/**
> + * drm_client_free - Free DRM client resources
> + * @client: DRM client
> + *
> + * This is called automatically on client removal unless the client returns
> + * non-zero in the &drm_client_funcs->remove callback. The fbdev client does
> + * this when it can't close &drm_file because userspace has an open fd.
> + */
> +void drm_client_free(struct drm_client_dev *client)
> +{
> +	DRM_DEV_DEBUG_KMS(client->dev->dev, "%s\n", client->funcs->name);
> +	if (WARN_ON(client->file)) {
> +		client->file_ref_count = 1;
> +		drm_client_put_file(client);
> +	}
> +	mutex_destroy(&client->lock);
> +	kfree(client->crtcs);
> +	kfree(client);
> +}
> +EXPORT_SYMBOL(drm_client_free);
> +
> +static void drm_client_remove(struct drm_client_dev *client)
> +{
> +	lockdep_assert_held(&drm_client_list_lock);
> +
> +	list_del(&client->list);
> +
> +	if (!client->funcs->remove || !client->funcs->remove(client))
> +		drm_client_free(client);
> +}
> +
> +/**
> + * drm_client_register - Register a DRM client
> + * @funcs: Client callbacks
> + *
> + * Returns:
> + * Zero on success, negative error code on failure.
> + */
> +int drm_client_register(const struct drm_client_funcs *funcs)
> +{
> +	struct drm_client_funcs_entry *funcs_entry;
> +	struct drm_device_list_iter iter;
> +	struct drm_device *dev;
> +
> +	funcs_entry = kzalloc(sizeof(*funcs_entry), GFP_KERNEL);
> +	if (!funcs_entry)
> +		return -ENOMEM;
> +
> +	funcs_entry->funcs = funcs;
> +
> +	mutex_lock(&drm_global_mutex);
> +	mutex_lock(&drm_client_list_lock);
> +
> +	drm_device_list_iter_begin(&iter);
> +	drm_for_each_device_iter(dev, &iter)
> +		if (drm_core_check_feature(dev, DRIVER_MODESET))
> +			drm_client_new(dev, funcs);
> +	drm_device_list_iter_end(&iter);
> +
> +	list_add(&funcs_entry->list, &drm_client_funcs_list);
> +
> +	mutex_unlock(&drm_client_list_lock);
> +	mutex_unlock(&drm_global_mutex);
> +
> +	DRM_DEBUG_KMS("%s\n", funcs->name);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_client_register);
> +
> +/**
> + * drm_client_unregister - Unregister a DRM client
> + * @funcs: Client callbacks
> + */
> +void drm_client_unregister(const struct drm_client_funcs *funcs)
> +{
> +	struct drm_client_funcs_entry *funcs_entry;
> +	struct drm_client_dev *client, *tmp;
> +
> +	mutex_lock(&drm_client_list_lock);
> +
> +	list_for_each_entry_safe(client, tmp, &drm_client_list, list) {
> +		if (client->funcs == funcs)
> +			drm_client_remove(client);
> +	}
> +
> +	list_for_each_entry(funcs_entry, &drm_client_funcs_list, list) {
> +		if (funcs_entry->funcs == funcs) {
> +			list_del(&funcs_entry->list);
> +			kfree(funcs_entry);
> +			break;
> +		}
> +	}
> +
> +	mutex_unlock(&drm_client_list_lock);
> +
> +	DRM_DEBUG_KMS("%s\n", funcs->name);
> +}
> +EXPORT_SYMBOL(drm_client_unregister);
> +
> +void drm_client_dev_register(struct drm_device *dev)
> +{
> +	struct drm_client_funcs_entry *funcs_entry;
> +
> +	/*
> +	 * Minors are created at the beginning of drm_dev_register(), but can
> +	 * be removed again if the function fails. Since we iterate DRM devices
> +	 * by walking DRM minors, we need to stay under this lock.
> +	 */
> +	lockdep_assert_held(&drm_global_mutex);
> +
> +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
> +		return;
> +
> +	mutex_lock(&drm_client_list_lock);
> +	list_for_each_entry(funcs_entry, &drm_client_funcs_list, list)
> +		drm_client_new(dev, funcs_entry->funcs);
> +	mutex_unlock(&drm_client_list_lock);
> +}
> +
> +void drm_client_dev_unregister(struct drm_device *dev)
> +{
> +	struct drm_client_dev *client, *tmp;
> +
> +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
> +		return;
> +
> +	mutex_lock(&drm_client_list_lock);
> +	list_for_each_entry_safe(client, tmp, &drm_client_list, list)
> +		if (client->dev == dev)
> +			drm_client_remove(client);
> +	mutex_unlock(&drm_client_list_lock);
> +}
> +
> +void drm_client_dev_hotplug(struct drm_device *dev)
> +{
> +	struct drm_client_dev *client;
> +	int ret;
> +
> +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
> +		return;
> +
> +	mutex_lock(&drm_client_list_lock);
> +	list_for_each_entry(client, &drm_client_list, list)
> +		if (client->dev == dev && client->funcs->hotplug) {
> +			ret = client->funcs->hotplug(client);
> +			DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n",
> +					  client->funcs->name, ret);
> +		}
> +	mutex_unlock(&drm_client_list_lock);
> +}
> +
> +void drm_client_dev_lastclose(struct drm_device *dev)
> +{
> +	struct drm_client_dev *client;
> +	int ret;
> +
> +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
> +		return;
> +
> +	mutex_lock(&drm_client_list_lock);
> +	list_for_each_entry(client, &drm_client_list, list)
> +		if (client->dev == dev && client->funcs->lastclose) {
> +			ret = client->funcs->lastclose(client);
> +			DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n",
> +					  client->funcs->name, ret);
> +		}
> +	mutex_unlock(&drm_client_list_lock);
> +}
> +
> +/* Get static info */
> +static int drm_client_init(struct drm_client_dev *client, struct drm_file *file)
> +{
> +	struct drm_mode_card_res card_res = {};
> +	struct drm_device *dev = client->dev;
> +	u32 *crtcs;
> +	int ret;
> +
> +	ret = drm_mode_getresources(dev, &card_res, file, false);
> +	if (ret)
> +		return ret;
> +	if (!card_res.count_crtcs)
> +		return -ENOENT;
> +
> +	crtcs = kmalloc_array(card_res.count_crtcs, sizeof(*crtcs), GFP_KERNEL);
> +	if (!crtcs)
> +		return -ENOMEM;
> +
> +	card_res.count_fbs = 0;
> +	card_res.count_connectors = 0;
> +	card_res.count_encoders = 0;
> +	card_res.crtc_id_ptr = (unsigned long)crtcs;
> +
> +	ret = drm_mode_getresources(dev, &card_res, file, false);
> +	if (ret) {
> +		kfree(crtcs);
> +		return ret;
> +	}
> +
> +	client->crtcs = crtcs;
> +	client->num_crtcs = card_res.count_crtcs;
> +	client->min_width = card_res.min_width;
> +	client->max_width = card_res.max_width;
> +	client->min_height = card_res.min_height;
> +	client->max_height = card_res.max_height;
> +
> +	return 0;
> +}
> +
> +/**
> + * drm_client_get_file - Get a DRM file
> + * @client: DRM client
> + *
> + * This function makes sure the client has a &drm_file available. The client
> + * doesn't normally need to call this, since all client functions that depends
> + * on a DRM file will call it. A matching call to drm_client_put_file() is
> + * necessary.
> + *
> + * The reason for not opening a DRM file when a @client is created is because
> + * we have to take a ref on the driver module due to &drm_driver->postclose
> + * being called in drm_file_free(). Having a DRM file open for the lifetime of
> + * the client instance would block driver module unload.
> + *
> + * Returns:
> + * Zero on success, negative error code on failure.
> + */
> +int drm_client_get_file(struct drm_client_dev *client)
> +{
> +	struct drm_device *dev = client->dev;
> +	struct drm_file *file;
> +	int ret = 0;
> +
> +	mutex_lock(&client->lock);
> +
> +	if (client->file_ref_count++) {
> +		mutex_unlock(&client->lock);
> +		return 0;
> +	}
> +
> +	if (!try_module_get(dev->driver->fops->owner)) {
> +		ret = -ENODEV;
> +		goto err_unlock;
> +	}
> +
> +	drm_dev_get(dev);
> +
> +	file = drm_file_alloc(dev->primary);
> +	if (IS_ERR(file)) {
> +		ret = PTR_ERR(file);
> +		goto err_put;
> +	}
> +
> +	if (!client->crtcs) {
> +		ret = drm_client_init(client, file);
> +		if (ret)
> +			goto err_free;
> +	}
> +
> +	mutex_lock(&dev->filelist_mutex);
> +	list_add(&file->lhead, &dev->filelist_internal);
> +	mutex_unlock(&dev->filelist_mutex);
> +
> +	client->file = file;
> +
> +	mutex_unlock(&client->lock);
> +
> +	return 0;
> +
> +err_free:
> +	drm_file_free(file);
> +err_put:
> +	drm_dev_put(dev);
> +	module_put(dev->driver->fops->owner);
> +err_unlock:
> +	client->file_ref_count = 0;
> +	mutex_unlock(&client->lock);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL(drm_client_get_file);
> +
> +void drm_client_put_file(struct drm_client_dev *client)
> +{
> +	struct drm_device *dev = client->dev;
> +
> +	if (!client)
> +		return;
> +
> +	mutex_lock(&client->lock);
> +
> +	if (WARN_ON(!client->file_ref_count))
> +		goto out_unlock;
> +
> +	if (--client->file_ref_count)
> +		goto out_unlock;
> +
> +	mutex_lock(&dev->filelist_mutex);
> +	list_del(&client->file->lhead);
> +	mutex_unlock(&dev->filelist_mutex);
> +
> +	drm_file_free(client->file);
> +	client->file = NULL;
> +	drm_dev_put(dev);
> +	module_put(dev->driver->fops->owner);
> +out_unlock:
> +	mutex_unlock(&client->lock);
> +}
> +EXPORT_SYMBOL(drm_client_put_file);
> +
> +static struct drm_pending_event *
> +drm_client_read_get_pending_event(struct drm_device *dev, struct drm_file *file)
> +{
> +	struct drm_pending_event *e = NULL;
> +	int ret;
> +
> +	ret = mutex_lock_interruptible(&file->event_read_lock);
> +	if (ret)
> +		return ERR_PTR(ret);
> +
> +	spin_lock_irq(&dev->event_lock);
> +	if (!list_empty(&file->event_list)) {
> +		e = list_first_entry(&file->event_list,
> +				     struct drm_pending_event, link);
> +		file->event_space += e->event->length;
> +		list_del(&e->link);
> +	}
> +	spin_unlock_irq(&dev->event_lock);
> +
> +	mutex_unlock(&file->event_read_lock);
> +
> +	return e;
> +}
> +
> +struct drm_event *
> +drm_client_read_event(struct drm_client_dev *client, bool block)
> +{
> +	struct drm_file *file = client->file;
> +	struct drm_device *dev = client->dev;
> +	struct drm_pending_event *e;
> +	struct drm_event *event;
> +	int ret;
> +
> +	/* Allocate so it fits all events, there's a sanity check later */
> +	event = kzalloc(128, GFP_KERNEL);
> +	if (!event)
> +		return ERR_PTR(-ENOMEM);
> +
> +	e = drm_client_read_get_pending_event(dev, file);
> +	if (IS_ERR(e)) {
> +		ret = PTR_ERR(e);
> +		goto err_free;
> +	}
> +
> +	if (!e && !block) {
> +		ret = 0;
> +		goto err_free;
> +	}
> +
> +	ret = wait_event_interruptible_timeout(file->event_wait,
> +					       !list_empty(&file->event_list),
> +					       5 * HZ);
> +	if (!ret)
> +		ret = -ETIMEDOUT;
> +	if (ret < 0)
> +		goto err_free;
> +
> +	e = drm_client_read_get_pending_event(dev, file);
> +	if (IS_ERR_OR_NULL(e)) {
> +		ret = PTR_ERR_OR_ZERO(e);
> +		goto err_free;
> +	}
> +
> +	if (WARN_ON(e->event->length > 128)) {
> +		/* Increase buffer if this happens */
> +		ret = -ENOMEM;
> +		goto err_free;
> +	}
> +
> +	memcpy(event, e->event, e->event->length);
> +	kfree(e);
> +
> +	return event;
> +
> +err_free:
> +	kfree(event);
> +
> +	return ret ? ERR_PTR(ret) : NULL;
> +}
> +EXPORT_SYMBOL(drm_client_read_event);
> +
> +static void drm_client_connector_free(struct drm_client_connector *connector)
> +{
> +	if (!connector)
> +		return;
> +	kfree(connector->modes);
> +	kfree(connector);
> +}
> +
> +static struct drm_client_connector *
> +drm_client_get_connector(struct drm_client_dev *client, unsigned int id)
> +{
> +	struct drm_mode_get_connector req = {
> +		.connector_id = id,
> +	};
> +	struct drm_client_connector *connector;
> +	struct drm_mode_modeinfo *modes = NULL;
> +	struct drm_device *dev = client->dev;
> +	struct drm_connector *conn;
> +	bool non_desktop;
> +	int ret;
> +
> +	connector = kzalloc(sizeof(*connector), GFP_KERNEL);
> +	if (!connector)
> +		return ERR_PTR(-ENOMEM);
> +
> +	ret = drm_mode_getconnector(dev, &req, client->file, false);
> +	if (ret)
> +		goto err_free;
> +
> +	connector->conn_id = id;
> +	connector->status = req.connection;
> +
> +	conn = drm_connector_lookup(dev, client->file, id);
> +	if (!conn) {
> +		ret = -ENOENT;
> +		goto err_free;
> +	}
> +
> +	non_desktop = conn->display_info.non_desktop;
> +
> +	connector->has_tile = conn->has_tile;
> +	connector->tile_h_loc = conn->tile_h_loc;
> +	connector->tile_v_loc = conn->tile_v_loc;
> +	if (conn->tile_group)
> +		connector->tile_group = conn->tile_group->id;
> +
> +	drm_connector_put(conn);
> +
> +	if (non_desktop) {
> +		kfree(connector);
> +		return NULL;
> +	}
> +
> +	if (!req.count_modes)
> +		return connector;
> +
> +	modes = kcalloc(req.count_modes, sizeof(*modes), GFP_KERNEL);
> +	if (!modes) {
> +		ret = -ENOMEM;
> +		goto err_free;
> +	}
> +
> +	connector->modes = modes;
> +	connector->num_modes = req.count_modes;
> +
> +	req.count_props = 0;
> +	req.count_encoders = 0;
> +	req.modes_ptr = (unsigned long)modes;
> +
> +	ret = drm_mode_getconnector(dev, &req, client->file, false);
> +	if (ret)
> +		goto err_free;
> +
> +	return connector;
> +
> +err_free:
> +	kfree(modes);
> +	kfree(connector);
> +
> +	return ERR_PTR(ret);
> +}
> +
> +static int drm_client_get_connectors(struct drm_client_dev *client,
> +				     struct drm_client_connector ***connectors)
> +{
> +	struct drm_mode_card_res card_res = {};
> +	struct drm_device *dev = client->dev;
> +	int ret, num_connectors;
> +	u32 *connector_ids;
> +	unsigned int i;
> +
> +	ret = drm_mode_getresources(dev, &card_res, client->file, false);
> +	if (ret)
> +		return ret;
> +	if (!card_res.count_connectors)
> +		return 0;
> +
> +	num_connectors = card_res.count_connectors;
> +	connector_ids = kcalloc(num_connectors,
> +				sizeof(*connector_ids), GFP_KERNEL);
> +	if (!connector_ids)
> +		return -ENOMEM;
> +
> +	card_res.count_fbs = 0;
> +	card_res.count_crtcs = 0;
> +	card_res.count_encoders = 0;
> +	card_res.connector_id_ptr = (unsigned long)connector_ids;
> +
> +	ret = drm_mode_getresources(dev, &card_res, client->file, false);
> +	if (ret)
> +		goto err_free;
> +
> +	*connectors = kcalloc(num_connectors, sizeof(**connectors), GFP_KERNEL);
> +	if (!(*connectors)) {
> +		ret = -ENOMEM;
> +		goto err_free;
> +	}
> +
> +	for (i = 0; i < num_connectors; i++) {
> +		struct drm_client_connector *connector;
> +
> +		connector = drm_client_get_connector(client, connector_ids[i]);
> +		if (IS_ERR(connector)) {
> +			ret = PTR_ERR(connector);
> +			goto err_free;
> +		}
> +		if (connector)
> +			(*connectors)[i] = connector;
> +		else
> +			num_connectors--;
> +	}
> +
> +	if (!num_connectors) {
> +		ret = 0;
> +		goto err_free;
> +	}
> +
> +	return num_connectors;
> +
> +err_free:
> +	if (connectors)
> +		for (i = 0; i < num_connectors; i++)
> +			drm_client_connector_free((*connectors)[i]);
> +
> +	kfree(connectors);
> +	kfree(connector_ids);
> +
> +	return ret;
> +}
> +
> +static bool
> +drm_client_connector_is_enabled(struct drm_client_connector *connector,
> +				bool strict)
> +{
> +	if (strict)
> +		return connector->status == connector_status_connected;
> +	else
> +		return connector->status != connector_status_disconnected;
> +}
> +
> +struct drm_mode_modeinfo *
> +drm_client_display_first_mode(struct drm_client_display *display)
> +{
> +	if (!display->num_modes)
> +		return NULL;
> +	return display->modes;
> +}
> +EXPORT_SYMBOL(drm_client_display_first_mode);
> +
> +struct drm_mode_modeinfo *
> +drm_client_display_next_mode(struct drm_client_display *display,
> +			     struct drm_mode_modeinfo *mode)
> +{
> +	struct drm_mode_modeinfo *modes = display->modes;
> +
> +	if (++mode < &modes[display->num_modes])
> +		return mode;
> +
> +	return NULL;
> +}
> +EXPORT_SYMBOL(drm_client_display_next_mode);
> +
> +static void
> +drm_client_display_fill_tile_modes(struct drm_client_display *display,
> +				   struct drm_mode_modeinfo *tile_modes)
> +{
> +	unsigned int i, j, num_modes = display->connectors[0]->num_modes;
> +	struct drm_mode_modeinfo *tile_mode, *conn_mode;
> +
> +	if (!num_modes) {
> +		kfree(tile_modes);
> +		kfree(display->modes);
> +		display->modes = NULL;
> +		display->num_modes = 0;
> +		return;
> +	}
> +
> +	for (i = 0; i < num_modes; i++) {
> +		tile_mode = &tile_modes[i];
> +
> +		conn_mode = &display->connectors[0]->modes[i];
> +		tile_mode->clock = conn_mode->clock;
> +		tile_mode->vscan = conn_mode->vscan;
> +		tile_mode->vrefresh = conn_mode->vrefresh;
> +		tile_mode->flags = conn_mode->flags;
> +		tile_mode->type = conn_mode->type;
> +
> +		for (j = 0; j < display->num_connectors; j++) {
> +			conn_mode = &display->connectors[j]->modes[i];
> +
> +			if (!display->connectors[j]->tile_h_loc) {
> +				tile_mode->hdisplay += conn_mode->hdisplay;
> +				tile_mode->hsync_start += conn_mode->hsync_start;
> +				tile_mode->hsync_end += conn_mode->hsync_end;
> +				tile_mode->htotal += conn_mode->htotal;
> +			}
> +
> +			if (!display->connectors[j]->tile_v_loc) {
> +				tile_mode->vdisplay += conn_mode->vdisplay;
> +				tile_mode->vsync_start += conn_mode->vsync_start;
> +				tile_mode->vsync_end += conn_mode->vsync_end;
> +				tile_mode->vtotal += conn_mode->vtotal;
> +			}
> +		}
> +	}
> +
> +	kfree(display->modes);
> +	display->modes = tile_modes;
> +	display->num_modes = num_modes;
> +}
> +
> +/**
> + * drm_client_display_update_modes - Fetch display modes
> + * @display: Client display
> + * @mode_changed: Optional pointer to boolen which return whether the modes
> + *                have changed or not.
> + *
> + * This function can be used in the client hotplug callback to check if the
> + * video modes have changed and get them up-to-date.
> + *
> + * Returns:
> + * Number of modes on success, negative error code on failure.
> + */
> +int drm_client_display_update_modes(struct drm_client_display *display,
> +				    bool *mode_changed)
> +{
> +	unsigned int num_connectors = display->num_connectors;
> +	struct drm_client_dev *client = display->client;
> +	struct drm_mode_modeinfo *display_tile_modes;
> +	struct drm_client_connector **connectors;
> +	unsigned int i, num_modes = 0;
> +	bool dummy_changed = false;
> +	int ret;
> +
> +	if (mode_changed)
> +		*mode_changed = false;
> +	else
> +		mode_changed = &dummy_changed;
> +
> +	if (display->cloned)
> +		return 2;
> +
> +	ret = drm_client_get_file(client);
> +	if (ret)
> +		return ret;
> +
> +	connectors = kcalloc(num_connectors, sizeof(*connectors), GFP_KERNEL);
> +	if (!connectors) {
> +		ret = -ENOMEM;
> +		goto out_put_file;
> +	}
> +
> +	/* Get a new set for comparison */
> +	for (i = 0; i < num_connectors; i++) {
> +		connectors[i] = drm_client_get_connector(client, display->connectors[i]->conn_id);
> +		if (IS_ERR_OR_NULL(connectors[i])) {
> +			ret = PTR_ERR_OR_ZERO(connectors[i]);
> +			if (!ret)
> +				ret = -ENOENT;
> +			goto out_cleanup;
> +		}
> +	}
> +
> +	/* All connectors should have the same number of modes */
> +	num_modes = connectors[0]->num_modes;
> +	for (i = 0; i < num_connectors; i++) {
> +		if (num_modes != connectors[i]->num_modes) {
> +			ret = -EINVAL;
> +			goto out_cleanup;
> +		}
> +	}
> +
> +	if (num_connectors > 1) {
> +		display_tile_modes = kcalloc(num_modes, sizeof(*display_tile_modes), GFP_KERNEL);
> +		if (!display_tile_modes) {
> +			ret = -ENOMEM;
> +			goto out_cleanup;
> +		}
> +	}
> +
> +	mutex_lock(&display->modes_lock);
> +
> +	for (i = 0; i < num_connectors; i++) {
> +		display->connectors[i]->status = connectors[i]->status;
> +		if (display->connectors[i]->num_modes != connectors[i]->num_modes) {
> +			display->connectors[i]->num_modes = connectors[i]->num_modes;
> +			kfree(display->connectors[i]->modes);
> +			display->connectors[i]->modes = connectors[i]->modes;
> +			connectors[i]->modes = NULL;
> +			*mode_changed = true;
> +		}
> +	}
> +
> +	if (num_connectors > 1)
> +		drm_client_display_fill_tile_modes(display, display_tile_modes);
> +	else
> +		display->modes = display->connectors[0]->modes;
> +
> +	mutex_unlock(&display->modes_lock);
> +
> +out_cleanup:
> +	for (i = 0; i < num_connectors; i++)
> +		drm_client_connector_free(connectors[i]);
> +	kfree(connectors);
> +out_put_file:
> +	drm_client_put_file(client);
> +
> +	return ret ? ret : num_modes;
> +}
> +EXPORT_SYMBOL(drm_client_display_update_modes);
> +
> +void drm_client_display_free(struct drm_client_display *display)
> +{
> +	unsigned int i;
> +
> +	if (!display)
> +		return;
> +
> +	/* tile modes? */
> +	if (display->modes != display->connectors[0]->modes)
> +		kfree(display->modes);
> +
> +	for (i = 0; i < display->num_connectors; i++)
> +		drm_client_connector_free(display->connectors[i]);
> +
> +	kfree(display->connectors);
> +	mutex_destroy(&display->modes_lock);
> +	kfree(display);
> +}
> +EXPORT_SYMBOL(drm_client_display_free);
> +
> +static struct drm_client_display *
> +drm_client_display_alloc(struct drm_client_dev *client,
> +			 unsigned int num_connectors)
> +{
> +	struct drm_client_display *display;
> +	struct drm_client_connector **connectors;
> +
> +	display = kzalloc(sizeof(*display), GFP_KERNEL);
> +	connectors = kcalloc(num_connectors, sizeof(*connectors), GFP_KERNEL);
> +	if (!display || !connectors) {
> +		kfree(display);
> +		kfree(connectors);
> +		return NULL;
> +	}
> +
> +	mutex_init(&display->modes_lock);
> +	display->client = client;
> +	display->connectors = connectors;
> +	display->num_connectors = num_connectors;
> +
> +	return display;
> +}
> +
> +/* Logic is from drm_fb_helper */
> +static struct drm_client_display *
> +drm_client_connector_pick_cloned(struct drm_client_dev *client,
> +				 struct drm_client_connector **connectors,
> +				 unsigned int num_connectors)
> +{
> +	struct drm_mode_modeinfo modes[2], udmt_mode, *mode, *tmp;
> +	struct drm_display_mode *dmt_display_mode = NULL;
> +	unsigned int i, j, conns[2], num_conns = 0;
> +	struct drm_client_connector *connector;
> +	struct drm_device *dev = client->dev;
> +	struct drm_client_display *display;
> +
> +	/* only contemplate cloning in the single crtc case */
> +	if (dev->mode_config.num_crtc > 1)
> +		return NULL;
> +retry:
> +	for (i = 0; i < num_connectors; i++) {
> +		connector = connectors[i];
> +		if (!connector || connector->has_tile || !connector->num_modes)
> +			continue;
> +
> +		for (j = 0; j < connector->num_modes; j++) {
> +			mode = &connector->modes[j];
> +			if (dmt_display_mode) {
> +				if (drm_umode_equal(&udmt_mode, mode)) {
> +					conns[num_conns] = i;
> +					modes[num_conns++] = *mode;
> +					break;
> +				}
> +			} else {
> +				if (mode->type & DRM_MODE_TYPE_USERDEF) {
> +					conns[num_conns] = i;
> +					modes[num_conns++] = *mode;
> +					break;
> +				}
> +			}
> +		}
> +		if (num_conns == 2)
> +			break;
> +	}
> +
> +	if (num_conns == 2)
> +		goto found;
> +
> +	if (dmt_display_mode)
> +		return NULL;
> +
> +	dmt_display_mode = drm_mode_find_dmt(dev, 1024, 768, 60, false);
> +	drm_mode_convert_to_umode(&udmt_mode, dmt_display_mode);
> +	drm_mode_destroy(dev, dmt_display_mode);
> +
> +	goto retry;
> +
> +found:
> +	tmp = kcalloc(2, sizeof(*tmp), GFP_KERNEL);
> +	if (!tmp)
> +		return ERR_PTR(-ENOMEM);
> +
> +	display = drm_client_display_alloc(client, 2);
> +	if (!display) {
> +		kfree(tmp);
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	for (i = 0; i < 2; i++) {
> +		connector = connectors[conns[i]];
> +		display->connectors[i] = connector;
> +		connectors[conns[i]] = NULL;
> +		kfree(connector->modes);
> +		tmp[i] = modes[i];
> +		connector->modes = &tmp[i];
> +		connector->num_modes = 1;
> +	}
> +
> +	display->cloned = true;
> +	display->modes = &tmp[0];
> +	display->num_modes = 1;
> +
> +	return display;
> +}
> +
> +static struct drm_client_display *
> +drm_client_connector_pick_tile(struct drm_client_dev *client,
> +			       struct drm_client_connector **connectors,
> +			       unsigned int num_connectors)
> +{
> +	unsigned int i, num_conns, num_modes, tile_group = 0;
> +	struct drm_mode_modeinfo *tile_modes = NULL;
> +	struct drm_client_connector *connector;
> +	struct drm_client_display *display;
> +	u16 conns[32];
> +
> +	for (i = 0; i < num_connectors; i++) {
> +		connector = connectors[i];
> +		if (!connector || !connector->tile_group)
> +			continue;
> +
> +		if (!tile_group) {
> +			tile_group = connector->tile_group;
> +			num_modes = connector->num_modes;
> +		}
> +
> +		if (connector->tile_group != tile_group)
> +			continue;
> +
> +		if (num_modes != connector->num_modes) {
> +			DRM_ERROR("Tile connectors must have the same number of modes\n");
> +			return ERR_PTR(-EINVAL);
> +		}
> +
> +		conns[num_conns++] = i;
> +		if (WARN_ON(num_conns == 33))
> +			return ERR_PTR(-EINVAL);
> +	}
> +
> +	if (!num_conns)
> +		return NULL;
> +
> +	if (num_modes) {
> +		tile_modes = kcalloc(num_modes, sizeof(*tile_modes), GFP_KERNEL);
> +		if (!tile_modes)
> +			return ERR_PTR(-ENOMEM);
> +	}
> +
> +	display = drm_client_display_alloc(client, num_conns);
> +	if (!display) {
> +		kfree(tile_modes);
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	if (num_modes)
> +		drm_client_display_fill_tile_modes(display, tile_modes);
> +
> +	return display;
> +}
> +
> +static struct drm_client_display *
> +drm_client_connector_pick_not_tile(struct drm_client_dev *client,
> +				   struct drm_client_connector **connectors,
> +				   unsigned int num_connectors)
> +{
> +	struct drm_client_display *display;
> +	unsigned int i;
> +
> +	for (i = 0; i < num_connectors; i++) {
> +		if (!connectors[i] || connectors[i]->has_tile)
> +			continue;
> +		break;
> +	}
> +
> +	if (i == num_connectors)
> +		return NULL;
> +
> +	display = drm_client_display_alloc(client, 1);
> +	if (!display)
> +		return ERR_PTR(-ENOMEM);
> +
> +	display->connectors[0] = connectors[i];
> +	connectors[i] = NULL;
> +	display->modes = display->connectors[0]->modes;
> +	display->num_modes = display->connectors[0]->num_modes;
> +
> +	return display;
> +}
> +
> +/* Get connectors and bundle them up into displays */
> +static int drm_client_get_displays(struct drm_client_dev *client,
> +				   struct drm_client_display ***displays)
> +{
> +	int ret, num_connectors, num_displays = 0;
> +	struct drm_client_connector **connectors;
> +	struct drm_client_display *display;
> +	unsigned int i;
> +
> +	ret = drm_client_get_file(client);
> +	if (ret)
> +		return ret;
> +
> +	num_connectors = drm_client_get_connectors(client, &connectors);
> +	if (num_connectors <= 0) {
> +		ret = num_connectors;
> +		goto err_put_file;
> +	}
> +
> +	*displays = kcalloc(num_connectors, sizeof(*displays), GFP_KERNEL);
> +	if (!(*displays)) {
> +		ret = -ENOMEM;
> +		goto err_free;
> +	}
> +
> +	display = drm_client_connector_pick_cloned(client, connectors,
> +						   num_connectors);
> +	if (IS_ERR(display)) {
> +		ret = PTR_ERR(display);
> +		goto err_free;
> +	}
> +	if (display)
> +		(*displays)[num_displays++] = display;
> +
> +	for (i = 0; i < num_connectors; i++) {
> +		display = drm_client_connector_pick_tile(client, connectors,
> +							 num_connectors);
> +		if (IS_ERR(display)) {
> +			ret = PTR_ERR(display);
> +			goto err_free;
> +		}
> +		if (!display)
> +			break;
> +		(*displays)[num_displays++] = display;
> +	}
> +
> +	for (i = 0; i < num_connectors; i++) {
> +		display = drm_client_connector_pick_not_tile(client, connectors,
> +							     num_connectors);
> +		if (IS_ERR(display)) {
> +			ret = PTR_ERR(display);
> +			goto err_free;
> +		}
> +		if (!display)
> +			break;
> +		(*displays)[num_displays++] = display;
> +	}
> +
> +	for (i = 0; i < num_connectors; i++) {
> +		if (connectors[i]) {
> +			DRM_INFO("Connector %u fell through the cracks.\n",
> +				 connectors[i]->conn_id);
> +			drm_client_connector_free(connectors[i]);
> +		}
> +	}
> +
> +	drm_client_put_file(client);
> +	kfree(connectors);
> +
> +	return num_displays;
> +
> +err_free:
> +	for (i = 0; i < num_displays; i++)
> +		drm_client_display_free((*displays)[i]);
> +	kfree(*displays);
> +	*displays = NULL;
> +	for (i = 0; i < num_connectors; i++)
> +		drm_client_connector_free(connectors[i]);
> +	kfree(connectors);
> +err_put_file:
> +	drm_client_put_file(client);
> +
> +	return ret;
> +}
> +
> +static bool
> +drm_client_display_is_enabled(struct drm_client_display *display, bool strict)
> +{
> +	unsigned int i;
> +
> +	if (!display->num_modes)
> +		return false;
> +
> +	for (i = 0; i < display->num_connectors; i++)
> +		if (!drm_client_connector_is_enabled(display->connectors[i], strict))
> +			return false;
> +
> +	return true;
> +}
> +
> +/**
> + * drm_client_display_get_first_enabled - Get first enabled display
> + * @client: DRM client
> + * @strict: If true the connector(s) have to be connected, if false they can
> + *          also have unknown status.
> + *
> + * This function gets all connectors and bundles them into displays
> + * (tiled/cloned). It then picks the first one with connectors that is enabled
> + * according to @strict.
> + *
> + * Returns:
> + * Pointer to a client display if such a display was found, NULL if not found
> + * or an error pointer on failure.
> + */
> +struct drm_client_display *
> +drm_client_display_get_first_enabled(struct drm_client_dev *client, bool strict)
> +{
> +	struct drm_client_display **displays, *display = NULL;
> +	int num_displays;
> +	unsigned int i;
> +
> +	num_displays = drm_client_get_displays(client, &displays);
> +	if (num_displays < 0)
> +		return ERR_PTR(num_displays);
> +	if (!num_displays)
> +		return NULL;
> +
> +	for (i = 0; i < num_displays; i++) {
> +		if (!display &&
> +		    drm_client_display_is_enabled(displays[i], strict)) {
> +			display = displays[i];
> +			continue;
> +		}
> +		drm_client_display_free(displays[i]);
> +	}
> +
> +	kfree(displays);
> +
> +	return display;
> +}
> +EXPORT_SYMBOL(drm_client_display_get_first_enabled);
> +
> +unsigned int
> +drm_client_display_preferred_depth(struct drm_client_display *display)
> +{
> +	struct drm_connector *conn;
> +	unsigned int ret;
> +
> +	conn = drm_connector_lookup(display->client->dev, NULL,
> +				    display->connectors[0]->conn_id);
> +	if (!conn)
> +		return 0;
> +
> +	if (conn->cmdline_mode.bpp_specified)
> +		ret = conn->cmdline_mode.bpp;
> +	else
> +		ret = display->client->dev->mode_config.preferred_depth;
> +
> +	drm_connector_put(conn);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL(drm_client_display_preferred_depth);
> +
> +int drm_client_display_dpms(struct drm_client_display *display, int mode)
> +{
> +	struct drm_mode_obj_set_property prop;
> +
> +	prop.value = mode;
> +	prop.prop_id = display->client->dev->mode_config.dpms_property->base.id;
> +	prop.obj_id = display->connectors[0]->conn_id;
> +	prop.obj_type = DRM_MODE_OBJECT_CONNECTOR;
> +
> +	return drm_mode_obj_set_property(display->client->dev, &prop,
> +					 display->client->file);
> +}
> +EXPORT_SYMBOL(drm_client_display_dpms);
> +
> +int drm_client_display_wait_vblank(struct drm_client_display *display)
> +{
> +	struct drm_crtc *crtc;
> +	union drm_wait_vblank vblank_req = {
> +		.request = {
> +			.type = _DRM_VBLANK_RELATIVE,
> +			.sequence = 1,
> +		},
> +	};
> +
> +	crtc = drm_crtc_find(display->client->dev, display->client->file,
> +			     display->connectors[0]->crtc_id);
> +	if (!crtc)
> +		return -ENOENT;
> +
> +	vblank_req.request.type |= drm_crtc_index(crtc) << _DRM_VBLANK_HIGH_CRTC_SHIFT;
> +
> +	return drm_wait_vblank(display->client->dev, &vblank_req,
> +			       display->client->file);
> +}
> +EXPORT_SYMBOL(drm_client_display_wait_vblank);
> +
> +static int drm_client_get_crtc_index(struct drm_client_dev *client, u32 id)
> +{
> +	int i;
> +
> +	for (i = 0; i < client->num_crtcs; i++)
> +		if (client->crtcs[i] == id)
> +			return i;
> +
> +	return -ENOENT;
> +}
> +
> +static int drm_client_display_find_crtcs(struct drm_client_display *display)
> +{
> +	struct drm_client_dev *client = display->client;
> +	struct drm_device *dev = client->dev;
> +	struct drm_file *file = client->file;
> +	u32 encoder_ids[DRM_CONNECTOR_MAX_ENCODER];
> +	unsigned int i, j, available_crtcs = ~0;
> +	struct drm_mode_get_connector conn_req;
> +	struct drm_mode_get_encoder enc_req;
> +	int ret;
> +
> +	/* Already done? */
> +	if (display->connectors[0]->crtc_id)
> +		return 0;
> +
> +	for (i = 0; i < display->num_connectors; i++) {
> +		u32 active_crtcs = 0, crtcs_for_connector = 0;
> +		int crtc_idx;
> +
> +		memset(&conn_req, 0, sizeof(conn_req));
> +		conn_req.connector_id = display->connectors[i]->conn_id;
> +		conn_req.encoders_ptr = (unsigned long)(encoder_ids);
> +		conn_req.count_encoders = DRM_CONNECTOR_MAX_ENCODER;
> +		ret = drm_mode_getconnector(dev, &conn_req, file, false);
> +		if (ret)
> +			return ret;
> +
> +		if (conn_req.encoder_id) {
> +			memset(&enc_req, 0, sizeof(enc_req));
> +			enc_req.encoder_id = conn_req.encoder_id;
> +			ret = drm_mode_getencoder(dev, &enc_req, file);
> +			if (ret)
> +				return ret;
> +			crtcs_for_connector |= enc_req.possible_crtcs;
> +			if (crtcs_for_connector & available_crtcs)
> +				goto found;
> +		}
> +
> +		for (j = 0; j < conn_req.count_encoders; j++) {
> +			memset(&enc_req, 0, sizeof(enc_req));
> +			enc_req.encoder_id = encoder_ids[j];
> +			ret = drm_mode_getencoder(dev, &enc_req, file);
> +			if (ret)
> +				return ret;
> +
> +			crtcs_for_connector |= enc_req.possible_crtcs;
> +
> +			if (enc_req.crtc_id) {
> +				crtc_idx = drm_client_get_crtc_index(client, enc_req.crtc_id);
> +				if (crtc_idx >= 0)
> +					active_crtcs |= 1 << crtc_idx;
> +			}
> +		}
> +
> +found:
> +		crtcs_for_connector &= available_crtcs;
> +		active_crtcs &= available_crtcs;
> +
> +		if (!crtcs_for_connector)
> +			return -ENOENT;
> +
> +		if (active_crtcs)
> +			crtc_idx = ffs(active_crtcs) - 1;
> +		else
> +			crtc_idx = ffs(crtcs_for_connector) - 1;
> +
> +		if (crtc_idx >= client->num_crtcs)
> +			return -EINVAL;
> +
> +		display->connectors[i]->crtc_id = client->crtcs[crtc_idx];
> +		available_crtcs &= ~BIT(crtc_idx);
> +	}
> +
> +	return 0;
> +}
> +
> +/**
> + * drm_client_display_commit_mode - Commit a mode to the crtc(s)
> + * @display: Client display
> + * @fb_id: Framebuffer id
> + * @mode: Video mode
> + *
> + * Returns:
> + * Zero on success, negative error code on failure.
> + */
> +int drm_client_display_commit_mode(struct drm_client_display *display,
> +				   u32 fb_id, struct drm_mode_modeinfo *mode)
> +{
> +	struct drm_client_dev *client = display->client;
> +	struct drm_device *dev = client->dev;
> +	unsigned int num_crtcs = client->num_crtcs;
> +	struct drm_file *file = client->file;
> +	unsigned int *xoffsets = NULL, *yoffsets = NULL;
> +	struct drm_mode_crtc *crtc_reqs, *req;
> +	u32 cloned_conn_ids[2];
> +	unsigned int i;
> +	int idx, ret;
> +
> +	ret = drm_client_display_find_crtcs(display);
> +	if (ret)
> +		return ret;
> +
> +	crtc_reqs = kcalloc(num_crtcs, sizeof(*crtc_reqs), GFP_KERNEL);
> +	if (!crtc_reqs)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < num_crtcs; i++)
> +		crtc_reqs[i].crtc_id = client->crtcs[i];
> +
> +	if (drm_client_display_is_tiled(display)) {
> +		/* TODO calculate tile crtc offsets */
> +	}
> +
> +	for (i = 0; i < display->num_connectors; i++) {
> +		idx = drm_client_get_crtc_index(client, display->connectors[i]->crtc_id);
> +		if (idx < 0)
> +			return -ENOENT;
> +
> +		req = &crtc_reqs[idx];
> +
> +		req->fb_id = fb_id;
> +		if (xoffsets) {
> +			req->x = xoffsets[i];
> +			req->y = yoffsets[i];
> +		}
> +		req->mode_valid = 1;
> +		req->mode = *mode;
> +
> +		if (display->cloned) {
> +			cloned_conn_ids[0] = display->connectors[0]->conn_id;
> +			cloned_conn_ids[1] = display->connectors[1]->conn_id;
> +			req->set_connectors_ptr = (unsigned long)(cloned_conn_ids);
> +			req->count_connectors = 2;
> +			break;
> +		}
> +
> +		req->set_connectors_ptr = (unsigned long)(&display->connectors[i]->conn_id);
> +		req->count_connectors = 1;
> +	}
> +
> +	for (i = 0; i < num_crtcs; i++) {
> +		ret = drm_mode_setcrtc(dev, &crtc_reqs[i], file, false);
> +		if (ret)
> +			break;
> +	}
> +
> +	kfree(xoffsets);
> +	kfree(yoffsets);
> +	kfree(crtc_reqs);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL(drm_client_display_commit_mode);
> +
> +unsigned int drm_client_display_current_fb(struct drm_client_display *display)
> +{
> +	struct drm_client_dev *client = display->client;
> +	int ret;
> +	struct drm_mode_crtc crtc_req = {
> +		.crtc_id = display->connectors[0]->crtc_id,
> +	};
> +
> +	ret = drm_mode_getcrtc(client->dev, &crtc_req, client->file);
> +	if (ret)
> +		return 0;
> +
> +	return crtc_req.fb_id;
> +}
> +EXPORT_SYMBOL(drm_client_display_current_fb);
> +
> +int drm_client_display_flush(struct drm_client_display *display, u32 fb_id,
> +			     struct drm_clip_rect *clips, unsigned int num_clips)
> +{
> +	struct drm_client_dev *client = display->client;
> +	struct drm_mode_fb_dirty_cmd dirty_req = {
> +		.fb_id = fb_id,
> +		.clips_ptr = (unsigned long)clips,
> +		.num_clips = num_clips,
> +	};
> +	int ret;
> +
> +	if (display->no_flushing)
> +		return 0;
> +
> +	ret = drm_mode_dirtyfb(client->dev, &dirty_req, client->file, false);
> +	if (ret == -ENOSYS) {
> +		ret = 0;
> +		display->no_flushing = true;
> +	}
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL(drm_client_display_flush);
> +
> +int drm_client_display_page_flip(struct drm_client_display *display, u32 fb_id,
> +				 bool event)
> +{
> +	struct drm_client_dev *client = display->client;
> +	struct drm_mode_crtc_page_flip_target page_flip_req = {
> +		.crtc_id = display->connectors[0]->crtc_id,
> +		.fb_id = fb_id,
> +	};
> +
> +	if (event)
> +		page_flip_req.flags = DRM_MODE_PAGE_FLIP_EVENT;
> +
> +	return drm_mode_page_flip(client->dev, &page_flip_req, client->file);
> +	/*
> +	 * TODO:
> +	 * Where do we flush on page flip? Should the driver handle that?
> +	 */
> +}
> +EXPORT_SYMBOL(drm_client_display_page_flip);
> +
> +/**
> + * drm_client_framebuffer_create - Create a client framebuffer
> + * @client: DRM client
> + * @mode: Display mode to create a buffer for
> + * @format: Buffer format
> + *
> + * This function creates a &drm_client_buffer which consists of a
> + * &drm_framebuffer backed by a dumb buffer. The dumb buffer is &dma_buf
> + * exported to aquire a virtual address which is stored in
> + * &drm_client_buffer->vaddr.
> + * Call drm_client_framebuffer_delete() to free the buffer.
> + *
> + * Returns:
> + * Pointer to a client buffer or an error pointer on failure.
> + */
> +struct drm_client_buffer *
> +drm_client_framebuffer_create(struct drm_client_dev *client,
> +			      struct drm_mode_modeinfo *mode, u32 format)
> +{
> +	struct drm_client_buffer *buffer;
> +	int ret;
> +
> +	buffer = drm_client_buffer_create(client, mode->hdisplay,
> +					  mode->vdisplay, format);
> +	if (IS_ERR(buffer))
> +		return buffer;
> +
> +	ret = drm_client_buffer_addfb(buffer, mode);
> +	if (ret) {
> +		drm_client_buffer_delete(buffer);
> +		return ERR_PTR(ret);
> +	}
> +
> +	return buffer;
> +}
> +EXPORT_SYMBOL(drm_client_framebuffer_create);
> +
> +void drm_client_framebuffer_delete(struct drm_client_buffer *buffer)
> +{
> +	drm_client_buffer_rmfb(buffer);
> +	drm_client_buffer_delete(buffer);
> +}
> +EXPORT_SYMBOL(drm_client_framebuffer_delete);
> +
> +struct drm_client_buffer *
> +drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height,
> +			 u32 format)
> +{
> +	struct drm_mode_create_dumb dumb_args = { 0 };
> +	struct drm_prime_handle prime_args = { 0 };
> +	struct drm_client_buffer *buffer;
> +	struct dma_buf *dma_buf;
> +	void *vaddr;
> +	int ret;
> +
> +	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
> +	if (!buffer)
> +		return ERR_PTR(-ENOMEM);
> +
> +	ret = drm_client_get_file(client);
> +	if (ret)
> +		goto err_free;
> +
> +	buffer->client = client;
> +	buffer->width = width;
> +	buffer->height = height;
> +	buffer->format = format;
> +
> +	dumb_args.width = buffer->width;
> +	dumb_args.height = buffer->height;
> +	dumb_args.bpp = drm_format_plane_cpp(format, 0) * 8;
> +	ret = drm_mode_create_dumb(client->dev, &dumb_args, client->file);
> +	if (ret)
> +		goto err_put_file;
> +
> +	buffer->handle = dumb_args.handle;
> +	buffer->pitch = dumb_args.pitch;
> +	buffer->size = dumb_args.size;
> +
> +	prime_args.handle = dumb_args.handle;
> +	ret = drm_prime_handle_to_fd(client->dev, &prime_args, client->file);
> +	if (ret)
> +		goto err_delete;
> +
> +	dma_buf = dma_buf_get(prime_args.fd);
> +	if (IS_ERR(dma_buf)) {
> +		ret = PTR_ERR(dma_buf);
> +		goto err_delete;
> +	}
> +
> +	buffer->dma_buf = dma_buf;
> +
> +	vaddr = dma_buf_vmap(dma_buf);
> +	if (!vaddr) {
> +		ret = -ENOMEM;
> +		goto err_delete;
> +	}
> +
> +	buffer->vaddr = vaddr;
> +
> +	return buffer;
> +
> +err_delete:
> +	drm_client_buffer_delete(buffer);
> +err_put_file:
> +	drm_client_put_file(client);
> +err_free:
> +	kfree(buffer);
> +
> +	return ERR_PTR(ret);
> +}
> +EXPORT_SYMBOL(drm_client_buffer_create);
> +
> +void drm_client_buffer_delete(struct drm_client_buffer *buffer)
> +{
> +	if (!buffer)
> +		return;
> +
> +	if (buffer->vaddr)
> +		dma_buf_vunmap(buffer->dma_buf, buffer->vaddr);
> +
> +	if (buffer->dma_buf)
> +		dma_buf_put(buffer->dma_buf);
> +
> +	drm_mode_destroy_dumb(buffer->client->dev, buffer->handle,
> +			      buffer->client->file);
> +	drm_client_put_file(buffer->client);
> +	kfree(buffer);
> +}
> +EXPORT_SYMBOL(drm_client_buffer_delete);
> +
> +int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
> +			    struct drm_mode_modeinfo *mode)
> +{
> +	struct drm_client_dev *client = buffer->client;
> +	struct drm_mode_fb_cmd2 fb_req = { };
> +	unsigned int num_fbs, *fb_ids;
> +	int i, ret;
> +
> +	if (buffer->num_fbs)
> +		return -EINVAL;
> +
> +	if (mode->hdisplay > buffer->width || mode->vdisplay > buffer->height)
> +		return -EINVAL;
> +
> +	num_fbs = buffer->height / mode->vdisplay;
> +	fb_ids = kcalloc(num_fbs, sizeof(*fb_ids), GFP_KERNEL);
> +	if (!fb_ids)
> +		return -ENOMEM;
> +
> +	fb_req.width = mode->hdisplay;
> +	fb_req.height = mode->vdisplay;
> +	fb_req.pixel_format = buffer->format;
> +	fb_req.handles[0] = buffer->handle;
> +	fb_req.pitches[0] = buffer->pitch;
> +
> +	for (i = 0; i < num_fbs; i++) {
> +		fb_req.offsets[0] = i * mode->vdisplay * buffer->pitch;
> +		ret = drm_mode_addfb2(client->dev, &fb_req, client->file,
> +				      client->funcs->name);
> +		if (ret)
> +			goto err_remove;
> +		fb_ids[i] = fb_req.fb_id;
> +	}
> +
> +	buffer->fb_ids = fb_ids;
> +	buffer->num_fbs = num_fbs;
> +
> +	return 0;
> +
> +err_remove:
> +	for (i--; i >= 0; i--)
> +		drm_mode_rmfb(client->dev, fb_ids[i], client->file);
> +	kfree(fb_ids);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL(drm_client_buffer_addfb);
> +
> +int drm_client_buffer_rmfb(struct drm_client_buffer *buffer)
> +{
> +	unsigned int i;
> +	int ret;
> +
> +	if (!buffer || !buffer->num_fbs)
> +		return 0;
> +
> +	for (i = 0; i < buffer->num_fbs; i++) {
> +		ret = drm_mode_rmfb(buffer->client->dev, buffer->fb_ids[i],
> +				    buffer->client->file);
> +		if (ret)
> +			DRM_DEV_ERROR(buffer->client->dev->dev,
> +				      "Error removing FB:%u (%d)\n",
> +				      buffer->fb_ids[i], ret);
> +	}
> +
> +	kfree(buffer->fb_ids);
> +	buffer->fb_ids = NULL;
> +	buffer->num_fbs = 0;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(drm_client_buffer_rmfb);
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index f869de185986..db161337d87c 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -33,6 +33,7 @@
>  #include <linux/mount.h>
>  #include <linux/slab.h>
>  
> +#include <drm/drm_client.h>
>  #include <drm/drm_drv.h>
>  #include <drm/drmP.h>
>  
> @@ -463,6 +464,7 @@ int drm_dev_init(struct drm_device *dev,
>  	dev->driver = driver;
>  
>  	INIT_LIST_HEAD(&dev->filelist);
> +	INIT_LIST_HEAD(&dev->filelist_internal);
>  	INIT_LIST_HEAD(&dev->ctxlist);
>  	INIT_LIST_HEAD(&dev->vmalist);
>  	INIT_LIST_HEAD(&dev->maplist);
> @@ -787,6 +789,8 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags)
>  		 dev->dev ? dev_name(dev->dev) : "virtual device",
>  		 dev->primary->index);
>  
> +	drm_client_dev_register(dev);
> +
>  	goto out_unlock;
>  
>  err_minors:
> @@ -839,6 +843,8 @@ void drm_dev_unregister(struct drm_device *dev)
>  	drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
>  	drm_minor_unregister(dev, DRM_MINOR_RENDER);
>  	drm_minor_unregister(dev, DRM_MINOR_CONTROL);
> +
> +	drm_client_dev_unregister(dev);
>  }
>  EXPORT_SYMBOL(drm_dev_unregister);
>  
> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
> index 55505378df47..bcc688e58776 100644
> --- a/drivers/gpu/drm/drm_file.c
> +++ b/drivers/gpu/drm/drm_file.c
> @@ -35,6 +35,7 @@
>  #include <linux/slab.h>
>  #include <linux/module.h>
>  
> +#include <drm/drm_client.h>
>  #include <drm/drm_file.h>
>  #include <drm/drmP.h>
>  
> @@ -443,6 +444,8 @@ void drm_lastclose(struct drm_device * dev)
>  
>  	if (drm_core_check_feature(dev, DRIVER_LEGACY))
>  		drm_legacy_dev_reinit(dev);
> +
> +	drm_client_dev_lastclose(dev);
>  }
>  
>  /**
> diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
> index 2d1643bdae78..5d2a6c6717f5 100644
> --- a/drivers/gpu/drm/drm_probe_helper.c
> +++ b/drivers/gpu/drm/drm_probe_helper.c
> @@ -33,6 +33,7 @@
>  #include <linux/moduleparam.h>
>  
>  #include <drm/drmP.h>
> +#include <drm/drm_client.h>
>  #include <drm/drm_crtc.h>
>  #include <drm/drm_fourcc.h>
>  #include <drm/drm_crtc_helper.h>
> @@ -563,6 +564,8 @@ void drm_kms_helper_hotplug_event(struct drm_device *dev)
>  	drm_sysfs_hotplug_event(dev);
>  	if (dev->mode_config.funcs->output_poll_changed)
>  		dev->mode_config.funcs->output_poll_changed(dev);
> +
> +	drm_client_dev_hotplug(dev);
>  }
>  EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
>  
> diff --git a/include/drm/drm_client.h b/include/drm/drm_client.h
> new file mode 100644
> index 000000000000..88f6f87919c5
> --- /dev/null
> +++ b/include/drm/drm_client.h
> @@ -0,0 +1,192 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#include <linux/mutex.h>
> +
> +struct dma_buf;
> +struct drm_clip_rect;
> +struct drm_device;
> +struct drm_file;
> +struct drm_mode_modeinfo;
> +
> +struct drm_client_dev;
> +
> +/**
> + * struct drm_client_funcs - DRM client  callbacks
> + */
> +struct drm_client_funcs {
> +	/**
> +	 * @name:
> +	 *
> +	 * Name of the client.
> +	 */
> +	const char *name;
> +
> +	/**
> +	 * @new:
> +	 *
> +	 * Called when a client or a &drm_device is registered.
> +	 * If the callback returns anything but zero, then this client instance
> +	 * is dropped.
> +	 *
> +	 * This callback is mandatory.
> +	 */
> +	int (*new)(struct drm_client_dev *client);
> +
> +	/**
> +	 * @remove:
> +	 *
> +	 * Called when a &drm_device is unregistered or the client is
> +	 * unregistered. If zero is returned drm_client_free() is called
> +	 * automatically. If the client can't drop it's resources it should
> +	 * return non-zero and call drm_client_free() later.
> +	 *
> +	 * This callback is optional.
> +	 */
> +	int (*remove)(struct drm_client_dev *client);
> +
> +	/**
> +	 * @lastclose:
> +	 *
> +	 * Called on drm_lastclose(). The first client instance in the list
> +	 * that returns zero gets the privilege to restore and no more clients
> +	 * are called.
> +	 *
> +	 * This callback is optional.
> +	 */
> +	int (*lastclose)(struct drm_client_dev *client);
> +
> +	/**
> +	 * @hotplug:
> +	 *
> +	 * Called on drm_kms_helper_hotplug_event().
> +	 *
> +	 * This callback is optional.
> +	 */
> +	int (*hotplug)(struct drm_client_dev *client);
> +
> +// TODO
> +//	void (*suspend)(struct drm_client_dev *client);
> +//	void (*resume)(struct drm_client_dev *client);
> +};
> +
> +/**
> + * struct drm_client_dev - DRM client instance
> + */
> +struct drm_client_dev {
> +	struct list_head list;
> +	struct drm_device *dev;
> +	const struct drm_client_funcs *funcs;
> +	struct mutex lock;
> +	struct drm_file *file;
> +	unsigned int file_ref_count;
> +	u32 *crtcs;
> +	unsigned int num_crtcs;
> +	u32 min_width;
> +	u32 max_width;
> +	u32 min_height;
> +	u32 max_height;
> +	void *private;
> +};
> +
> +void drm_client_free(struct drm_client_dev *client);
> +int drm_client_register(const struct drm_client_funcs *funcs);
> +void drm_client_unregister(const struct drm_client_funcs *funcs);
> +
> +void drm_client_dev_register(struct drm_device *dev);
> +void drm_client_dev_unregister(struct drm_device *dev);
> +void drm_client_dev_hotplug(struct drm_device *dev);
> +void drm_client_dev_lastclose(struct drm_device *dev);
> +
> +int drm_client_get_file(struct drm_client_dev *client);
> +void drm_client_put_file(struct drm_client_dev *client);
> +struct drm_event *
> +drm_client_read_event(struct drm_client_dev *client, bool block);
> +
> +struct drm_client_connector {
> +	unsigned int conn_id;
> +	unsigned int status;
> +	unsigned int crtc_id;
> +	struct drm_mode_modeinfo *modes;
> +	unsigned int num_modes;
> +	bool has_tile;
> +	int tile_group;
> +	u8 tile_h_loc, tile_v_loc;
> +};
> +
> +struct drm_client_display {
> +	struct drm_client_dev *client;
> +
> +	struct drm_client_connector **connectors;
> +	unsigned int num_connectors;
> +
> +	struct mutex modes_lock;
> +	struct drm_mode_modeinfo *modes;
> +	unsigned int num_modes;
> +
> +	bool cloned;
> +	bool no_flushing;
> +};
> +
> +void drm_client_display_free(struct drm_client_display *display);
> +struct drm_client_display *
> +drm_client_display_get_first_enabled(struct drm_client_dev *client, bool strict);
> +
> +int drm_client_display_update_modes(struct drm_client_display *display,
> +				    bool *mode_changed);
> +
> +static inline bool
> +drm_client_display_is_tiled(struct drm_client_display *display)
> +{
> +	return !display->cloned && display->num_connectors > 1;
> +}
> +
> +int drm_client_display_dpms(struct drm_client_display *display, int mode);
> +int drm_client_display_wait_vblank(struct drm_client_display *display);
> +
> +struct drm_mode_modeinfo *
> +drm_client_display_first_mode(struct drm_client_display *display);
> +struct drm_mode_modeinfo *
> +drm_client_display_next_mode(struct drm_client_display *display,
> +			     struct drm_mode_modeinfo *mode);
> +
> +#define drm_client_display_for_each_mode(display, mode) \
> +	for (mode = drm_client_display_first_mode(display); mode; \
> +	     mode = drm_client_display_next_mode(display, mode))
> +
> +unsigned int
> +drm_client_display_preferred_depth(struct drm_client_display *display);
> +
> +int drm_client_display_commit_mode(struct drm_client_display *display,
> +				   u32 fb_id, struct drm_mode_modeinfo *mode);
> +unsigned int drm_client_display_current_fb(struct drm_client_display *display);
> +int drm_client_display_flush(struct drm_client_display *display, u32 fb_id,
> +			     struct drm_clip_rect *clips, unsigned int num_clips);
> +int drm_client_display_page_flip(struct drm_client_display *display, u32 fb_id,
> +				 bool event);
> +
> +struct drm_client_buffer {
> +	struct drm_client_dev *client;
> +	u32 width;
> +	u32 height;
> +	u32 format;
> +	u32 handle;
> +	u32 pitch;
> +	u64 size;
> +	struct dma_buf *dma_buf;
> +	void *vaddr;
> +
> +	unsigned int *fb_ids;
> +	unsigned int num_fbs;
> +};
> +
> +struct drm_client_buffer *
> +drm_client_framebuffer_create(struct drm_client_dev *client,
> +			      struct drm_mode_modeinfo *mode, u32 format);
> +void drm_client_framebuffer_delete(struct drm_client_buffer *buffer);
> +struct drm_client_buffer *
> +drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height,
> +			 u32 format);
> +void drm_client_buffer_delete(struct drm_client_buffer *buffer);
> +int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
> +			    struct drm_mode_modeinfo *mode);
> +int drm_client_buffer_rmfb(struct drm_client_buffer *buffer);
> diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h
> index 7c4fa32f3fc6..32dfed3d5a86 100644
> --- a/include/drm/drm_device.h
> +++ b/include/drm/drm_device.h
> @@ -67,6 +67,7 @@ struct drm_device {
>  
>  	struct mutex filelist_mutex;
>  	struct list_head filelist;
> +	struct list_head filelist_internal;
>  
>  	/** \name Memory management */
>  	/*@{ */
> diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
> index 5176c3797680..39af8a4be7b3 100644
> --- a/include/drm/drm_file.h
> +++ b/include/drm/drm_file.h
> @@ -248,6 +248,13 @@ struct drm_file {
>  	 */
>  	void *driver_priv;
>  
> +	/**
> +	 * @user_priv:
> +	 *
> +	 * Optional pointer for user private data. Useful for in-kernel clients.
> +	 */
> +	void *user_priv;
> +
>  	/**
>  	 * @fbs:
>  	 *
> -- 
> 2.15.1
>

Noralf Trønnes March 8, 2018, 5:12 p.m. UTC | #2

Den 06.03.2018 09.56, skrev Daniel Vetter:
> On Thu, Feb 22, 2018 at 09:06:50PM +0100, Noralf Trønnes wrote:
>> This adds an API for writing in-kernel clients.
>>
>> TODO:
>> - Flesh out and complete documentation.
>> - Cloned displays is not tested.
>> - Complete tiled display support and test it.
>> - Test plug/unplug different monitors.
>> - A runtime knob to prevent clients from attaching for debugging purposes.
>> - Maybe a way to unbind individual client instances.
>> - Maybe take the sysrq support in drm_fb_helper and move it here somehow.
>> - Add suspend/resume callbacks.
>>    Does anyone know why fbdev requires suspend/resume?
>>
>> Signed-off-by: Noralf Trønnes <[e-mail]>
> The core client api I like. Some of the opens I'm seeing:
>
> - If we go with using the internal kms api directly instead of IOCTL
>    wrappers then a huge pile of the functions you have here aren't needed
>    (e.g. all the event stuff we can just directly use vblank events instead
>    of all the wrapping). I'm leaning ever more into that direction, since
>    much less code to add.

Looking at drm_fb_helper once again I now see an opportunity to simplify
the modesetting code by nuking drm_fb_helper_connector and stop
maintaining an array of connectors. It looks to be possible to just
create an array temporarily in drm_setup_crtcs() for the duration of the
function. The connectors we care about are ref counted and attached to
modesets. This would remove the need for drm_fb_helper_add_one_connector().

So I might be able to do struct drm_fb_helper_crtc -> drm_client_crtc
and let the client API take over drm_setup_crtcs(). I'll give it a try.

There is one challenge I see upfront and that's the i915 fb_helper
callback in drm_setup_crtcs().

> - The register/unregister model needs more thought. Allowing both clients
>    to register whenever they want to, and drm_device instances to come and
>    go is what fbcon has done, and the resulting locking is a horror show.
>
>    I think if we require that all in-kernel drm_clients are registers when
>    loading drm.ko (and enabled/disabled only per module options and
>    Kconfig), then we can throw out all the locking. That avoids a lot of
>    the headaches.
>
>    2nd, if the list of clients is static over the lifetime of drm.ko, we
>    also don't need to iterate existing drivers. Which avoids me having to
>    review the iterator patch (that's the other aspect where fbcon totally
>    falls over and essentially just ignores a bunch of races).

Are you talking about linking the clients into drm.ko?

drivers/gpu/drm/Makefile:

drm-$(CONFIG_DRM_CLIENT_BOOTSPLASH) += client/drm_bootsplash.o

drivers/gpu/drm/drm_drv.c:

  static int __init drm_core_init(void)
  {
+    drm_bootsplash_register();
+    drm_fbdev_register();
  }

drivers/gpu/drm/drm_internal.h:

#ifdef DRM_CLIENT_BOOTSPLASH
void drm_bootsplash_register(void);
#else
static inline void drm_bootsplash_register(void)
{
}
#endif

drivers/gpu/drm/client/drm_bootsplash.c:

static const struct drm_client_funcs drm_bootsplash_funcs = {
     .name        = "drm_bootsplash",
     .new        = drm_bootsplash_new,
     .remove        = drm_bootsplash_remove,
     .hotplug    = drm_bootsplash_hotplug,
};

void drm_bootsplash_register(void)
{
     drm_client_register(&drm_bootsplash_funcs);
}

drivers/gpu/drm/drm_client.c:

static LIST_HEAD(drm_client_funcs_list);

void drm_client_register(const struct drm_client_funcs *funcs)
{
     struct drm_client_funcs_entry *funcs_entry;

     funcs_entry = kzalloc(sizeof(*funcs_entry), GFP_KERNEL);
     if (!funcs_entry) {
         DRM_ERROR("Failed to register: %s\n", funcs->name);
         return;
     }

     funcs_entry->funcs = funcs;

     list_add(&funcs_entry->list, &drm_client_funcs_list);

     DRM_DEBUG_KMS("%s\n", funcs->name);
}


And each client having a runtime enable/disable knob:

drivers/gpu/drm/client/drm_bootsplash.c:

static bool drm_bootsplash_enabled = true;
module_param_named(bootsplash_enabled, drm_bootsplash_enabled, bool, 0600);
MODULE_PARM_DESC(bootsplash_enabled, "Enable bootsplash client 
[default=true]");


Simple USB Display
A few months back while looking at the udl shmem code, I got the idea
that I could turn a Raspberry Pi Zero into a $5 USB to HDMI/DSI/DPI/DBI/TV
adapter. The host side would be a simple tinydrm driver using the kernel
compression lib to speed up transfers. The gadget/device side would be a
userspace app decompressing the buffer into an exported dumb buffer.

While working with this client API I realized that I could use it and
write a kernel gadget driver instead avoiding the challenge of going
back and forth to userspace with the framebuffer. For such a client I
would have preferred it to be a loadable module not linked into drm.ko
to increase the chance that distributions would enable it.

Noralf.

>> ---
>>   drivers/gpu/drm/Kconfig             |    2 +
>>   drivers/gpu/drm/Makefile            |    3 +-
>>   drivers/gpu/drm/client/Kconfig      |    4 +
>>   drivers/gpu/drm/client/Makefile     |    1 +
>>   drivers/gpu/drm/client/drm_client.c | 1612 +++++++++++++++++++++++++++++++++++
> I'd move this into main drm/ directory, it's fairly core stuff.
>
>>   drivers/gpu/drm/drm_drv.c           |    6 +
>>   drivers/gpu/drm/drm_file.c          |    3 +
>>   drivers/gpu/drm/drm_probe_helper.c  |    3 +
>>   include/drm/drm_client.h            |  192 +++++
>>   include/drm/drm_device.h            |    1 +
>>   include/drm/drm_file.h              |    7 +
>>   11 files changed, 1833 insertions(+), 1 deletion(-)
>>   create mode 100644 drivers/gpu/drm/client/Kconfig
>>   create mode 100644 drivers/gpu/drm/client/Makefile
>>   create mode 100644 drivers/gpu/drm/client/drm_client.c
>>   create mode 100644 include/drm/drm_client.h
>>
>> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
>> index deeefa7a1773..d4ae15f9ee9f 100644
>> --- a/drivers/gpu/drm/Kconfig
>> +++ b/drivers/gpu/drm/Kconfig
>> @@ -154,6 +154,8 @@ config DRM_SCHED
>>   	tristate
>>   	depends on DRM
>>   
>> +source "drivers/gpu/drm/client/Kconfig"
>> +
>>   source "drivers/gpu/drm/i2c/Kconfig"
>>   
>>   source "drivers/gpu/drm/arm/Kconfig"
>> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
>> index 50093ff4479b..8e06dc7eeca1 100644
>> --- a/drivers/gpu/drm/Makefile
>> +++ b/drivers/gpu/drm/Makefile
>> @@ -18,7 +18,7 @@ drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
>>   		drm_encoder.o drm_mode_object.o drm_property.o \
>>   		drm_plane.o drm_color_mgmt.o drm_print.o \
>>   		drm_dumb_buffers.o drm_mode_config.o drm_vblank.o \
>> -		drm_syncobj.o drm_lease.o
>> +		drm_syncobj.o drm_lease.o client/drm_client.o
>>   
>>   drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o
>>   drm-$(CONFIG_DRM_VM) += drm_vm.o
>> @@ -103,3 +103,4 @@ obj-$(CONFIG_DRM_MXSFB)	+= mxsfb/
>>   obj-$(CONFIG_DRM_TINYDRM) += tinydrm/
>>   obj-$(CONFIG_DRM_PL111) += pl111/
>>   obj-$(CONFIG_DRM_TVE200) += tve200/
>> +obj-y			+= client/
>> diff --git a/drivers/gpu/drm/client/Kconfig b/drivers/gpu/drm/client/Kconfig
>> new file mode 100644
>> index 000000000000..4bb8e4655ff7
>> --- /dev/null
>> +++ b/drivers/gpu/drm/client/Kconfig
>> @@ -0,0 +1,4 @@
>> +menu "DRM Clients"
>> +	depends on DRM
>> +
>> +endmenu
>> diff --git a/drivers/gpu/drm/client/Makefile b/drivers/gpu/drm/client/Makefile
>> new file mode 100644
>> index 000000000000..f66554cd5c45
>> --- /dev/null
>> +++ b/drivers/gpu/drm/client/Makefile
>> @@ -0,0 +1 @@
>> +# SPDX-License-Identifier: GPL-2.0
>> diff --git a/drivers/gpu/drm/client/drm_client.c b/drivers/gpu/drm/client/drm_client.c
>> new file mode 100644
>> index 000000000000..a633bf747316
>> --- /dev/null
>> +++ b/drivers/gpu/drm/client/drm_client.c
>> @@ -0,0 +1,1612 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +// Copyright 2018 Noralf Trønnes
>> +
>> +#include <linux/dma-buf.h>
>> +#include <linux/list.h>
>> +#include <linux/mutex.h>
>> +#include <linux/module.h>
>> +#include <linux/slab.h>
>> +
>> +#include <drm/drm_client.h>
>> +#include <drm/drm_connector.h>
>> +#include <drm/drm_drv.h>
>> +#include <drm/drm_file.h>
>> +#include <drm/drm_ioctl.h>
>> +#include <drm/drmP.h>
>> +
>> +#include "drm_crtc_internal.h"
>> +#include "drm_internal.h"
>> +
>> +struct drm_client_funcs_entry {
>> +	struct list_head list;
>> +	const struct drm_client_funcs *funcs;
>> +};
>> +
>> +static LIST_HEAD(drm_client_list);
> I think the client list itself should be on the drm_device, not in one
> global list that mixes up all the clients of all the drm_devices.
>
> I'll skip reviewing details since we have a bunch of high-level questions
> to figure out first.
> -Daniel
>
>> +static LIST_HEAD(drm_client_funcs_list);
>> +static DEFINE_MUTEX(drm_client_list_lock);
>> +
>> +static void drm_client_new(struct drm_device *dev,
>> +			   const struct drm_client_funcs *funcs)
>> +{
>> +	struct drm_client_dev *client;
>> +	int ret;
>> +
>> +	lockdep_assert_held(&drm_client_list_lock);
>> +
>> +	client = kzalloc(sizeof(*client), GFP_KERNEL);
>> +	if (!client)
>> +		return;
>> +
>> +	mutex_init(&client->lock);
>> +	client->dev = dev;
>> +	client->funcs = funcs;
>> +
>> +	ret = funcs->new(client);
>> +	DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n", funcs->name, ret);
>> +	if (ret) {
>> +		drm_client_free(client);
>> +		return;
>> +	}
>> +
>> +	list_add(&client->list, &drm_client_list);
>> +}
>> +
>> +/**
>> + * drm_client_free - Free DRM client resources
>> + * @client: DRM client
>> + *
>> + * This is called automatically on client removal unless the client returns
>> + * non-zero in the &drm_client_funcs->remove callback. The fbdev client does
>> + * this when it can't close &drm_file because userspace has an open fd.
>> + */
>> +void drm_client_free(struct drm_client_dev *client)
>> +{
>> +	DRM_DEV_DEBUG_KMS(client->dev->dev, "%s\n", client->funcs->name);
>> +	if (WARN_ON(client->file)) {
>> +		client->file_ref_count = 1;
>> +		drm_client_put_file(client);
>> +	}
>> +	mutex_destroy(&client->lock);
>> +	kfree(client->crtcs);
>> +	kfree(client);
>> +}
>> +EXPORT_SYMBOL(drm_client_free);
>> +
>> +static void drm_client_remove(struct drm_client_dev *client)
>> +{
>> +	lockdep_assert_held(&drm_client_list_lock);
>> +
>> +	list_del(&client->list);
>> +
>> +	if (!client->funcs->remove || !client->funcs->remove(client))
>> +		drm_client_free(client);
>> +}
>> +
>> +/**
>> + * drm_client_register - Register a DRM client
>> + * @funcs: Client callbacks
>> + *
>> + * Returns:
>> + * Zero on success, negative error code on failure.
>> + */
>> +int drm_client_register(const struct drm_client_funcs *funcs)
>> +{
>> +	struct drm_client_funcs_entry *funcs_entry;
>> +	struct drm_device_list_iter iter;
>> +	struct drm_device *dev;
>> +
>> +	funcs_entry = kzalloc(sizeof(*funcs_entry), GFP_KERNEL);
>> +	if (!funcs_entry)
>> +		return -ENOMEM;
>> +
>> +	funcs_entry->funcs = funcs;
>> +
>> +	mutex_lock(&drm_global_mutex);
>> +	mutex_lock(&drm_client_list_lock);
>> +
>> +	drm_device_list_iter_begin(&iter);
>> +	drm_for_each_device_iter(dev, &iter)
>> +		if (drm_core_check_feature(dev, DRIVER_MODESET))
>> +			drm_client_new(dev, funcs);
>> +	drm_device_list_iter_end(&iter);
>> +
>> +	list_add(&funcs_entry->list, &drm_client_funcs_list);
>> +
>> +	mutex_unlock(&drm_client_list_lock);
>> +	mutex_unlock(&drm_global_mutex);
>> +
>> +	DRM_DEBUG_KMS("%s\n", funcs->name);
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL(drm_client_register);
>> +
>> +/**
>> + * drm_client_unregister - Unregister a DRM client
>> + * @funcs: Client callbacks
>> + */
>> +void drm_client_unregister(const struct drm_client_funcs *funcs)
>> +{
>> +	struct drm_client_funcs_entry *funcs_entry;
>> +	struct drm_client_dev *client, *tmp;
>> +
>> +	mutex_lock(&drm_client_list_lock);
>> +
>> +	list_for_each_entry_safe(client, tmp, &drm_client_list, list) {
>> +		if (client->funcs == funcs)
>> +			drm_client_remove(client);
>> +	}
>> +
>> +	list_for_each_entry(funcs_entry, &drm_client_funcs_list, list) {
>> +		if (funcs_entry->funcs == funcs) {
>> +			list_del(&funcs_entry->list);
>> +			kfree(funcs_entry);
>> +			break;
>> +		}
>> +	}
>> +
>> +	mutex_unlock(&drm_client_list_lock);
>> +
>> +	DRM_DEBUG_KMS("%s\n", funcs->name);
>> +}
>> +EXPORT_SYMBOL(drm_client_unregister);
>> +
>> +void drm_client_dev_register(struct drm_device *dev)
>> +{
>> +	struct drm_client_funcs_entry *funcs_entry;
>> +
>> +	/*
>> +	 * Minors are created at the beginning of drm_dev_register(), but can
>> +	 * be removed again if the function fails. Since we iterate DRM devices
>> +	 * by walking DRM minors, we need to stay under this lock.
>> +	 */
>> +	lockdep_assert_held(&drm_global_mutex);
>> +
>> +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
>> +		return;
>> +
>> +	mutex_lock(&drm_client_list_lock);
>> +	list_for_each_entry(funcs_entry, &drm_client_funcs_list, list)
>> +		drm_client_new(dev, funcs_entry->funcs);
>> +	mutex_unlock(&drm_client_list_lock);
>> +}
>> +
>> +void drm_client_dev_unregister(struct drm_device *dev)
>> +{
>> +	struct drm_client_dev *client, *tmp;
>> +
>> +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
>> +		return;
>> +
>> +	mutex_lock(&drm_client_list_lock);
>> +	list_for_each_entry_safe(client, tmp, &drm_client_list, list)
>> +		if (client->dev == dev)
>> +			drm_client_remove(client);
>> +	mutex_unlock(&drm_client_list_lock);
>> +}
>> +
>> +void drm_client_dev_hotplug(struct drm_device *dev)
>> +{
>> +	struct drm_client_dev *client;
>> +	int ret;
>> +
>> +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
>> +		return;
>> +
>> +	mutex_lock(&drm_client_list_lock);
>> +	list_for_each_entry(client, &drm_client_list, list)
>> +		if (client->dev == dev && client->funcs->hotplug) {
>> +			ret = client->funcs->hotplug(client);
>> +			DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n",
>> +					  client->funcs->name, ret);
>> +		}
>> +	mutex_unlock(&drm_client_list_lock);
>> +}
>> +
>> +void drm_client_dev_lastclose(struct drm_device *dev)
>> +{
>> +	struct drm_client_dev *client;
>> +	int ret;
>> +
>> +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
>> +		return;
>> +
>> +	mutex_lock(&drm_client_list_lock);
>> +	list_for_each_entry(client, &drm_client_list, list)
>> +		if (client->dev == dev && client->funcs->lastclose) {
>> +			ret = client->funcs->lastclose(client);
>> +			DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n",
>> +					  client->funcs->name, ret);
>> +		}
>> +	mutex_unlock(&drm_client_list_lock);
>> +}
>> +
>> +/* Get static info */
>> +static int drm_client_init(struct drm_client_dev *client, struct drm_file *file)
>> +{
>> +	struct drm_mode_card_res card_res = {};
>> +	struct drm_device *dev = client->dev;
>> +	u32 *crtcs;
>> +	int ret;
>> +
>> +	ret = drm_mode_getresources(dev, &card_res, file, false);
>> +	if (ret)
>> +		return ret;
>> +	if (!card_res.count_crtcs)
>> +		return -ENOENT;
>> +
>> +	crtcs = kmalloc_array(card_res.count_crtcs, sizeof(*crtcs), GFP_KERNEL);
>> +	if (!crtcs)
>> +		return -ENOMEM;
>> +
>> +	card_res.count_fbs = 0;
>> +	card_res.count_connectors = 0;
>> +	card_res.count_encoders = 0;
>> +	card_res.crtc_id_ptr = (unsigned long)crtcs;
>> +
>> +	ret = drm_mode_getresources(dev, &card_res, file, false);
>> +	if (ret) {
>> +		kfree(crtcs);
>> +		return ret;
>> +	}
>> +
>> +	client->crtcs = crtcs;
>> +	client->num_crtcs = card_res.count_crtcs;
>> +	client->min_width = card_res.min_width;
>> +	client->max_width = card_res.max_width;
>> +	client->min_height = card_res.min_height;
>> +	client->max_height = card_res.max_height;
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * drm_client_get_file - Get a DRM file
>> + * @client: DRM client
>> + *
>> + * This function makes sure the client has a &drm_file available. The client
>> + * doesn't normally need to call this, since all client functions that depends
>> + * on a DRM file will call it. A matching call to drm_client_put_file() is
>> + * necessary.
>> + *
>> + * The reason for not opening a DRM file when a @client is created is because
>> + * we have to take a ref on the driver module due to &drm_driver->postclose
>> + * being called in drm_file_free(). Having a DRM file open for the lifetime of
>> + * the client instance would block driver module unload.
>> + *
>> + * Returns:
>> + * Zero on success, negative error code on failure.
>> + */
>> +int drm_client_get_file(struct drm_client_dev *client)
>> +{
>> +	struct drm_device *dev = client->dev;
>> +	struct drm_file *file;
>> +	int ret = 0;
>> +
>> +	mutex_lock(&client->lock);
>> +
>> +	if (client->file_ref_count++) {
>> +		mutex_unlock(&client->lock);
>> +		return 0;
>> +	}
>> +
>> +	if (!try_module_get(dev->driver->fops->owner)) {
>> +		ret = -ENODEV;
>> +		goto err_unlock;
>> +	}
>> +
>> +	drm_dev_get(dev);
>> +
>> +	file = drm_file_alloc(dev->primary);
>> +	if (IS_ERR(file)) {
>> +		ret = PTR_ERR(file);
>> +		goto err_put;
>> +	}
>> +
>> +	if (!client->crtcs) {
>> +		ret = drm_client_init(client, file);
>> +		if (ret)
>> +			goto err_free;
>> +	}
>> +
>> +	mutex_lock(&dev->filelist_mutex);
>> +	list_add(&file->lhead, &dev->filelist_internal);
>> +	mutex_unlock(&dev->filelist_mutex);
>> +
>> +	client->file = file;
>> +
>> +	mutex_unlock(&client->lock);
>> +
>> +	return 0;
>> +
>> +err_free:
>> +	drm_file_free(file);
>> +err_put:
>> +	drm_dev_put(dev);
>> +	module_put(dev->driver->fops->owner);
>> +err_unlock:
>> +	client->file_ref_count = 0;
>> +	mutex_unlock(&client->lock);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL(drm_client_get_file);
>> +
>> +void drm_client_put_file(struct drm_client_dev *client)
>> +{
>> +	struct drm_device *dev = client->dev;
>> +
>> +	if (!client)
>> +		return;
>> +
>> +	mutex_lock(&client->lock);
>> +
>> +	if (WARN_ON(!client->file_ref_count))
>> +		goto out_unlock;
>> +
>> +	if (--client->file_ref_count)
>> +		goto out_unlock;
>> +
>> +	mutex_lock(&dev->filelist_mutex);
>> +	list_del(&client->file->lhead);
>> +	mutex_unlock(&dev->filelist_mutex);
>> +
>> +	drm_file_free(client->file);
>> +	client->file = NULL;
>> +	drm_dev_put(dev);
>> +	module_put(dev->driver->fops->owner);
>> +out_unlock:
>> +	mutex_unlock(&client->lock);
>> +}
>> +EXPORT_SYMBOL(drm_client_put_file);
>> +
>> +static struct drm_pending_event *
>> +drm_client_read_get_pending_event(struct drm_device *dev, struct drm_file *file)
>> +{
>> +	struct drm_pending_event *e = NULL;
>> +	int ret;
>> +
>> +	ret = mutex_lock_interruptible(&file->event_read_lock);
>> +	if (ret)
>> +		return ERR_PTR(ret);
>> +
>> +	spin_lock_irq(&dev->event_lock);
>> +	if (!list_empty(&file->event_list)) {
>> +		e = list_first_entry(&file->event_list,
>> +				     struct drm_pending_event, link);
>> +		file->event_space += e->event->length;
>> +		list_del(&e->link);
>> +	}
>> +	spin_unlock_irq(&dev->event_lock);
>> +
>> +	mutex_unlock(&file->event_read_lock);
>> +
>> +	return e;
>> +}
>> +
>> +struct drm_event *
>> +drm_client_read_event(struct drm_client_dev *client, bool block)
>> +{
>> +	struct drm_file *file = client->file;
>> +	struct drm_device *dev = client->dev;
>> +	struct drm_pending_event *e;
>> +	struct drm_event *event;
>> +	int ret;
>> +
>> +	/* Allocate so it fits all events, there's a sanity check later */
>> +	event = kzalloc(128, GFP_KERNEL);
>> +	if (!event)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	e = drm_client_read_get_pending_event(dev, file);
>> +	if (IS_ERR(e)) {
>> +		ret = PTR_ERR(e);
>> +		goto err_free;
>> +	}
>> +
>> +	if (!e && !block) {
>> +		ret = 0;
>> +		goto err_free;
>> +	}
>> +
>> +	ret = wait_event_interruptible_timeout(file->event_wait,
>> +					       !list_empty(&file->event_list),
>> +					       5 * HZ);
>> +	if (!ret)
>> +		ret = -ETIMEDOUT;
>> +	if (ret < 0)
>> +		goto err_free;
>> +
>> +	e = drm_client_read_get_pending_event(dev, file);
>> +	if (IS_ERR_OR_NULL(e)) {
>> +		ret = PTR_ERR_OR_ZERO(e);
>> +		goto err_free;
>> +	}
>> +
>> +	if (WARN_ON(e->event->length > 128)) {
>> +		/* Increase buffer if this happens */
>> +		ret = -ENOMEM;
>> +		goto err_free;
>> +	}
>> +
>> +	memcpy(event, e->event, e->event->length);
>> +	kfree(e);
>> +
>> +	return event;
>> +
>> +err_free:
>> +	kfree(event);
>> +
>> +	return ret ? ERR_PTR(ret) : NULL;
>> +}
>> +EXPORT_SYMBOL(drm_client_read_event);
>> +
>> +static void drm_client_connector_free(struct drm_client_connector *connector)
>> +{
>> +	if (!connector)
>> +		return;
>> +	kfree(connector->modes);
>> +	kfree(connector);
>> +}
>> +
>> +static struct drm_client_connector *
>> +drm_client_get_connector(struct drm_client_dev *client, unsigned int id)
>> +{
>> +	struct drm_mode_get_connector req = {
>> +		.connector_id = id,
>> +	};
>> +	struct drm_client_connector *connector;
>> +	struct drm_mode_modeinfo *modes = NULL;
>> +	struct drm_device *dev = client->dev;
>> +	struct drm_connector *conn;
>> +	bool non_desktop;
>> +	int ret;
>> +
>> +	connector = kzalloc(sizeof(*connector), GFP_KERNEL);
>> +	if (!connector)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	ret = drm_mode_getconnector(dev, &req, client->file, false);
>> +	if (ret)
>> +		goto err_free;
>> +
>> +	connector->conn_id = id;
>> +	connector->status = req.connection;
>> +
>> +	conn = drm_connector_lookup(dev, client->file, id);
>> +	if (!conn) {
>> +		ret = -ENOENT;
>> +		goto err_free;
>> +	}
>> +
>> +	non_desktop = conn->display_info.non_desktop;
>> +
>> +	connector->has_tile = conn->has_tile;
>> +	connector->tile_h_loc = conn->tile_h_loc;
>> +	connector->tile_v_loc = conn->tile_v_loc;
>> +	if (conn->tile_group)
>> +		connector->tile_group = conn->tile_group->id;
>> +
>> +	drm_connector_put(conn);
>> +
>> +	if (non_desktop) {
>> +		kfree(connector);
>> +		return NULL;
>> +	}
>> +
>> +	if (!req.count_modes)
>> +		return connector;
>> +
>> +	modes = kcalloc(req.count_modes, sizeof(*modes), GFP_KERNEL);
>> +	if (!modes) {
>> +		ret = -ENOMEM;
>> +		goto err_free;
>> +	}
>> +
>> +	connector->modes = modes;
>> +	connector->num_modes = req.count_modes;
>> +
>> +	req.count_props = 0;
>> +	req.count_encoders = 0;
>> +	req.modes_ptr = (unsigned long)modes;
>> +
>> +	ret = drm_mode_getconnector(dev, &req, client->file, false);
>> +	if (ret)
>> +		goto err_free;
>> +
>> +	return connector;
>> +
>> +err_free:
>> +	kfree(modes);
>> +	kfree(connector);
>> +
>> +	return ERR_PTR(ret);
>> +}
>> +
>> +static int drm_client_get_connectors(struct drm_client_dev *client,
>> +				     struct drm_client_connector ***connectors)
>> +{
>> +	struct drm_mode_card_res card_res = {};
>> +	struct drm_device *dev = client->dev;
>> +	int ret, num_connectors;
>> +	u32 *connector_ids;
>> +	unsigned int i;
>> +
>> +	ret = drm_mode_getresources(dev, &card_res, client->file, false);
>> +	if (ret)
>> +		return ret;
>> +	if (!card_res.count_connectors)
>> +		return 0;
>> +
>> +	num_connectors = card_res.count_connectors;
>> +	connector_ids = kcalloc(num_connectors,
>> +				sizeof(*connector_ids), GFP_KERNEL);
>> +	if (!connector_ids)
>> +		return -ENOMEM;
>> +
>> +	card_res.count_fbs = 0;
>> +	card_res.count_crtcs = 0;
>> +	card_res.count_encoders = 0;
>> +	card_res.connector_id_ptr = (unsigned long)connector_ids;
>> +
>> +	ret = drm_mode_getresources(dev, &card_res, client->file, false);
>> +	if (ret)
>> +		goto err_free;
>> +
>> +	*connectors = kcalloc(num_connectors, sizeof(**connectors), GFP_KERNEL);
>> +	if (!(*connectors)) {
>> +		ret = -ENOMEM;
>> +		goto err_free;
>> +	}
>> +
>> +	for (i = 0; i < num_connectors; i++) {
>> +		struct drm_client_connector *connector;
>> +
>> +		connector = drm_client_get_connector(client, connector_ids[i]);
>> +		if (IS_ERR(connector)) {
>> +			ret = PTR_ERR(connector);
>> +			goto err_free;
>> +		}
>> +		if (connector)
>> +			(*connectors)[i] = connector;
>> +		else
>> +			num_connectors--;
>> +	}
>> +
>> +	if (!num_connectors) {
>> +		ret = 0;
>> +		goto err_free;
>> +	}
>> +
>> +	return num_connectors;
>> +
>> +err_free:
>> +	if (connectors)
>> +		for (i = 0; i < num_connectors; i++)
>> +			drm_client_connector_free((*connectors)[i]);
>> +
>> +	kfree(connectors);
>> +	kfree(connector_ids);
>> +
>> +	return ret;
>> +}
>> +
>> +static bool
>> +drm_client_connector_is_enabled(struct drm_client_connector *connector,
>> +				bool strict)
>> +{
>> +	if (strict)
>> +		return connector->status == connector_status_connected;
>> +	else
>> +		return connector->status != connector_status_disconnected;
>> +}
>> +
>> +struct drm_mode_modeinfo *
>> +drm_client_display_first_mode(struct drm_client_display *display)
>> +{
>> +	if (!display->num_modes)
>> +		return NULL;
>> +	return display->modes;
>> +}
>> +EXPORT_SYMBOL(drm_client_display_first_mode);
>> +
>> +struct drm_mode_modeinfo *
>> +drm_client_display_next_mode(struct drm_client_display *display,
>> +			     struct drm_mode_modeinfo *mode)
>> +{
>> +	struct drm_mode_modeinfo *modes = display->modes;
>> +
>> +	if (++mode < &modes[display->num_modes])
>> +		return mode;
>> +
>> +	return NULL;
>> +}
>> +EXPORT_SYMBOL(drm_client_display_next_mode);
>> +
>> +static void
>> +drm_client_display_fill_tile_modes(struct drm_client_display *display,
>> +				   struct drm_mode_modeinfo *tile_modes)
>> +{
>> +	unsigned int i, j, num_modes = display->connectors[0]->num_modes;
>> +	struct drm_mode_modeinfo *tile_mode, *conn_mode;
>> +
>> +	if (!num_modes) {
>> +		kfree(tile_modes);
>> +		kfree(display->modes);
>> +		display->modes = NULL;
>> +		display->num_modes = 0;
>> +		return;
>> +	}
>> +
>> +	for (i = 0; i < num_modes; i++) {
>> +		tile_mode = &tile_modes[i];
>> +
>> +		conn_mode = &display->connectors[0]->modes[i];
>> +		tile_mode->clock = conn_mode->clock;
>> +		tile_mode->vscan = conn_mode->vscan;
>> +		tile_mode->vrefresh = conn_mode->vrefresh;
>> +		tile_mode->flags = conn_mode->flags;
>> +		tile_mode->type = conn_mode->type;
>> +
>> +		for (j = 0; j < display->num_connectors; j++) {
>> +			conn_mode = &display->connectors[j]->modes[i];
>> +
>> +			if (!display->connectors[j]->tile_h_loc) {
>> +				tile_mode->hdisplay += conn_mode->hdisplay;
>> +				tile_mode->hsync_start += conn_mode->hsync_start;
>> +				tile_mode->hsync_end += conn_mode->hsync_end;
>> +				tile_mode->htotal += conn_mode->htotal;
>> +			}
>> +
>> +			if (!display->connectors[j]->tile_v_loc) {
>> +				tile_mode->vdisplay += conn_mode->vdisplay;
>> +				tile_mode->vsync_start += conn_mode->vsync_start;
>> +				tile_mode->vsync_end += conn_mode->vsync_end;
>> +				tile_mode->vtotal += conn_mode->vtotal;
>> +			}
>> +		}
>> +	}
>> +
>> +	kfree(display->modes);
>> +	display->modes = tile_modes;
>> +	display->num_modes = num_modes;
>> +}
>> +
>> +/**
>> + * drm_client_display_update_modes - Fetch display modes
>> + * @display: Client display
>> + * @mode_changed: Optional pointer to boolen which return whether the modes
>> + *                have changed or not.
>> + *
>> + * This function can be used in the client hotplug callback to check if the
>> + * video modes have changed and get them up-to-date.
>> + *
>> + * Returns:
>> + * Number of modes on success, negative error code on failure.
>> + */
>> +int drm_client_display_update_modes(struct drm_client_display *display,
>> +				    bool *mode_changed)
>> +{
>> +	unsigned int num_connectors = display->num_connectors;
>> +	struct drm_client_dev *client = display->client;
>> +	struct drm_mode_modeinfo *display_tile_modes;
>> +	struct drm_client_connector **connectors;
>> +	unsigned int i, num_modes = 0;
>> +	bool dummy_changed = false;
>> +	int ret;
>> +
>> +	if (mode_changed)
>> +		*mode_changed = false;
>> +	else
>> +		mode_changed = &dummy_changed;
>> +
>> +	if (display->cloned)
>> +		return 2;
>> +
>> +	ret = drm_client_get_file(client);
>> +	if (ret)
>> +		return ret;
>> +
>> +	connectors = kcalloc(num_connectors, sizeof(*connectors), GFP_KERNEL);
>> +	if (!connectors) {
>> +		ret = -ENOMEM;
>> +		goto out_put_file;
>> +	}
>> +
>> +	/* Get a new set for comparison */
>> +	for (i = 0; i < num_connectors; i++) {
>> +		connectors[i] = drm_client_get_connector(client, display->connectors[i]->conn_id);
>> +		if (IS_ERR_OR_NULL(connectors[i])) {
>> +			ret = PTR_ERR_OR_ZERO(connectors[i]);
>> +			if (!ret)
>> +				ret = -ENOENT;
>> +			goto out_cleanup;
>> +		}
>> +	}
>> +
>> +	/* All connectors should have the same number of modes */
>> +	num_modes = connectors[0]->num_modes;
>> +	for (i = 0; i < num_connectors; i++) {
>> +		if (num_modes != connectors[i]->num_modes) {
>> +			ret = -EINVAL;
>> +			goto out_cleanup;
>> +		}
>> +	}
>> +
>> +	if (num_connectors > 1) {
>> +		display_tile_modes = kcalloc(num_modes, sizeof(*display_tile_modes), GFP_KERNEL);
>> +		if (!display_tile_modes) {
>> +			ret = -ENOMEM;
>> +			goto out_cleanup;
>> +		}
>> +	}
>> +
>> +	mutex_lock(&display->modes_lock);
>> +
>> +	for (i = 0; i < num_connectors; i++) {
>> +		display->connectors[i]->status = connectors[i]->status;
>> +		if (display->connectors[i]->num_modes != connectors[i]->num_modes) {
>> +			display->connectors[i]->num_modes = connectors[i]->num_modes;
>> +			kfree(display->connectors[i]->modes);
>> +			display->connectors[i]->modes = connectors[i]->modes;
>> +			connectors[i]->modes = NULL;
>> +			*mode_changed = true;
>> +		}
>> +	}
>> +
>> +	if (num_connectors > 1)
>> +		drm_client_display_fill_tile_modes(display, display_tile_modes);
>> +	else
>> +		display->modes = display->connectors[0]->modes;
>> +
>> +	mutex_unlock(&display->modes_lock);
>> +
>> +out_cleanup:
>> +	for (i = 0; i < num_connectors; i++)
>> +		drm_client_connector_free(connectors[i]);
>> +	kfree(connectors);
>> +out_put_file:
>> +	drm_client_put_file(client);
>> +
>> +	return ret ? ret : num_modes;
>> +}
>> +EXPORT_SYMBOL(drm_client_display_update_modes);
>> +
>> +void drm_client_display_free(struct drm_client_display *display)
>> +{
>> +	unsigned int i;
>> +
>> +	if (!display)
>> +		return;
>> +
>> +	/* tile modes? */
>> +	if (display->modes != display->connectors[0]->modes)
>> +		kfree(display->modes);
>> +
>> +	for (i = 0; i < display->num_connectors; i++)
>> +		drm_client_connector_free(display->connectors[i]);
>> +
>> +	kfree(display->connectors);
>> +	mutex_destroy(&display->modes_lock);
>> +	kfree(display);
>> +}
>> +EXPORT_SYMBOL(drm_client_display_free);
>> +
>> +static struct drm_client_display *
>> +drm_client_display_alloc(struct drm_client_dev *client,
>> +			 unsigned int num_connectors)
>> +{
>> +	struct drm_client_display *display;
>> +	struct drm_client_connector **connectors;
>> +
>> +	display = kzalloc(sizeof(*display), GFP_KERNEL);
>> +	connectors = kcalloc(num_connectors, sizeof(*connectors), GFP_KERNEL);
>> +	if (!display || !connectors) {
>> +		kfree(display);
>> +		kfree(connectors);
>> +		return NULL;
>> +	}
>> +
>> +	mutex_init(&display->modes_lock);
>> +	display->client = client;
>> +	display->connectors = connectors;
>> +	display->num_connectors = num_connectors;
>> +
>> +	return display;
>> +}
>> +
>> +/* Logic is from drm_fb_helper */
>> +static struct drm_client_display *
>> +drm_client_connector_pick_cloned(struct drm_client_dev *client,
>> +				 struct drm_client_connector **connectors,
>> +				 unsigned int num_connectors)
>> +{
>> +	struct drm_mode_modeinfo modes[2], udmt_mode, *mode, *tmp;
>> +	struct drm_display_mode *dmt_display_mode = NULL;
>> +	unsigned int i, j, conns[2], num_conns = 0;
>> +	struct drm_client_connector *connector;
>> +	struct drm_device *dev = client->dev;
>> +	struct drm_client_display *display;
>> +
>> +	/* only contemplate cloning in the single crtc case */
>> +	if (dev->mode_config.num_crtc > 1)
>> +		return NULL;
>> +retry:
>> +	for (i = 0; i < num_connectors; i++) {
>> +		connector = connectors[i];
>> +		if (!connector || connector->has_tile || !connector->num_modes)
>> +			continue;
>> +
>> +		for (j = 0; j < connector->num_modes; j++) {
>> +			mode = &connector->modes[j];
>> +			if (dmt_display_mode) {
>> +				if (drm_umode_equal(&udmt_mode, mode)) {
>> +					conns[num_conns] = i;
>> +					modes[num_conns++] = *mode;
>> +					break;
>> +				}
>> +			} else {
>> +				if (mode->type & DRM_MODE_TYPE_USERDEF) {
>> +					conns[num_conns] = i;
>> +					modes[num_conns++] = *mode;
>> +					break;
>> +				}
>> +			}
>> +		}
>> +		if (num_conns == 2)
>> +			break;
>> +	}
>> +
>> +	if (num_conns == 2)
>> +		goto found;
>> +
>> +	if (dmt_display_mode)
>> +		return NULL;
>> +
>> +	dmt_display_mode = drm_mode_find_dmt(dev, 1024, 768, 60, false);
>> +	drm_mode_convert_to_umode(&udmt_mode, dmt_display_mode);
>> +	drm_mode_destroy(dev, dmt_display_mode);
>> +
>> +	goto retry;
>> +
>> +found:
>> +	tmp = kcalloc(2, sizeof(*tmp), GFP_KERNEL);
>> +	if (!tmp)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	display = drm_client_display_alloc(client, 2);
>> +	if (!display) {
>> +		kfree(tmp);
>> +		return ERR_PTR(-ENOMEM);
>> +	}
>> +
>> +	for (i = 0; i < 2; i++) {
>> +		connector = connectors[conns[i]];
>> +		display->connectors[i] = connector;
>> +		connectors[conns[i]] = NULL;
>> +		kfree(connector->modes);
>> +		tmp[i] = modes[i];
>> +		connector->modes = &tmp[i];
>> +		connector->num_modes = 1;
>> +	}
>> +
>> +	display->cloned = true;
>> +	display->modes = &tmp[0];
>> +	display->num_modes = 1;
>> +
>> +	return display;
>> +}
>> +
>> +static struct drm_client_display *
>> +drm_client_connector_pick_tile(struct drm_client_dev *client,
>> +			       struct drm_client_connector **connectors,
>> +			       unsigned int num_connectors)
>> +{
>> +	unsigned int i, num_conns, num_modes, tile_group = 0;
>> +	struct drm_mode_modeinfo *tile_modes = NULL;
>> +	struct drm_client_connector *connector;
>> +	struct drm_client_display *display;
>> +	u16 conns[32];
>> +
>> +	for (i = 0; i < num_connectors; i++) {
>> +		connector = connectors[i];
>> +		if (!connector || !connector->tile_group)
>> +			continue;
>> +
>> +		if (!tile_group) {
>> +			tile_group = connector->tile_group;
>> +			num_modes = connector->num_modes;
>> +		}
>> +
>> +		if (connector->tile_group != tile_group)
>> +			continue;
>> +
>> +		if (num_modes != connector->num_modes) {
>> +			DRM_ERROR("Tile connectors must have the same number of modes\n");
>> +			return ERR_PTR(-EINVAL);
>> +		}
>> +
>> +		conns[num_conns++] = i;
>> +		if (WARN_ON(num_conns == 33))
>> +			return ERR_PTR(-EINVAL);
>> +	}
>> +
>> +	if (!num_conns)
>> +		return NULL;
>> +
>> +	if (num_modes) {
>> +		tile_modes = kcalloc(num_modes, sizeof(*tile_modes), GFP_KERNEL);
>> +		if (!tile_modes)
>> +			return ERR_PTR(-ENOMEM);
>> +	}
>> +
>> +	display = drm_client_display_alloc(client, num_conns);
>> +	if (!display) {
>> +		kfree(tile_modes);
>> +		return ERR_PTR(-ENOMEM);
>> +	}
>> +
>> +	if (num_modes)
>> +		drm_client_display_fill_tile_modes(display, tile_modes);
>> +
>> +	return display;
>> +}
>> +
>> +static struct drm_client_display *
>> +drm_client_connector_pick_not_tile(struct drm_client_dev *client,
>> +				   struct drm_client_connector **connectors,
>> +				   unsigned int num_connectors)
>> +{
>> +	struct drm_client_display *display;
>> +	unsigned int i;
>> +
>> +	for (i = 0; i < num_connectors; i++) {
>> +		if (!connectors[i] || connectors[i]->has_tile)
>> +			continue;
>> +		break;
>> +	}
>> +
>> +	if (i == num_connectors)
>> +		return NULL;
>> +
>> +	display = drm_client_display_alloc(client, 1);
>> +	if (!display)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	display->connectors[0] = connectors[i];
>> +	connectors[i] = NULL;
>> +	display->modes = display->connectors[0]->modes;
>> +	display->num_modes = display->connectors[0]->num_modes;
>> +
>> +	return display;
>> +}
>> +
>> +/* Get connectors and bundle them up into displays */
>> +static int drm_client_get_displays(struct drm_client_dev *client,
>> +				   struct drm_client_display ***displays)
>> +{
>> +	int ret, num_connectors, num_displays = 0;
>> +	struct drm_client_connector **connectors;
>> +	struct drm_client_display *display;
>> +	unsigned int i;
>> +
>> +	ret = drm_client_get_file(client);
>> +	if (ret)
>> +		return ret;
>> +
>> +	num_connectors = drm_client_get_connectors(client, &connectors);
>> +	if (num_connectors <= 0) {
>> +		ret = num_connectors;
>> +		goto err_put_file;
>> +	}
>> +
>> +	*displays = kcalloc(num_connectors, sizeof(*displays), GFP_KERNEL);
>> +	if (!(*displays)) {
>> +		ret = -ENOMEM;
>> +		goto err_free;
>> +	}
>> +
>> +	display = drm_client_connector_pick_cloned(client, connectors,
>> +						   num_connectors);
>> +	if (IS_ERR(display)) {
>> +		ret = PTR_ERR(display);
>> +		goto err_free;
>> +	}
>> +	if (display)
>> +		(*displays)[num_displays++] = display;
>> +
>> +	for (i = 0; i < num_connectors; i++) {
>> +		display = drm_client_connector_pick_tile(client, connectors,
>> +							 num_connectors);
>> +		if (IS_ERR(display)) {
>> +			ret = PTR_ERR(display);
>> +			goto err_free;
>> +		}
>> +		if (!display)
>> +			break;
>> +		(*displays)[num_displays++] = display;
>> +	}
>> +
>> +	for (i = 0; i < num_connectors; i++) {
>> +		display = drm_client_connector_pick_not_tile(client, connectors,
>> +							     num_connectors);
>> +		if (IS_ERR(display)) {
>> +			ret = PTR_ERR(display);
>> +			goto err_free;
>> +		}
>> +		if (!display)
>> +			break;
>> +		(*displays)[num_displays++] = display;
>> +	}
>> +
>> +	for (i = 0; i < num_connectors; i++) {
>> +		if (connectors[i]) {
>> +			DRM_INFO("Connector %u fell through the cracks.\n",
>> +				 connectors[i]->conn_id);
>> +			drm_client_connector_free(connectors[i]);
>> +		}
>> +	}
>> +
>> +	drm_client_put_file(client);
>> +	kfree(connectors);
>> +
>> +	return num_displays;
>> +
>> +err_free:
>> +	for (i = 0; i < num_displays; i++)
>> +		drm_client_display_free((*displays)[i]);
>> +	kfree(*displays);
>> +	*displays = NULL;
>> +	for (i = 0; i < num_connectors; i++)
>> +		drm_client_connector_free(connectors[i]);
>> +	kfree(connectors);
>> +err_put_file:
>> +	drm_client_put_file(client);
>> +
>> +	return ret;
>> +}
>> +
>> +static bool
>> +drm_client_display_is_enabled(struct drm_client_display *display, bool strict)
>> +{
>> +	unsigned int i;
>> +
>> +	if (!display->num_modes)
>> +		return false;
>> +
>> +	for (i = 0; i < display->num_connectors; i++)
>> +		if (!drm_client_connector_is_enabled(display->connectors[i], strict))
>> +			return false;
>> +
>> +	return true;
>> +}
>> +
>> +/**
>> + * drm_client_display_get_first_enabled - Get first enabled display
>> + * @client: DRM client
>> + * @strict: If true the connector(s) have to be connected, if false they can
>> + *          also have unknown status.
>> + *
>> + * This function gets all connectors and bundles them into displays
>> + * (tiled/cloned). It then picks the first one with connectors that is enabled
>> + * according to @strict.
>> + *
>> + * Returns:
>> + * Pointer to a client display if such a display was found, NULL if not found
>> + * or an error pointer on failure.
>> + */
>> +struct drm_client_display *
>> +drm_client_display_get_first_enabled(struct drm_client_dev *client, bool strict)
>> +{
>> +	struct drm_client_display **displays, *display = NULL;
>> +	int num_displays;
>> +	unsigned int i;
>> +
>> +	num_displays = drm_client_get_displays(client, &displays);
>> +	if (num_displays < 0)
>> +		return ERR_PTR(num_displays);
>> +	if (!num_displays)
>> +		return NULL;
>> +
>> +	for (i = 0; i < num_displays; i++) {
>> +		if (!display &&
>> +		    drm_client_display_is_enabled(displays[i], strict)) {
>> +			display = displays[i];
>> +			continue;
>> +		}
>> +		drm_client_display_free(displays[i]);
>> +	}
>> +
>> +	kfree(displays);
>> +
>> +	return display;
>> +}
>> +EXPORT_SYMBOL(drm_client_display_get_first_enabled);
>> +
>> +unsigned int
>> +drm_client_display_preferred_depth(struct drm_client_display *display)
>> +{
>> +	struct drm_connector *conn;
>> +	unsigned int ret;
>> +
>> +	conn = drm_connector_lookup(display->client->dev, NULL,
>> +				    display->connectors[0]->conn_id);
>> +	if (!conn)
>> +		return 0;
>> +
>> +	if (conn->cmdline_mode.bpp_specified)
>> +		ret = conn->cmdline_mode.bpp;
>> +	else
>> +		ret = display->client->dev->mode_config.preferred_depth;
>> +
>> +	drm_connector_put(conn);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL(drm_client_display_preferred_depth);
>> +
>> +int drm_client_display_dpms(struct drm_client_display *display, int mode)
>> +{
>> +	struct drm_mode_obj_set_property prop;
>> +
>> +	prop.value = mode;
>> +	prop.prop_id = display->client->dev->mode_config.dpms_property->base.id;
>> +	prop.obj_id = display->connectors[0]->conn_id;
>> +	prop.obj_type = DRM_MODE_OBJECT_CONNECTOR;
>> +
>> +	return drm_mode_obj_set_property(display->client->dev, &prop,
>> +					 display->client->file);
>> +}
>> +EXPORT_SYMBOL(drm_client_display_dpms);
>> +
>> +int drm_client_display_wait_vblank(struct drm_client_display *display)
>> +{
>> +	struct drm_crtc *crtc;
>> +	union drm_wait_vblank vblank_req = {
>> +		.request = {
>> +			.type = _DRM_VBLANK_RELATIVE,
>> +			.sequence = 1,
>> +		},
>> +	};
>> +
>> +	crtc = drm_crtc_find(display->client->dev, display->client->file,
>> +			     display->connectors[0]->crtc_id);
>> +	if (!crtc)
>> +		return -ENOENT;
>> +
>> +	vblank_req.request.type |= drm_crtc_index(crtc) << _DRM_VBLANK_HIGH_CRTC_SHIFT;
>> +
>> +	return drm_wait_vblank(display->client->dev, &vblank_req,
>> +			       display->client->file);
>> +}
>> +EXPORT_SYMBOL(drm_client_display_wait_vblank);
>> +
>> +static int drm_client_get_crtc_index(struct drm_client_dev *client, u32 id)
>> +{
>> +	int i;
>> +
>> +	for (i = 0; i < client->num_crtcs; i++)
>> +		if (client->crtcs[i] == id)
>> +			return i;
>> +
>> +	return -ENOENT;
>> +}
>> +
>> +static int drm_client_display_find_crtcs(struct drm_client_display *display)
>> +{
>> +	struct drm_client_dev *client = display->client;
>> +	struct drm_device *dev = client->dev;
>> +	struct drm_file *file = client->file;
>> +	u32 encoder_ids[DRM_CONNECTOR_MAX_ENCODER];
>> +	unsigned int i, j, available_crtcs = ~0;
>> +	struct drm_mode_get_connector conn_req;
>> +	struct drm_mode_get_encoder enc_req;
>> +	int ret;
>> +
>> +	/* Already done? */
>> +	if (display->connectors[0]->crtc_id)
>> +		return 0;
>> +
>> +	for (i = 0; i < display->num_connectors; i++) {
>> +		u32 active_crtcs = 0, crtcs_for_connector = 0;
>> +		int crtc_idx;
>> +
>> +		memset(&conn_req, 0, sizeof(conn_req));
>> +		conn_req.connector_id = display->connectors[i]->conn_id;
>> +		conn_req.encoders_ptr = (unsigned long)(encoder_ids);
>> +		conn_req.count_encoders = DRM_CONNECTOR_MAX_ENCODER;
>> +		ret = drm_mode_getconnector(dev, &conn_req, file, false);
>> +		if (ret)
>> +			return ret;
>> +
>> +		if (conn_req.encoder_id) {
>> +			memset(&enc_req, 0, sizeof(enc_req));
>> +			enc_req.encoder_id = conn_req.encoder_id;
>> +			ret = drm_mode_getencoder(dev, &enc_req, file);
>> +			if (ret)
>> +				return ret;
>> +			crtcs_for_connector |= enc_req.possible_crtcs;
>> +			if (crtcs_for_connector & available_crtcs)
>> +				goto found;
>> +		}
>> +
>> +		for (j = 0; j < conn_req.count_encoders; j++) {
>> +			memset(&enc_req, 0, sizeof(enc_req));
>> +			enc_req.encoder_id = encoder_ids[j];
>> +			ret = drm_mode_getencoder(dev, &enc_req, file);
>> +			if (ret)
>> +				return ret;
>> +
>> +			crtcs_for_connector |= enc_req.possible_crtcs;
>> +
>> +			if (enc_req.crtc_id) {
>> +				crtc_idx = drm_client_get_crtc_index(client, enc_req.crtc_id);
>> +				if (crtc_idx >= 0)
>> +					active_crtcs |= 1 << crtc_idx;
>> +			}
>> +		}
>> +
>> +found:
>> +		crtcs_for_connector &= available_crtcs;
>> +		active_crtcs &= available_crtcs;
>> +
>> +		if (!crtcs_for_connector)
>> +			return -ENOENT;
>> +
>> +		if (active_crtcs)
>> +			crtc_idx = ffs(active_crtcs) - 1;
>> +		else
>> +			crtc_idx = ffs(crtcs_for_connector) - 1;
>> +
>> +		if (crtc_idx >= client->num_crtcs)
>> +			return -EINVAL;
>> +
>> +		display->connectors[i]->crtc_id = client->crtcs[crtc_idx];
>> +		available_crtcs &= ~BIT(crtc_idx);
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +/**
>> + * drm_client_display_commit_mode - Commit a mode to the crtc(s)
>> + * @display: Client display
>> + * @fb_id: Framebuffer id
>> + * @mode: Video mode
>> + *
>> + * Returns:
>> + * Zero on success, negative error code on failure.
>> + */
>> +int drm_client_display_commit_mode(struct drm_client_display *display,
>> +				   u32 fb_id, struct drm_mode_modeinfo *mode)
>> +{
>> +	struct drm_client_dev *client = display->client;
>> +	struct drm_device *dev = client->dev;
>> +	unsigned int num_crtcs = client->num_crtcs;
>> +	struct drm_file *file = client->file;
>> +	unsigned int *xoffsets = NULL, *yoffsets = NULL;
>> +	struct drm_mode_crtc *crtc_reqs, *req;
>> +	u32 cloned_conn_ids[2];
>> +	unsigned int i;
>> +	int idx, ret;
>> +
>> +	ret = drm_client_display_find_crtcs(display);
>> +	if (ret)
>> +		return ret;
>> +
>> +	crtc_reqs = kcalloc(num_crtcs, sizeof(*crtc_reqs), GFP_KERNEL);
>> +	if (!crtc_reqs)
>> +		return -ENOMEM;
>> +
>> +	for (i = 0; i < num_crtcs; i++)
>> +		crtc_reqs[i].crtc_id = client->crtcs[i];
>> +
>> +	if (drm_client_display_is_tiled(display)) {
>> +		/* TODO calculate tile crtc offsets */
>> +	}
>> +
>> +	for (i = 0; i < display->num_connectors; i++) {
>> +		idx = drm_client_get_crtc_index(client, display->connectors[i]->crtc_id);
>> +		if (idx < 0)
>> +			return -ENOENT;
>> +
>> +		req = &crtc_reqs[idx];
>> +
>> +		req->fb_id = fb_id;
>> +		if (xoffsets) {
>> +			req->x = xoffsets[i];
>> +			req->y = yoffsets[i];
>> +		}
>> +		req->mode_valid = 1;
>> +		req->mode = *mode;
>> +
>> +		if (display->cloned) {
>> +			cloned_conn_ids[0] = display->connectors[0]->conn_id;
>> +			cloned_conn_ids[1] = display->connectors[1]->conn_id;
>> +			req->set_connectors_ptr = (unsigned long)(cloned_conn_ids);
>> +			req->count_connectors = 2;
>> +			break;
>> +		}
>> +
>> +		req->set_connectors_ptr = (unsigned long)(&display->connectors[i]->conn_id);
>> +		req->count_connectors = 1;
>> +	}
>> +
>> +	for (i = 0; i < num_crtcs; i++) {
>> +		ret = drm_mode_setcrtc(dev, &crtc_reqs[i], file, false);
>> +		if (ret)
>> +			break;
>> +	}
>> +
>> +	kfree(xoffsets);
>> +	kfree(yoffsets);
>> +	kfree(crtc_reqs);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL(drm_client_display_commit_mode);
>> +
>> +unsigned int drm_client_display_current_fb(struct drm_client_display *display)
>> +{
>> +	struct drm_client_dev *client = display->client;
>> +	int ret;
>> +	struct drm_mode_crtc crtc_req = {
>> +		.crtc_id = display->connectors[0]->crtc_id,
>> +	};
>> +
>> +	ret = drm_mode_getcrtc(client->dev, &crtc_req, client->file);
>> +	if (ret)
>> +		return 0;
>> +
>> +	return crtc_req.fb_id;
>> +}
>> +EXPORT_SYMBOL(drm_client_display_current_fb);
>> +
>> +int drm_client_display_flush(struct drm_client_display *display, u32 fb_id,
>> +			     struct drm_clip_rect *clips, unsigned int num_clips)
>> +{
>> +	struct drm_client_dev *client = display->client;
>> +	struct drm_mode_fb_dirty_cmd dirty_req = {
>> +		.fb_id = fb_id,
>> +		.clips_ptr = (unsigned long)clips,
>> +		.num_clips = num_clips,
>> +	};
>> +	int ret;
>> +
>> +	if (display->no_flushing)
>> +		return 0;
>> +
>> +	ret = drm_mode_dirtyfb(client->dev, &dirty_req, client->file, false);
>> +	if (ret == -ENOSYS) {
>> +		ret = 0;
>> +		display->no_flushing = true;
>> +	}
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL(drm_client_display_flush);
>> +
>> +int drm_client_display_page_flip(struct drm_client_display *display, u32 fb_id,
>> +				 bool event)
>> +{
>> +	struct drm_client_dev *client = display->client;
>> +	struct drm_mode_crtc_page_flip_target page_flip_req = {
>> +		.crtc_id = display->connectors[0]->crtc_id,
>> +		.fb_id = fb_id,
>> +	};
>> +
>> +	if (event)
>> +		page_flip_req.flags = DRM_MODE_PAGE_FLIP_EVENT;
>> +
>> +	return drm_mode_page_flip(client->dev, &page_flip_req, client->file);
>> +	/*
>> +	 * TODO:
>> +	 * Where do we flush on page flip? Should the driver handle that?
>> +	 */
>> +}
>> +EXPORT_SYMBOL(drm_client_display_page_flip);
>> +
>> +/**
>> + * drm_client_framebuffer_create - Create a client framebuffer
>> + * @client: DRM client
>> + * @mode: Display mode to create a buffer for
>> + * @format: Buffer format
>> + *
>> + * This function creates a &drm_client_buffer which consists of a
>> + * &drm_framebuffer backed by a dumb buffer. The dumb buffer is &dma_buf
>> + * exported to aquire a virtual address which is stored in
>> + * &drm_client_buffer->vaddr.
>> + * Call drm_client_framebuffer_delete() to free the buffer.
>> + *
>> + * Returns:
>> + * Pointer to a client buffer or an error pointer on failure.
>> + */
>> +struct drm_client_buffer *
>> +drm_client_framebuffer_create(struct drm_client_dev *client,
>> +			      struct drm_mode_modeinfo *mode, u32 format)
>> +{
>> +	struct drm_client_buffer *buffer;
>> +	int ret;
>> +
>> +	buffer = drm_client_buffer_create(client, mode->hdisplay,
>> +					  mode->vdisplay, format);
>> +	if (IS_ERR(buffer))
>> +		return buffer;
>> +
>> +	ret = drm_client_buffer_addfb(buffer, mode);
>> +	if (ret) {
>> +		drm_client_buffer_delete(buffer);
>> +		return ERR_PTR(ret);
>> +	}
>> +
>> +	return buffer;
>> +}
>> +EXPORT_SYMBOL(drm_client_framebuffer_create);
>> +
>> +void drm_client_framebuffer_delete(struct drm_client_buffer *buffer)
>> +{
>> +	drm_client_buffer_rmfb(buffer);
>> +	drm_client_buffer_delete(buffer);
>> +}
>> +EXPORT_SYMBOL(drm_client_framebuffer_delete);
>> +
>> +struct drm_client_buffer *
>> +drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height,
>> +			 u32 format)
>> +{
>> +	struct drm_mode_create_dumb dumb_args = { 0 };
>> +	struct drm_prime_handle prime_args = { 0 };
>> +	struct drm_client_buffer *buffer;
>> +	struct dma_buf *dma_buf;
>> +	void *vaddr;
>> +	int ret;
>> +
>> +	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
>> +	if (!buffer)
>> +		return ERR_PTR(-ENOMEM);
>> +
>> +	ret = drm_client_get_file(client);
>> +	if (ret)
>> +		goto err_free;
>> +
>> +	buffer->client = client;
>> +	buffer->width = width;
>> +	buffer->height = height;
>> +	buffer->format = format;
>> +
>> +	dumb_args.width = buffer->width;
>> +	dumb_args.height = buffer->height;
>> +	dumb_args.bpp = drm_format_plane_cpp(format, 0) * 8;
>> +	ret = drm_mode_create_dumb(client->dev, &dumb_args, client->file);
>> +	if (ret)
>> +		goto err_put_file;
>> +
>> +	buffer->handle = dumb_args.handle;
>> +	buffer->pitch = dumb_args.pitch;
>> +	buffer->size = dumb_args.size;
>> +
>> +	prime_args.handle = dumb_args.handle;
>> +	ret = drm_prime_handle_to_fd(client->dev, &prime_args, client->file);
>> +	if (ret)
>> +		goto err_delete;
>> +
>> +	dma_buf = dma_buf_get(prime_args.fd);
>> +	if (IS_ERR(dma_buf)) {
>> +		ret = PTR_ERR(dma_buf);
>> +		goto err_delete;
>> +	}
>> +
>> +	buffer->dma_buf = dma_buf;
>> +
>> +	vaddr = dma_buf_vmap(dma_buf);
>> +	if (!vaddr) {
>> +		ret = -ENOMEM;
>> +		goto err_delete;
>> +	}
>> +
>> +	buffer->vaddr = vaddr;
>> +
>> +	return buffer;
>> +
>> +err_delete:
>> +	drm_client_buffer_delete(buffer);
>> +err_put_file:
>> +	drm_client_put_file(client);
>> +err_free:
>> +	kfree(buffer);
>> +
>> +	return ERR_PTR(ret);
>> +}
>> +EXPORT_SYMBOL(drm_client_buffer_create);
>> +
>> +void drm_client_buffer_delete(struct drm_client_buffer *buffer)
>> +{
>> +	if (!buffer)
>> +		return;
>> +
>> +	if (buffer->vaddr)
>> +		dma_buf_vunmap(buffer->dma_buf, buffer->vaddr);
>> +
>> +	if (buffer->dma_buf)
>> +		dma_buf_put(buffer->dma_buf);
>> +
>> +	drm_mode_destroy_dumb(buffer->client->dev, buffer->handle,
>> +			      buffer->client->file);
>> +	drm_client_put_file(buffer->client);
>> +	kfree(buffer);
>> +}
>> +EXPORT_SYMBOL(drm_client_buffer_delete);
>> +
>> +int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
>> +			    struct drm_mode_modeinfo *mode)
>> +{
>> +	struct drm_client_dev *client = buffer->client;
>> +	struct drm_mode_fb_cmd2 fb_req = { };
>> +	unsigned int num_fbs, *fb_ids;
>> +	int i, ret;
>> +
>> +	if (buffer->num_fbs)
>> +		return -EINVAL;
>> +
>> +	if (mode->hdisplay > buffer->width || mode->vdisplay > buffer->height)
>> +		return -EINVAL;
>> +
>> +	num_fbs = buffer->height / mode->vdisplay;
>> +	fb_ids = kcalloc(num_fbs, sizeof(*fb_ids), GFP_KERNEL);
>> +	if (!fb_ids)
>> +		return -ENOMEM;
>> +
>> +	fb_req.width = mode->hdisplay;
>> +	fb_req.height = mode->vdisplay;
>> +	fb_req.pixel_format = buffer->format;
>> +	fb_req.handles[0] = buffer->handle;
>> +	fb_req.pitches[0] = buffer->pitch;
>> +
>> +	for (i = 0; i < num_fbs; i++) {
>> +		fb_req.offsets[0] = i * mode->vdisplay * buffer->pitch;
>> +		ret = drm_mode_addfb2(client->dev, &fb_req, client->file,
>> +				      client->funcs->name);
>> +		if (ret)
>> +			goto err_remove;
>> +		fb_ids[i] = fb_req.fb_id;
>> +	}
>> +
>> +	buffer->fb_ids = fb_ids;
>> +	buffer->num_fbs = num_fbs;
>> +
>> +	return 0;
>> +
>> +err_remove:
>> +	for (i--; i >= 0; i--)
>> +		drm_mode_rmfb(client->dev, fb_ids[i], client->file);
>> +	kfree(fb_ids);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL(drm_client_buffer_addfb);
>> +
>> +int drm_client_buffer_rmfb(struct drm_client_buffer *buffer)
>> +{
>> +	unsigned int i;
>> +	int ret;
>> +
>> +	if (!buffer || !buffer->num_fbs)
>> +		return 0;
>> +
>> +	for (i = 0; i < buffer->num_fbs; i++) {
>> +		ret = drm_mode_rmfb(buffer->client->dev, buffer->fb_ids[i],
>> +				    buffer->client->file);
>> +		if (ret)
>> +			DRM_DEV_ERROR(buffer->client->dev->dev,
>> +				      "Error removing FB:%u (%d)\n",
>> +				      buffer->fb_ids[i], ret);
>> +	}
>> +
>> +	kfree(buffer->fb_ids);
>> +	buffer->fb_ids = NULL;
>> +	buffer->num_fbs = 0;
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL(drm_client_buffer_rmfb);
>> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
>> index f869de185986..db161337d87c 100644
>> --- a/drivers/gpu/drm/drm_drv.c
>> +++ b/drivers/gpu/drm/drm_drv.c
>> @@ -33,6 +33,7 @@
>>   #include <linux/mount.h>
>>   #include <linux/slab.h>
>>   
>> +#include <drm/drm_client.h>
>>   #include <drm/drm_drv.h>
>>   #include <drm/drmP.h>
>>   
>> @@ -463,6 +464,7 @@ int drm_dev_init(struct drm_device *dev,
>>   	dev->driver = driver;
>>   
>>   	INIT_LIST_HEAD(&dev->filelist);
>> +	INIT_LIST_HEAD(&dev->filelist_internal);
>>   	INIT_LIST_HEAD(&dev->ctxlist);
>>   	INIT_LIST_HEAD(&dev->vmalist);
>>   	INIT_LIST_HEAD(&dev->maplist);
>> @@ -787,6 +789,8 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags)
>>   		 dev->dev ? dev_name(dev->dev) : "virtual device",
>>   		 dev->primary->index);
>>   
>> +	drm_client_dev_register(dev);
>> +
>>   	goto out_unlock;
>>   
>>   err_minors:
>> @@ -839,6 +843,8 @@ void drm_dev_unregister(struct drm_device *dev)
>>   	drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
>>   	drm_minor_unregister(dev, DRM_MINOR_RENDER);
>>   	drm_minor_unregister(dev, DRM_MINOR_CONTROL);
>> +
>> +	drm_client_dev_unregister(dev);
>>   }
>>   EXPORT_SYMBOL(drm_dev_unregister);
>>   
>> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
>> index 55505378df47..bcc688e58776 100644
>> --- a/drivers/gpu/drm/drm_file.c
>> +++ b/drivers/gpu/drm/drm_file.c
>> @@ -35,6 +35,7 @@
>>   #include <linux/slab.h>
>>   #include <linux/module.h>
>>   
>> +#include <drm/drm_client.h>
>>   #include <drm/drm_file.h>
>>   #include <drm/drmP.h>
>>   
>> @@ -443,6 +444,8 @@ void drm_lastclose(struct drm_device * dev)
>>   
>>   	if (drm_core_check_feature(dev, DRIVER_LEGACY))
>>   		drm_legacy_dev_reinit(dev);
>> +
>> +	drm_client_dev_lastclose(dev);
>>   }
>>   
>>   /**
>> diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
>> index 2d1643bdae78..5d2a6c6717f5 100644
>> --- a/drivers/gpu/drm/drm_probe_helper.c
>> +++ b/drivers/gpu/drm/drm_probe_helper.c
>> @@ -33,6 +33,7 @@
>>   #include <linux/moduleparam.h>
>>   
>>   #include <drm/drmP.h>
>> +#include <drm/drm_client.h>
>>   #include <drm/drm_crtc.h>
>>   #include <drm/drm_fourcc.h>
>>   #include <drm/drm_crtc_helper.h>
>> @@ -563,6 +564,8 @@ void drm_kms_helper_hotplug_event(struct drm_device *dev)
>>   	drm_sysfs_hotplug_event(dev);
>>   	if (dev->mode_config.funcs->output_poll_changed)
>>   		dev->mode_config.funcs->output_poll_changed(dev);
>> +
>> +	drm_client_dev_hotplug(dev);
>>   }
>>   EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
>>   
>> diff --git a/include/drm/drm_client.h b/include/drm/drm_client.h
>> new file mode 100644
>> index 000000000000..88f6f87919c5
>> --- /dev/null
>> +++ b/include/drm/drm_client.h
>> @@ -0,0 +1,192 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +
>> +#include <linux/mutex.h>
>> +
>> +struct dma_buf;
>> +struct drm_clip_rect;
>> +struct drm_device;
>> +struct drm_file;
>> +struct drm_mode_modeinfo;
>> +
>> +struct drm_client_dev;
>> +
>> +/**
>> + * struct drm_client_funcs - DRM client  callbacks
>> + */
>> +struct drm_client_funcs {
>> +	/**
>> +	 * @name:
>> +	 *
>> +	 * Name of the client.
>> +	 */
>> +	const char *name;
>> +
>> +	/**
>> +	 * @new:
>> +	 *
>> +	 * Called when a client or a &drm_device is registered.
>> +	 * If the callback returns anything but zero, then this client instance
>> +	 * is dropped.
>> +	 *
>> +	 * This callback is mandatory.
>> +	 */
>> +	int (*new)(struct drm_client_dev *client);
>> +
>> +	/**
>> +	 * @remove:
>> +	 *
>> +	 * Called when a &drm_device is unregistered or the client is
>> +	 * unregistered. If zero is returned drm_client_free() is called
>> +	 * automatically. If the client can't drop it's resources it should
>> +	 * return non-zero and call drm_client_free() later.
>> +	 *
>> +	 * This callback is optional.
>> +	 */
>> +	int (*remove)(struct drm_client_dev *client);
>> +
>> +	/**
>> +	 * @lastclose:
>> +	 *
>> +	 * Called on drm_lastclose(). The first client instance in the list
>> +	 * that returns zero gets the privilege to restore and no more clients
>> +	 * are called.
>> +	 *
>> +	 * This callback is optional.
>> +	 */
>> +	int (*lastclose)(struct drm_client_dev *client);
>> +
>> +	/**
>> +	 * @hotplug:
>> +	 *
>> +	 * Called on drm_kms_helper_hotplug_event().
>> +	 *
>> +	 * This callback is optional.
>> +	 */
>> +	int (*hotplug)(struct drm_client_dev *client);
>> +
>> +// TODO
>> +//	void (*suspend)(struct drm_client_dev *client);
>> +//	void (*resume)(struct drm_client_dev *client);
>> +};
>> +
>> +/**
>> + * struct drm_client_dev - DRM client instance
>> + */
>> +struct drm_client_dev {
>> +	struct list_head list;
>> +	struct drm_device *dev;
>> +	const struct drm_client_funcs *funcs;
>> +	struct mutex lock;
>> +	struct drm_file *file;
>> +	unsigned int file_ref_count;
>> +	u32 *crtcs;
>> +	unsigned int num_crtcs;
>> +	u32 min_width;
>> +	u32 max_width;
>> +	u32 min_height;
>> +	u32 max_height;
>> +	void *private;
>> +};
>> +
>> +void drm_client_free(struct drm_client_dev *client);
>> +int drm_client_register(const struct drm_client_funcs *funcs);
>> +void drm_client_unregister(const struct drm_client_funcs *funcs);
>> +
>> +void drm_client_dev_register(struct drm_device *dev);
>> +void drm_client_dev_unregister(struct drm_device *dev);
>> +void drm_client_dev_hotplug(struct drm_device *dev);
>> +void drm_client_dev_lastclose(struct drm_device *dev);
>> +
>> +int drm_client_get_file(struct drm_client_dev *client);
>> +void drm_client_put_file(struct drm_client_dev *client);
>> +struct drm_event *
>> +drm_client_read_event(struct drm_client_dev *client, bool block);
>> +
>> +struct drm_client_connector {
>> +	unsigned int conn_id;
>> +	unsigned int status;
>> +	unsigned int crtc_id;
>> +	struct drm_mode_modeinfo *modes;
>> +	unsigned int num_modes;
>> +	bool has_tile;
>> +	int tile_group;
>> +	u8 tile_h_loc, tile_v_loc;
>> +};
>> +
>> +struct drm_client_display {
>> +	struct drm_client_dev *client;
>> +
>> +	struct drm_client_connector **connectors;
>> +	unsigned int num_connectors;
>> +
>> +	struct mutex modes_lock;
>> +	struct drm_mode_modeinfo *modes;
>> +	unsigned int num_modes;
>> +
>> +	bool cloned;
>> +	bool no_flushing;
>> +};
>> +
>> +void drm_client_display_free(struct drm_client_display *display);
>> +struct drm_client_display *
>> +drm_client_display_get_first_enabled(struct drm_client_dev *client, bool strict);
>> +
>> +int drm_client_display_update_modes(struct drm_client_display *display,
>> +				    bool *mode_changed);
>> +
>> +static inline bool
>> +drm_client_display_is_tiled(struct drm_client_display *display)
>> +{
>> +	return !display->cloned && display->num_connectors > 1;
>> +}
>> +
>> +int drm_client_display_dpms(struct drm_client_display *display, int mode);
>> +int drm_client_display_wait_vblank(struct drm_client_display *display);
>> +
>> +struct drm_mode_modeinfo *
>> +drm_client_display_first_mode(struct drm_client_display *display);
>> +struct drm_mode_modeinfo *
>> +drm_client_display_next_mode(struct drm_client_display *display,
>> +			     struct drm_mode_modeinfo *mode);
>> +
>> +#define drm_client_display_for_each_mode(display, mode) \
>> +	for (mode = drm_client_display_first_mode(display); mode; \
>> +	     mode = drm_client_display_next_mode(display, mode))
>> +
>> +unsigned int
>> +drm_client_display_preferred_depth(struct drm_client_display *display);
>> +
>> +int drm_client_display_commit_mode(struct drm_client_display *display,
>> +				   u32 fb_id, struct drm_mode_modeinfo *mode);
>> +unsigned int drm_client_display_current_fb(struct drm_client_display *display);
>> +int drm_client_display_flush(struct drm_client_display *display, u32 fb_id,
>> +			     struct drm_clip_rect *clips, unsigned int num_clips);
>> +int drm_client_display_page_flip(struct drm_client_display *display, u32 fb_id,
>> +				 bool event);
>> +
>> +struct drm_client_buffer {
>> +	struct drm_client_dev *client;
>> +	u32 width;
>> +	u32 height;
>> +	u32 format;
>> +	u32 handle;
>> +	u32 pitch;
>> +	u64 size;
>> +	struct dma_buf *dma_buf;
>> +	void *vaddr;
>> +
>> +	unsigned int *fb_ids;
>> +	unsigned int num_fbs;
>> +};
>> +
>> +struct drm_client_buffer *
>> +drm_client_framebuffer_create(struct drm_client_dev *client,
>> +			      struct drm_mode_modeinfo *mode, u32 format);
>> +void drm_client_framebuffer_delete(struct drm_client_buffer *buffer);
>> +struct drm_client_buffer *
>> +drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height,
>> +			 u32 format);
>> +void drm_client_buffer_delete(struct drm_client_buffer *buffer);
>> +int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
>> +			    struct drm_mode_modeinfo *mode);
>> +int drm_client_buffer_rmfb(struct drm_client_buffer *buffer);
>> diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h
>> index 7c4fa32f3fc6..32dfed3d5a86 100644
>> --- a/include/drm/drm_device.h
>> +++ b/include/drm/drm_device.h
>> @@ -67,6 +67,7 @@ struct drm_device {
>>   
>>   	struct mutex filelist_mutex;
>>   	struct list_head filelist;
>> +	struct list_head filelist_internal;
>>   
>>   	/** \name Memory management */
>>   	/*@{ */
>> diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
>> index 5176c3797680..39af8a4be7b3 100644
>> --- a/include/drm/drm_file.h
>> +++ b/include/drm/drm_file.h
>> @@ -248,6 +248,13 @@ struct drm_file {
>>   	 */
>>   	void *driver_priv;
>>   
>> +	/**
>> +	 * @user_priv:
>> +	 *
>> +	 * Optional pointer for user private data. Useful for in-kernel clients.
>> +	 */
>> +	void *user_priv;
>> +
>>   	/**
>>   	 * @fbs:
>>   	 *
>> -- 
>> 2.15.1
>>

Daniel Vetter March 12, 2018, 4:51 p.m. UTC | #3

On Thu, Mar 08, 2018 at 06:12:11PM +0100, Noralf Tr??nnes wrote:
> 
> Den 06.03.2018 09.56, skrev Daniel Vetter:
> > On Thu, Feb 22, 2018 at 09:06:50PM +0100, Noralf Tr??nnes wrote:
> > > This adds an API for writing in-kernel clients.
> > > 
> > > TODO:
> > > - Flesh out and complete documentation.
> > > - Cloned displays is not tested.
> > > - Complete tiled display support and test it.
> > > - Test plug/unplug different monitors.
> > > - A runtime knob to prevent clients from attaching for debugging purposes.
> > > - Maybe a way to unbind individual client instances.
> > > - Maybe take the sysrq support in drm_fb_helper and move it here somehow.
> > > - Add suspend/resume callbacks.
> > >    Does anyone know why fbdev requires suspend/resume?
> > > 
> > > Signed-off-by: Noralf Tr??nnes <[e-mail]>
> > The core client api I like. Some of the opens I'm seeing:
> > 
> > - If we go with using the internal kms api directly instead of IOCTL
> >    wrappers then a huge pile of the functions you have here aren't needed
> >    (e.g. all the event stuff we can just directly use vblank events instead
> >    of all the wrapping). I'm leaning ever more into that direction, since
> >    much less code to add.
> 
> Looking at drm_fb_helper once again I now see an opportunity to simplify
> the modesetting code by nuking drm_fb_helper_connector and stop
> maintaining an array of connectors. It looks to be possible to just
> create an array temporarily in drm_setup_crtcs() for the duration of the
> function. The connectors we care about are ref counted and attached to
> modesets. This would remove the need for drm_fb_helper_add_one_connector().
> 
> So I might be able to do struct drm_fb_helper_crtc -> drm_client_crtc
> and let the client API take over drm_setup_crtcs(). I'll give it a try.

I'm more wondering why we need drm_client_crtc at all, why is drm_crtc not
good enough. Or maybe I'm missing something. Imo ioctl wrappers should be
the exception where we really, really need them (because the backend of
the ioctl isn't implemented in a generic way, e.g. dumb buffers), not for
stuff where we already have a perfectly useable in-kernel abi (anything
related to modesetting).

And in a way the ioctl wrappers wouldn't really be ioctl wrappers
conceptually, but simple share some of the same code with the ioctl call
chain. The idea is to provide some minimal wrappar around the ->dumb*
callbacks.

Anything else is not needed, I think.

> There is one challenge I see upfront and that's the i915 fb_helper
> callback in drm_setup_crtcs().
> 
> > - The register/unregister model needs more thought. Allowing both clients
> >    to register whenever they want to, and drm_device instances to come and
> >    go is what fbcon has done, and the resulting locking is a horror show.
> > 
> >    I think if we require that all in-kernel drm_clients are registers when
> >    loading drm.ko (and enabled/disabled only per module options and
> >    Kconfig), then we can throw out all the locking. That avoids a lot of
> >    the headaches.
> > 
> >    2nd, if the list of clients is static over the lifetime of drm.ko, we
> >    also don't need to iterate existing drivers. Which avoids me having to
> >    review the iterator patch (that's the other aspect where fbcon totally
> >    falls over and essentially just ignores a bunch of races).
> 
> Are you talking about linking the clients into drm.ko?
> 
> drivers/gpu/drm/Makefile:
> 
> drm-$(CONFIG_DRM_CLIENT_BOOTSPLASH) += client/drm_bootsplash.o
> 
> drivers/gpu/drm/drm_drv.c:
> 
> ??static int __init drm_core_init(void)
> ??{
> +?????? drm_bootsplash_register();
> +?????? drm_fbdev_register();
> ??}
> 
> drivers/gpu/drm/drm_internal.h:
> 
> #ifdef DRM_CLIENT_BOOTSPLASH
> void drm_bootsplash_register(void);
> #else
> static inline void drm_bootsplash_register(void)
> {
> }
> #endif
> 
> drivers/gpu/drm/client/drm_bootsplash.c:
> 
> static const struct drm_client_funcs drm_bootsplash_funcs = {
> ?????? .name?????? ?????? = "drm_bootsplash",
> ?????? .new?????? ?????? = drm_bootsplash_new,
> ?????? .remove?????? ?????? = drm_bootsplash_remove,
> ?????? .hotplug?????? = drm_bootsplash_hotplug,
> };
> 
> void drm_bootsplash_register(void)
> {
> ?????? drm_client_register(&drm_bootsplash_funcs);
> }
> 
> drivers/gpu/drm/drm_client.c:
> 
> static LIST_HEAD(drm_client_funcs_list);
> 
> void drm_client_register(const struct drm_client_funcs *funcs)
> {
> ?????? struct drm_client_funcs_entry *funcs_entry;
> 
> ?????? funcs_entry = kzalloc(sizeof(*funcs_entry), GFP_KERNEL);
> ?????? if (!funcs_entry) {
> ?????? ?????? DRM_ERROR("Failed to register: %s\n", funcs->name);
> ?????? ?????? return;
> ?????? }
> 
> ?????? funcs_entry->funcs = funcs;
> 
> ?????? list_add(&funcs_entry->list, &drm_client_funcs_list);
> 
> ?????? DRM_DEBUG_KMS("%s\n", funcs->name);
> }
> 
> 
> And each client having a runtime enable/disable knob:
> 
> drivers/gpu/drm/client/drm_bootsplash.c:
> 
> static bool drm_bootsplash_enabled = true;
> module_param_named(bootsplash_enabled, drm_bootsplash_enabled, bool, 0600);
> MODULE_PARM_DESC(bootsplash_enabled, "Enable bootsplash client
> [default=true]");


Yup, pretty much.

> Simple USB Display
> A few months back while looking at the udl shmem code, I got the idea
> that I could turn a Raspberry Pi Zero into a $5 USB to HDMI/DSI/DPI/DBI/TV
> adapter. The host side would be a simple tinydrm driver using the kernel
> compression lib to speed up transfers. The gadget/device side would be a
> userspace app decompressing the buffer into an exported dumb buffer.
> 
> While working with this client API I realized that I could use it and
> write a kernel gadget driver instead avoiding the challenge of going
> back and forth to userspace with the framebuffer. For such a client I
> would have preferred it to be a loadable module not linked into drm.ko
> to increase the chance that distributions would enable it.

I think that we can do as a loadable client, since you probably want some
configfs interface to define which drm driver it should control. The
reason behind the static list of built-in clients is purely for the
auto-register stuff that we want for fbdev emulation and other things.
Auto-registration where both sides can be loaded in any order is real pain
wrt locking. Explicit registration where you can load both sides is
totally fine and I think would cover your usb gadget display driver
use-case.

btw usb gadget driver to drive drm kms drivers sounds like a really cool
thing.
-Daniel

> 
> Noralf.
> 
> > > ---
> > >   drivers/gpu/drm/Kconfig             |    2 +
> > >   drivers/gpu/drm/Makefile            |    3 +-
> > >   drivers/gpu/drm/client/Kconfig      |    4 +
> > >   drivers/gpu/drm/client/Makefile     |    1 +
> > >   drivers/gpu/drm/client/drm_client.c | 1612 +++++++++++++++++++++++++++++++++++
> > I'd move this into main drm/ directory, it's fairly core stuff.
> > 
> > >   drivers/gpu/drm/drm_drv.c           |    6 +
> > >   drivers/gpu/drm/drm_file.c          |    3 +
> > >   drivers/gpu/drm/drm_probe_helper.c  |    3 +
> > >   include/drm/drm_client.h            |  192 +++++
> > >   include/drm/drm_device.h            |    1 +
> > >   include/drm/drm_file.h              |    7 +
> > >   11 files changed, 1833 insertions(+), 1 deletion(-)
> > >   create mode 100644 drivers/gpu/drm/client/Kconfig
> > >   create mode 100644 drivers/gpu/drm/client/Makefile
> > >   create mode 100644 drivers/gpu/drm/client/drm_client.c
> > >   create mode 100644 include/drm/drm_client.h
> > > 
> > > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> > > index deeefa7a1773..d4ae15f9ee9f 100644
> > > --- a/drivers/gpu/drm/Kconfig
> > > +++ b/drivers/gpu/drm/Kconfig
> > > @@ -154,6 +154,8 @@ config DRM_SCHED
> > >   	tristate
> > >   	depends on DRM
> > > +source "drivers/gpu/drm/client/Kconfig"
> > > +
> > >   source "drivers/gpu/drm/i2c/Kconfig"
> > >   source "drivers/gpu/drm/arm/Kconfig"
> > > diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> > > index 50093ff4479b..8e06dc7eeca1 100644
> > > --- a/drivers/gpu/drm/Makefile
> > > +++ b/drivers/gpu/drm/Makefile
> > > @@ -18,7 +18,7 @@ drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
> > >   		drm_encoder.o drm_mode_object.o drm_property.o \
> > >   		drm_plane.o drm_color_mgmt.o drm_print.o \
> > >   		drm_dumb_buffers.o drm_mode_config.o drm_vblank.o \
> > > -		drm_syncobj.o drm_lease.o
> > > +		drm_syncobj.o drm_lease.o client/drm_client.o
> > >   drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o
> > >   drm-$(CONFIG_DRM_VM) += drm_vm.o
> > > @@ -103,3 +103,4 @@ obj-$(CONFIG_DRM_MXSFB)	+= mxsfb/
> > >   obj-$(CONFIG_DRM_TINYDRM) += tinydrm/
> > >   obj-$(CONFIG_DRM_PL111) += pl111/
> > >   obj-$(CONFIG_DRM_TVE200) += tve200/
> > > +obj-y			+= client/
> > > diff --git a/drivers/gpu/drm/client/Kconfig b/drivers/gpu/drm/client/Kconfig
> > > new file mode 100644
> > > index 000000000000..4bb8e4655ff7
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/client/Kconfig
> > > @@ -0,0 +1,4 @@
> > > +menu "DRM Clients"
> > > +	depends on DRM
> > > +
> > > +endmenu
> > > diff --git a/drivers/gpu/drm/client/Makefile b/drivers/gpu/drm/client/Makefile
> > > new file mode 100644
> > > index 000000000000..f66554cd5c45
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/client/Makefile
> > > @@ -0,0 +1 @@
> > > +# SPDX-License-Identifier: GPL-2.0
> > > diff --git a/drivers/gpu/drm/client/drm_client.c b/drivers/gpu/drm/client/drm_client.c
> > > new file mode 100644
> > > index 000000000000..a633bf747316
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/client/drm_client.c
> > > @@ -0,0 +1,1612 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +// Copyright 2018 Noralf Tr??nnes
> > > +
> > > +#include <linux/dma-buf.h>
> > > +#include <linux/list.h>
> > > +#include <linux/mutex.h>
> > > +#include <linux/module.h>
> > > +#include <linux/slab.h>
> > > +
> > > +#include <drm/drm_client.h>
> > > +#include <drm/drm_connector.h>
> > > +#include <drm/drm_drv.h>
> > > +#include <drm/drm_file.h>
> > > +#include <drm/drm_ioctl.h>
> > > +#include <drm/drmP.h>
> > > +
> > > +#include "drm_crtc_internal.h"
> > > +#include "drm_internal.h"
> > > +
> > > +struct drm_client_funcs_entry {
> > > +	struct list_head list;
> > > +	const struct drm_client_funcs *funcs;
> > > +};
> > > +
> > > +static LIST_HEAD(drm_client_list);
> > I think the client list itself should be on the drm_device, not in one
> > global list that mixes up all the clients of all the drm_devices.
> > 
> > I'll skip reviewing details since we have a bunch of high-level questions
> > to figure out first.
> > -Daniel
> > 
> > > +static LIST_HEAD(drm_client_funcs_list);
> > > +static DEFINE_MUTEX(drm_client_list_lock);
> > > +
> > > +static void drm_client_new(struct drm_device *dev,
> > > +			   const struct drm_client_funcs *funcs)
> > > +{
> > > +	struct drm_client_dev *client;
> > > +	int ret;
> > > +
> > > +	lockdep_assert_held(&drm_client_list_lock);
> > > +
> > > +	client = kzalloc(sizeof(*client), GFP_KERNEL);
> > > +	if (!client)
> > > +		return;
> > > +
> > > +	mutex_init(&client->lock);
> > > +	client->dev = dev;
> > > +	client->funcs = funcs;
> > > +
> > > +	ret = funcs->new(client);
> > > +	DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n", funcs->name, ret);
> > > +	if (ret) {
> > > +		drm_client_free(client);
> > > +		return;
> > > +	}
> > > +
> > > +	list_add(&client->list, &drm_client_list);
> > > +}
> > > +
> > > +/**
> > > + * drm_client_free - Free DRM client resources
> > > + * @client: DRM client
> > > + *
> > > + * This is called automatically on client removal unless the client returns
> > > + * non-zero in the &drm_client_funcs->remove callback. The fbdev client does
> > > + * this when it can't close &drm_file because userspace has an open fd.
> > > + */
> > > +void drm_client_free(struct drm_client_dev *client)
> > > +{
> > > +	DRM_DEV_DEBUG_KMS(client->dev->dev, "%s\n", client->funcs->name);
> > > +	if (WARN_ON(client->file)) {
> > > +		client->file_ref_count = 1;
> > > +		drm_client_put_file(client);
> > > +	}
> > > +	mutex_destroy(&client->lock);
> > > +	kfree(client->crtcs);
> > > +	kfree(client);
> > > +}
> > > +EXPORT_SYMBOL(drm_client_free);
> > > +
> > > +static void drm_client_remove(struct drm_client_dev *client)
> > > +{
> > > +	lockdep_assert_held(&drm_client_list_lock);
> > > +
> > > +	list_del(&client->list);
> > > +
> > > +	if (!client->funcs->remove || !client->funcs->remove(client))
> > > +		drm_client_free(client);
> > > +}
> > > +
> > > +/**
> > > + * drm_client_register - Register a DRM client
> > > + * @funcs: Client callbacks
> > > + *
> > > + * Returns:
> > > + * Zero on success, negative error code on failure.
> > > + */
> > > +int drm_client_register(const struct drm_client_funcs *funcs)
> > > +{
> > > +	struct drm_client_funcs_entry *funcs_entry;
> > > +	struct drm_device_list_iter iter;
> > > +	struct drm_device *dev;
> > > +
> > > +	funcs_entry = kzalloc(sizeof(*funcs_entry), GFP_KERNEL);
> > > +	if (!funcs_entry)
> > > +		return -ENOMEM;
> > > +
> > > +	funcs_entry->funcs = funcs;
> > > +
> > > +	mutex_lock(&drm_global_mutex);
> > > +	mutex_lock(&drm_client_list_lock);
> > > +
> > > +	drm_device_list_iter_begin(&iter);
> > > +	drm_for_each_device_iter(dev, &iter)
> > > +		if (drm_core_check_feature(dev, DRIVER_MODESET))
> > > +			drm_client_new(dev, funcs);
> > > +	drm_device_list_iter_end(&iter);
> > > +
> > > +	list_add(&funcs_entry->list, &drm_client_funcs_list);
> > > +
> > > +	mutex_unlock(&drm_client_list_lock);
> > > +	mutex_unlock(&drm_global_mutex);
> > > +
> > > +	DRM_DEBUG_KMS("%s\n", funcs->name);
> > > +
> > > +	return 0;
> > > +}
> > > +EXPORT_SYMBOL(drm_client_register);
> > > +
> > > +/**
> > > + * drm_client_unregister - Unregister a DRM client
> > > + * @funcs: Client callbacks
> > > + */
> > > +void drm_client_unregister(const struct drm_client_funcs *funcs)
> > > +{
> > > +	struct drm_client_funcs_entry *funcs_entry;
> > > +	struct drm_client_dev *client, *tmp;
> > > +
> > > +	mutex_lock(&drm_client_list_lock);
> > > +
> > > +	list_for_each_entry_safe(client, tmp, &drm_client_list, list) {
> > > +		if (client->funcs == funcs)
> > > +			drm_client_remove(client);
> > > +	}
> > > +
> > > +	list_for_each_entry(funcs_entry, &drm_client_funcs_list, list) {
> > > +		if (funcs_entry->funcs == funcs) {
> > > +			list_del(&funcs_entry->list);
> > > +			kfree(funcs_entry);
> > > +			break;
> > > +		}
> > > +	}
> > > +
> > > +	mutex_unlock(&drm_client_list_lock);
> > > +
> > > +	DRM_DEBUG_KMS("%s\n", funcs->name);
> > > +}
> > > +EXPORT_SYMBOL(drm_client_unregister);
> > > +
> > > +void drm_client_dev_register(struct drm_device *dev)
> > > +{
> > > +	struct drm_client_funcs_entry *funcs_entry;
> > > +
> > > +	/*
> > > +	 * Minors are created at the beginning of drm_dev_register(), but can
> > > +	 * be removed again if the function fails. Since we iterate DRM devices
> > > +	 * by walking DRM minors, we need to stay under this lock.
> > > +	 */
> > > +	lockdep_assert_held(&drm_global_mutex);
> > > +
> > > +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
> > > +		return;
> > > +
> > > +	mutex_lock(&drm_client_list_lock);
> > > +	list_for_each_entry(funcs_entry, &drm_client_funcs_list, list)
> > > +		drm_client_new(dev, funcs_entry->funcs);
> > > +	mutex_unlock(&drm_client_list_lock);
> > > +}
> > > +
> > > +void drm_client_dev_unregister(struct drm_device *dev)
> > > +{
> > > +	struct drm_client_dev *client, *tmp;
> > > +
> > > +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
> > > +		return;
> > > +
> > > +	mutex_lock(&drm_client_list_lock);
> > > +	list_for_each_entry_safe(client, tmp, &drm_client_list, list)
> > > +		if (client->dev == dev)
> > > +			drm_client_remove(client);
> > > +	mutex_unlock(&drm_client_list_lock);
> > > +}
> > > +
> > > +void drm_client_dev_hotplug(struct drm_device *dev)
> > > +{
> > > +	struct drm_client_dev *client;
> > > +	int ret;
> > > +
> > > +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
> > > +		return;
> > > +
> > > +	mutex_lock(&drm_client_list_lock);
> > > +	list_for_each_entry(client, &drm_client_list, list)
> > > +		if (client->dev == dev && client->funcs->hotplug) {
> > > +			ret = client->funcs->hotplug(client);
> > > +			DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n",
> > > +					  client->funcs->name, ret);
> > > +		}
> > > +	mutex_unlock(&drm_client_list_lock);
> > > +}
> > > +
> > > +void drm_client_dev_lastclose(struct drm_device *dev)
> > > +{
> > > +	struct drm_client_dev *client;
> > > +	int ret;
> > > +
> > > +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
> > > +		return;
> > > +
> > > +	mutex_lock(&drm_client_list_lock);
> > > +	list_for_each_entry(client, &drm_client_list, list)
> > > +		if (client->dev == dev && client->funcs->lastclose) {
> > > +			ret = client->funcs->lastclose(client);
> > > +			DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n",
> > > +					  client->funcs->name, ret);
> > > +		}
> > > +	mutex_unlock(&drm_client_list_lock);
> > > +}
> > > +
> > > +/* Get static info */
> > > +static int drm_client_init(struct drm_client_dev *client, struct drm_file *file)
> > > +{
> > > +	struct drm_mode_card_res card_res = {};
> > > +	struct drm_device *dev = client->dev;
> > > +	u32 *crtcs;
> > > +	int ret;
> > > +
> > > +	ret = drm_mode_getresources(dev, &card_res, file, false);
> > > +	if (ret)
> > > +		return ret;
> > > +	if (!card_res.count_crtcs)
> > > +		return -ENOENT;
> > > +
> > > +	crtcs = kmalloc_array(card_res.count_crtcs, sizeof(*crtcs), GFP_KERNEL);
> > > +	if (!crtcs)
> > > +		return -ENOMEM;
> > > +
> > > +	card_res.count_fbs = 0;
> > > +	card_res.count_connectors = 0;
> > > +	card_res.count_encoders = 0;
> > > +	card_res.crtc_id_ptr = (unsigned long)crtcs;
> > > +
> > > +	ret = drm_mode_getresources(dev, &card_res, file, false);
> > > +	if (ret) {
> > > +		kfree(crtcs);
> > > +		return ret;
> > > +	}
> > > +
> > > +	client->crtcs = crtcs;
> > > +	client->num_crtcs = card_res.count_crtcs;
> > > +	client->min_width = card_res.min_width;
> > > +	client->max_width = card_res.max_width;
> > > +	client->min_height = card_res.min_height;
> > > +	client->max_height = card_res.max_height;
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +/**
> > > + * drm_client_get_file - Get a DRM file
> > > + * @client: DRM client
> > > + *
> > > + * This function makes sure the client has a &drm_file available. The client
> > > + * doesn't normally need to call this, since all client functions that depends
> > > + * on a DRM file will call it. A matching call to drm_client_put_file() is
> > > + * necessary.
> > > + *
> > > + * The reason for not opening a DRM file when a @client is created is because
> > > + * we have to take a ref on the driver module due to &drm_driver->postclose
> > > + * being called in drm_file_free(). Having a DRM file open for the lifetime of
> > > + * the client instance would block driver module unload.
> > > + *
> > > + * Returns:
> > > + * Zero on success, negative error code on failure.
> > > + */
> > > +int drm_client_get_file(struct drm_client_dev *client)
> > > +{
> > > +	struct drm_device *dev = client->dev;
> > > +	struct drm_file *file;
> > > +	int ret = 0;
> > > +
> > > +	mutex_lock(&client->lock);
> > > +
> > > +	if (client->file_ref_count++) {
> > > +		mutex_unlock(&client->lock);
> > > +		return 0;
> > > +	}
> > > +
> > > +	if (!try_module_get(dev->driver->fops->owner)) {
> > > +		ret = -ENODEV;
> > > +		goto err_unlock;
> > > +	}
> > > +
> > > +	drm_dev_get(dev);
> > > +
> > > +	file = drm_file_alloc(dev->primary);
> > > +	if (IS_ERR(file)) {
> > > +		ret = PTR_ERR(file);
> > > +		goto err_put;
> > > +	}
> > > +
> > > +	if (!client->crtcs) {
> > > +		ret = drm_client_init(client, file);
> > > +		if (ret)
> > > +			goto err_free;
> > > +	}
> > > +
> > > +	mutex_lock(&dev->filelist_mutex);
> > > +	list_add(&file->lhead, &dev->filelist_internal);
> > > +	mutex_unlock(&dev->filelist_mutex);
> > > +
> > > +	client->file = file;
> > > +
> > > +	mutex_unlock(&client->lock);
> > > +
> > > +	return 0;
> > > +
> > > +err_free:
> > > +	drm_file_free(file);
> > > +err_put:
> > > +	drm_dev_put(dev);
> > > +	module_put(dev->driver->fops->owner);
> > > +err_unlock:
> > > +	client->file_ref_count = 0;
> > > +	mutex_unlock(&client->lock);
> > > +
> > > +	return ret;
> > > +}
> > > +EXPORT_SYMBOL(drm_client_get_file);
> > > +
> > > +void drm_client_put_file(struct drm_client_dev *client)
> > > +{
> > > +	struct drm_device *dev = client->dev;
> > > +
> > > +	if (!client)
> > > +		return;
> > > +
> > > +	mutex_lock(&client->lock);
> > > +
> > > +	if (WARN_ON(!client->file_ref_count))
> > > +		goto out_unlock;
> > > +
> > > +	if (--client->file_ref_count)
> > > +		goto out_unlock;
> > > +
> > > +	mutex_lock(&dev->filelist_mutex);
> > > +	list_del(&client->file->lhead);
> > > +	mutex_unlock(&dev->filelist_mutex);
> > > +
> > > +	drm_file_free(client->file);
> > > +	client->file = NULL;
> > > +	drm_dev_put(dev);
> > > +	module_put(dev->driver->fops->owner);
> > > +out_unlock:
> > > +	mutex_unlock(&client->lock);
> > > +}
> > > +EXPORT_SYMBOL(drm_client_put_file);
> > > +
> > > +static struct drm_pending_event *
> > > +drm_client_read_get_pending_event(struct drm_device *dev, struct drm_file *file)
> > > +{
> > > +	struct drm_pending_event *e = NULL;
> > > +	int ret;
> > > +
> > > +	ret = mutex_lock_interruptible(&file->event_read_lock);
> > > +	if (ret)
> > > +		return ERR_PTR(ret);
> > > +
> > > +	spin_lock_irq(&dev->event_lock);
> > > +	if (!list_empty(&file->event_list)) {
> > > +		e = list_first_entry(&file->event_list,
> > > +				     struct drm_pending_event, link);
> > > +		file->event_space += e->event->length;
> > > +		list_del(&e->link);
> > > +	}
> > > +	spin_unlock_irq(&dev->event_lock);
> > > +
> > > +	mutex_unlock(&file->event_read_lock);
> > > +
> > > +	return e;
> > > +}
> > > +
> > > +struct drm_event *
> > > +drm_client_read_event(struct drm_client_dev *client, bool block)
> > > +{
> > > +	struct drm_file *file = client->file;
> > > +	struct drm_device *dev = client->dev;
> > > +	struct drm_pending_event *e;
> > > +	struct drm_event *event;
> > > +	int ret;
> > > +
> > > +	/* Allocate so it fits all events, there's a sanity check later */
> > > +	event = kzalloc(128, GFP_KERNEL);
> > > +	if (!event)
> > > +		return ERR_PTR(-ENOMEM);
> > > +
> > > +	e = drm_client_read_get_pending_event(dev, file);
> > > +	if (IS_ERR(e)) {
> > > +		ret = PTR_ERR(e);
> > > +		goto err_free;
> > > +	}
> > > +
> > > +	if (!e && !block) {
> > > +		ret = 0;
> > > +		goto err_free;
> > > +	}
> > > +
> > > +	ret = wait_event_interruptible_timeout(file->event_wait,
> > > +					       !list_empty(&file->event_list),
> > > +					       5 * HZ);
> > > +	if (!ret)
> > > +		ret = -ETIMEDOUT;
> > > +	if (ret < 0)
> > > +		goto err_free;
> > > +
> > > +	e = drm_client_read_get_pending_event(dev, file);
> > > +	if (IS_ERR_OR_NULL(e)) {
> > > +		ret = PTR_ERR_OR_ZERO(e);
> > > +		goto err_free;
> > > +	}
> > > +
> > > +	if (WARN_ON(e->event->length > 128)) {
> > > +		/* Increase buffer if this happens */
> > > +		ret = -ENOMEM;
> > > +		goto err_free;
> > > +	}
> > > +
> > > +	memcpy(event, e->event, e->event->length);
> > > +	kfree(e);
> > > +
> > > +	return event;
> > > +
> > > +err_free:
> > > +	kfree(event);
> > > +
> > > +	return ret ? ERR_PTR(ret) : NULL;
> > > +}
> > > +EXPORT_SYMBOL(drm_client_read_event);
> > > +
> > > +static void drm_client_connector_free(struct drm_client_connector *connector)
> > > +{
> > > +	if (!connector)
> > > +		return;
> > > +	kfree(connector->modes);
> > > +	kfree(connector);
> > > +}
> > > +
> > > +static struct drm_client_connector *
> > > +drm_client_get_connector(struct drm_client_dev *client, unsigned int id)
> > > +{
> > > +	struct drm_mode_get_connector req = {
> > > +		.connector_id = id,
> > > +	};
> > > +	struct drm_client_connector *connector;
> > > +	struct drm_mode_modeinfo *modes = NULL;
> > > +	struct drm_device *dev = client->dev;
> > > +	struct drm_connector *conn;
> > > +	bool non_desktop;
> > > +	int ret;
> > > +
> > > +	connector = kzalloc(sizeof(*connector), GFP_KERNEL);
> > > +	if (!connector)
> > > +		return ERR_PTR(-ENOMEM);
> > > +
> > > +	ret = drm_mode_getconnector(dev, &req, client->file, false);
> > > +	if (ret)
> > > +		goto err_free;
> > > +
> > > +	connector->conn_id = id;
> > > +	connector->status = req.connection;
> > > +
> > > +	conn = drm_connector_lookup(dev, client->file, id);
> > > +	if (!conn) {
> > > +		ret = -ENOENT;
> > > +		goto err_free;
> > > +	}
> > > +
> > > +	non_desktop = conn->display_info.non_desktop;
> > > +
> > > +	connector->has_tile = conn->has_tile;
> > > +	connector->tile_h_loc = conn->tile_h_loc;
> > > +	connector->tile_v_loc = conn->tile_v_loc;
> > > +	if (conn->tile_group)
> > > +		connector->tile_group = conn->tile_group->id;
> > > +
> > > +	drm_connector_put(conn);
> > > +
> > > +	if (non_desktop) {
> > > +		kfree(connector);
> > > +		return NULL;
> > > +	}
> > > +
> > > +	if (!req.count_modes)
> > > +		return connector;
> > > +
> > > +	modes = kcalloc(req.count_modes, sizeof(*modes), GFP_KERNEL);
> > > +	if (!modes) {
> > > +		ret = -ENOMEM;
> > > +		goto err_free;
> > > +	}
> > > +
> > > +	connector->modes = modes;
> > > +	connector->num_modes = req.count_modes;
> > > +
> > > +	req.count_props = 0;
> > > +	req.count_encoders = 0;
> > > +	req.modes_ptr = (unsigned long)modes;
> > > +
> > > +	ret = drm_mode_getconnector(dev, &req, client->file, false);
> > > +	if (ret)
> > > +		goto err_free;
> > > +
> > > +	return connector;
> > > +
> > > +err_free:
> > > +	kfree(modes);
> > > +	kfree(connector);
> > > +
> > > +	return ERR_PTR(ret);
> > > +}
> > > +
> > > +static int drm_client_get_connectors(struct drm_client_dev *client,
> > > +				     struct drm_client_connector ***connectors)
> > > +{
> > > +	struct drm_mode_card_res card_res = {};
> > > +	struct drm_device *dev = client->dev;
> > > +	int ret, num_connectors;
> > > +	u32 *connector_ids;
> > > +	unsigned int i;
> > > +
> > > +	ret = drm_mode_getresources(dev, &card_res, client->file, false);
> > > +	if (ret)
> > > +		return ret;
> > > +	if (!card_res.count_connectors)
> > > +		return 0;
> > > +
> > > +	num_connectors = card_res.count_connectors;
> > > +	connector_ids = kcalloc(num_connectors,
> > > +				sizeof(*connector_ids), GFP_KERNEL);
> > > +	if (!connector_ids)
> > > +		return -ENOMEM;
> > > +
> > > +	card_res.count_fbs = 0;
> > > +	card_res.count_crtcs = 0;
> > > +	card_res.count_encoders = 0;
> > > +	card_res.connector_id_ptr = (unsigned long)connector_ids;
> > > +
> > > +	ret = drm_mode_getresources(dev, &card_res, client->file, false);
> > > +	if (ret)
> > > +		goto err_free;
> > > +
> > > +	*connectors = kcalloc(num_connectors, sizeof(**connectors), GFP_KERNEL);
> > > +	if (!(*connectors)) {
> > > +		ret = -ENOMEM;
> > > +		goto err_free;
> > > +	}
> > > +
> > > +	for (i = 0; i < num_connectors; i++) {
> > > +		struct drm_client_connector *connector;
> > > +
> > > +		connector = drm_client_get_connector(client, connector_ids[i]);
> > > +		if (IS_ERR(connector)) {
> > > +			ret = PTR_ERR(connector);
> > > +			goto err_free;
> > > +		}
> > > +		if (connector)
> > > +			(*connectors)[i] = connector;
> > > +		else
> > > +			num_connectors--;
> > > +	}
> > > +
> > > +	if (!num_connectors) {
> > > +		ret = 0;
> > > +		goto err_free;
> > > +	}
> > > +
> > > +	return num_connectors;
> > > +
> > > +err_free:
> > > +	if (connectors)
> > > +		for (i = 0; i < num_connectors; i++)
> > > +			drm_client_connector_free((*connectors)[i]);
> > > +
> > > +	kfree(connectors);
> > > +	kfree(connector_ids);
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static bool
> > > +drm_client_connector_is_enabled(struct drm_client_connector *connector,
> > > +				bool strict)
> > > +{
> > > +	if (strict)
> > > +		return connector->status == connector_status_connected;
> > > +	else
> > > +		return connector->status != connector_status_disconnected;
> > > +}
> > > +
> > > +struct drm_mode_modeinfo *
> > > +drm_client_display_first_mode(struct drm_client_display *display)
> > > +{
> > > +	if (!display->num_modes)
> > > +		return NULL;
> > > +	return display->modes;
> > > +}
> > > +EXPORT_SYMBOL(drm_client_display_first_mode);
> > > +
> > > +struct drm_mode_modeinfo *
> > > +drm_client_display_next_mode(struct drm_client_display *display,
> > > +			     struct drm_mode_modeinfo *mode)
> > > +{
> > > +	struct drm_mode_modeinfo *modes = display->modes;
> > > +
> > > +	if (++mode < &modes[display->num_modes])
> > > +		return mode;
> > > +
> > > +	return NULL;
> > > +}
> > > +EXPORT_SYMBOL(drm_client_display_next_mode);
> > > +
> > > +static void
> > > +drm_client_display_fill_tile_modes(struct drm_client_display *display,
> > > +				   struct drm_mode_modeinfo *tile_modes)
> > > +{
> > > +	unsigned int i, j, num_modes = display->connectors[0]->num_modes;
> > > +	struct drm_mode_modeinfo *tile_mode, *conn_mode;
> > > +
> > > +	if (!num_modes) {
> > > +		kfree(tile_modes);
> > > +		kfree(display->modes);
> > > +		display->modes = NULL;
> > > +		display->num_modes = 0;
> > > +		return;
> > > +	}
> > > +
> > > +	for (i = 0; i < num_modes; i++) {
> > > +		tile_mode = &tile_modes[i];
> > > +
> > > +		conn_mode = &display->connectors[0]->modes[i];
> > > +		tile_mode->clock = conn_mode->clock;
> > > +		tile_mode->vscan = conn_mode->vscan;
> > > +		tile_mode->vrefresh = conn_mode->vrefresh;
> > > +		tile_mode->flags = conn_mode->flags;
> > > +		tile_mode->type = conn_mode->type;
> > > +
> > > +		for (j = 0; j < display->num_connectors; j++) {
> > > +			conn_mode = &display->connectors[j]->modes[i];
> > > +
> > > +			if (!display->connectors[j]->tile_h_loc) {
> > > +				tile_mode->hdisplay += conn_mode->hdisplay;
> > > +				tile_mode->hsync_start += conn_mode->hsync_start;
> > > +				tile_mode->hsync_end += conn_mode->hsync_end;
> > > +				tile_mode->htotal += conn_mode->htotal;
> > > +			}
> > > +
> > > +			if (!display->connectors[j]->tile_v_loc) {
> > > +				tile_mode->vdisplay += conn_mode->vdisplay;
> > > +				tile_mode->vsync_start += conn_mode->vsync_start;
> > > +				tile_mode->vsync_end += conn_mode->vsync_end;
> > > +				tile_mode->vtotal += conn_mode->vtotal;
> > > +			}
> > > +		}
> > > +	}
> > > +
> > > +	kfree(display->modes);
> > > +	display->modes = tile_modes;
> > > +	display->num_modes = num_modes;
> > > +}
> > > +
> > > +/**
> > > + * drm_client_display_update_modes - Fetch display modes
> > > + * @display: Client display
> > > + * @mode_changed: Optional pointer to boolen which return whether the modes
> > > + *                have changed or not.
> > > + *
> > > + * This function can be used in the client hotplug callback to check if the
> > > + * video modes have changed and get them up-to-date.
> > > + *
> > > + * Returns:
> > > + * Number of modes on success, negative error code on failure.
> > > + */
> > > +int drm_client_display_update_modes(struct drm_client_display *display,
> > > +				    bool *mode_changed)
> > > +{
> > > +	unsigned int num_connectors = display->num_connectors;
> > > +	struct drm_client_dev *client = display->client;
> > > +	struct drm_mode_modeinfo *display_tile_modes;
> > > +	struct drm_client_connector **connectors;
> > > +	unsigned int i, num_modes = 0;
> > > +	bool dummy_changed = false;
> > > +	int ret;
> > > +
> > > +	if (mode_changed)
> > > +		*mode_changed = false;
> > > +	else
> > > +		mode_changed = &dummy_changed;
> > > +
> > > +	if (display->cloned)
> > > +		return 2;
> > > +
> > > +	ret = drm_client_get_file(client);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	connectors = kcalloc(num_connectors, sizeof(*connectors), GFP_KERNEL);
> > > +	if (!connectors) {
> > > +		ret = -ENOMEM;
> > > +		goto out_put_file;
> > > +	}
> > > +
> > > +	/* Get a new set for comparison */
> > > +	for (i = 0; i < num_connectors; i++) {
> > > +		connectors[i] = drm_client_get_connector(client, display->connectors[i]->conn_id);
> > > +		if (IS_ERR_OR_NULL(connectors[i])) {
> > > +			ret = PTR_ERR_OR_ZERO(connectors[i]);
> > > +			if (!ret)
> > > +				ret = -ENOENT;
> > > +			goto out_cleanup;
> > > +		}
> > > +	}
> > > +
> > > +	/* All connectors should have the same number of modes */
> > > +	num_modes = connectors[0]->num_modes;
> > > +	for (i = 0; i < num_connectors; i++) {
> > > +		if (num_modes != connectors[i]->num_modes) {
> > > +			ret = -EINVAL;
> > > +			goto out_cleanup;
> > > +		}
> > > +	}
> > > +
> > > +	if (num_connectors > 1) {
> > > +		display_tile_modes = kcalloc(num_modes, sizeof(*display_tile_modes), GFP_KERNEL);
> > > +		if (!display_tile_modes) {
> > > +			ret = -ENOMEM;
> > > +			goto out_cleanup;
> > > +		}
> > > +	}
> > > +
> > > +	mutex_lock(&display->modes_lock);
> > > +
> > > +	for (i = 0; i < num_connectors; i++) {
> > > +		display->connectors[i]->status = connectors[i]->status;
> > > +		if (display->connectors[i]->num_modes != connectors[i]->num_modes) {
> > > +			display->connectors[i]->num_modes = connectors[i]->num_modes;
> > > +			kfree(display->connectors[i]->modes);
> > > +			display->connectors[i]->modes = connectors[i]->modes;
> > > +			connectors[i]->modes = NULL;
> > > +			*mode_changed = true;
> > > +		}
> > > +	}
> > > +
> > > +	if (num_connectors > 1)
> > > +		drm_client_display_fill_tile_modes(display, display_tile_modes);
> > > +	else
> > > +		display->modes = display->connectors[0]->modes;
> > > +
> > > +	mutex_unlock(&display->modes_lock);
> > > +
> > > +out_cleanup:
> > > +	for (i = 0; i < num_connectors; i++)
> > > +		drm_client_connector_free(connectors[i]);
> > > +	kfree(connectors);
> > > +out_put_file:
> > > +	drm_client_put_file(client);
> > > +
> > > +	return ret ? ret : num_modes;
> > > +}
> > > +EXPORT_SYMBOL(drm_client_display_update_modes);
> > > +
> > > +void drm_client_display_free(struct drm_client_display *display)
> > > +{
> > > +	unsigned int i;
> > > +
> > > +	if (!display)
> > > +		return;
> > > +
> > > +	/* tile modes? */
> > > +	if (display->modes != display->connectors[0]->modes)
> > > +		kfree(display->modes);
> > > +
> > > +	for (i = 0; i < display->num_connectors; i++)
> > > +		drm_client_connector_free(display->connectors[i]);
> > > +
> > > +	kfree(display->connectors);
> > > +	mutex_destroy(&display->modes_lock);
> > > +	kfree(display);
> > > +}
> > > +EXPORT_SYMBOL(drm_client_display_free);
> > > +
> > > +static struct drm_client_display *
> > > +drm_client_display_alloc(struct drm_client_dev *client,
> > > +			 unsigned int num_connectors)
> > > +{
> > > +	struct drm_client_display *display;
> > > +	struct drm_client_connector **connectors;
> > > +
> > > +	display = kzalloc(sizeof(*display), GFP_KERNEL);
> > > +	connectors = kcalloc(num_connectors, sizeof(*connectors), GFP_KERNEL);
> > > +	if (!display || !connectors) {
> > > +		kfree(display);
> > > +		kfree(connectors);
> > > +		return NULL;
> > > +	}
> > > +
> > > +	mutex_init(&display->modes_lock);
> > > +	display->client = client;
> > > +	display->connectors = connectors;
> > > +	display->num_connectors = num_connectors;
> > > +
> > > +	return display;
> > > +}
> > > +
> > > +/* Logic is from drm_fb_helper */
> > > +static struct drm_client_display *
> > > +drm_client_connector_pick_cloned(struct drm_client_dev *client,
> > > +				 struct drm_client_connector **connectors,
> > > +				 unsigned int num_connectors)
> > > +{
> > > +	struct drm_mode_modeinfo modes[2], udmt_mode, *mode, *tmp;
> > > +	struct drm_display_mode *dmt_display_mode = NULL;
> > > +	unsigned int i, j, conns[2], num_conns = 0;
> > > +	struct drm_client_connector *connector;
> > > +	struct drm_device *dev = client->dev;
> > > +	struct drm_client_display *display;
> > > +
> > > +	/* only contemplate cloning in the single crtc case */
> > > +	if (dev->mode_config.num_crtc > 1)
> > > +		return NULL;
> > > +retry:
> > > +	for (i = 0; i < num_connectors; i++) {
> > > +		connector = connectors[i];
> > > +		if (!connector || connector->has_tile || !connector->num_modes)
> > > +			continue;
> > > +
> > > +		for (j = 0; j < connector->num_modes; j++) {
> > > +			mode = &connector->modes[j];
> > > +			if (dmt_display_mode) {
> > > +				if (drm_umode_equal(&udmt_mode, mode)) {
> > > +					conns[num_conns] = i;
> > > +					modes[num_conns++] = *mode;
> > > +					break;
> > > +				}
> > > +			} else {
> > > +				if (mode->type & DRM_MODE_TYPE_USERDEF) {
> > > +					conns[num_conns] = i;
> > > +					modes[num_conns++] = *mode;
> > > +					break;
> > > +				}
> > > +			}
> > > +		}
> > > +		if (num_conns == 2)
> > > +			break;
> > > +	}
> > > +
> > > +	if (num_conns == 2)
> > > +		goto found;
> > > +
> > > +	if (dmt_display_mode)
> > > +		return NULL;
> > > +
> > > +	dmt_display_mode = drm_mode_find_dmt(dev, 1024, 768, 60, false);
> > > +	drm_mode_convert_to_umode(&udmt_mode, dmt_display_mode);
> > > +	drm_mode_destroy(dev, dmt_display_mode);
> > > +
> > > +	goto retry;
> > > +
> > > +found:
> > > +	tmp = kcalloc(2, sizeof(*tmp), GFP_KERNEL);
> > > +	if (!tmp)
> > > +		return ERR_PTR(-ENOMEM);
> > > +
> > > +	display = drm_client_display_alloc(client, 2);
> > > +	if (!display) {
> > > +		kfree(tmp);
> > > +		return ERR_PTR(-ENOMEM);
> > > +	}
> > > +
> > > +	for (i = 0; i < 2; i++) {
> > > +		connector = connectors[conns[i]];
> > > +		display->connectors[i] = connector;
> > > +		connectors[conns[i]] = NULL;
> > > +		kfree(connector->modes);
> > > +		tmp[i] = modes[i];
> > > +		connector->modes = &tmp[i];
> > > +		connector->num_modes = 1;
> > > +	}
> > > +
> > > +	display->cloned = true;
> > > +	display->modes = &tmp[0];
> > > +	display->num_modes = 1;
> > > +
> > > +	return display;
> > > +}
> > > +
> > > +static struct drm_client_display *
> > > +drm_client_connector_pick_tile(struct drm_client_dev *client,
> > > +			       struct drm_client_connector **connectors,
> > > +			       unsigned int num_connectors)
> > > +{
> > > +	unsigned int i, num_conns, num_modes, tile_group = 0;
> > > +	struct drm_mode_modeinfo *tile_modes = NULL;
> > > +	struct drm_client_connector *connector;
> > > +	struct drm_client_display *display;
> > > +	u16 conns[32];
> > > +
> > > +	for (i = 0; i < num_connectors; i++) {
> > > +		connector = connectors[i];
> > > +		if (!connector || !connector->tile_group)
> > > +			continue;
> > > +
> > > +		if (!tile_group) {
> > > +			tile_group = connector->tile_group;
> > > +			num_modes = connector->num_modes;
> > > +		}
> > > +
> > > +		if (connector->tile_group != tile_group)
> > > +			continue;
> > > +
> > > +		if (num_modes != connector->num_modes) {
> > > +			DRM_ERROR("Tile connectors must have the same number of modes\n");
> > > +			return ERR_PTR(-EINVAL);
> > > +		}
> > > +
> > > +		conns[num_conns++] = i;
> > > +		if (WARN_ON(num_conns == 33))
> > > +			return ERR_PTR(-EINVAL);
> > > +	}
> > > +
> > > +	if (!num_conns)
> > > +		return NULL;
> > > +
> > > +	if (num_modes) {
> > > +		tile_modes = kcalloc(num_modes, sizeof(*tile_modes), GFP_KERNEL);
> > > +		if (!tile_modes)
> > > +			return ERR_PTR(-ENOMEM);
> > > +	}
> > > +
> > > +	display = drm_client_display_alloc(client, num_conns);
> > > +	if (!display) {
> > > +		kfree(tile_modes);
> > > +		return ERR_PTR(-ENOMEM);
> > > +	}
> > > +
> > > +	if (num_modes)
> > > +		drm_client_display_fill_tile_modes(display, tile_modes);
> > > +
> > > +	return display;
> > > +}
> > > +
> > > +static struct drm_client_display *
> > > +drm_client_connector_pick_not_tile(struct drm_client_dev *client,
> > > +				   struct drm_client_connector **connectors,
> > > +				   unsigned int num_connectors)
> > > +{
> > > +	struct drm_client_display *display;
> > > +	unsigned int i;
> > > +
> > > +	for (i = 0; i < num_connectors; i++) {
> > > +		if (!connectors[i] || connectors[i]->has_tile)
> > > +			continue;
> > > +		break;
> > > +	}
> > > +
> > > +	if (i == num_connectors)
> > > +		return NULL;
> > > +
> > > +	display = drm_client_display_alloc(client, 1);
> > > +	if (!display)
> > > +		return ERR_PTR(-ENOMEM);
> > > +
> > > +	display->connectors[0] = connectors[i];
> > > +	connectors[i] = NULL;
> > > +	display->modes = display->connectors[0]->modes;
> > > +	display->num_modes = display->connectors[0]->num_modes;
> > > +
> > > +	return display;
> > > +}
> > > +
> > > +/* Get connectors and bundle them up into displays */
> > > +static int drm_client_get_displays(struct drm_client_dev *client,
> > > +				   struct drm_client_display ***displays)
> > > +{
> > > +	int ret, num_connectors, num_displays = 0;
> > > +	struct drm_client_connector **connectors;
> > > +	struct drm_client_display *display;
> > > +	unsigned int i;
> > > +
> > > +	ret = drm_client_get_file(client);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	num_connectors = drm_client_get_connectors(client, &connectors);
> > > +	if (num_connectors <= 0) {
> > > +		ret = num_connectors;
> > > +		goto err_put_file;
> > > +	}
> > > +
> > > +	*displays = kcalloc(num_connectors, sizeof(*displays), GFP_KERNEL);
> > > +	if (!(*displays)) {
> > > +		ret = -ENOMEM;
> > > +		goto err_free;
> > > +	}
> > > +
> > > +	display = drm_client_connector_pick_cloned(client, connectors,
> > > +						   num_connectors);
> > > +	if (IS_ERR(display)) {
> > > +		ret = PTR_ERR(display);
> > > +		goto err_free;
> > > +	}
> > > +	if (display)
> > > +		(*displays)[num_displays++] = display;
> > > +
> > > +	for (i = 0; i < num_connectors; i++) {
> > > +		display = drm_client_connector_pick_tile(client, connectors,
> > > +							 num_connectors);
> > > +		if (IS_ERR(display)) {
> > > +			ret = PTR_ERR(display);
> > > +			goto err_free;
> > > +		}
> > > +		if (!display)
> > > +			break;
> > > +		(*displays)[num_displays++] = display;
> > > +	}
> > > +
> > > +	for (i = 0; i < num_connectors; i++) {
> > > +		display = drm_client_connector_pick_not_tile(client, connectors,
> > > +							     num_connectors);
> > > +		if (IS_ERR(display)) {
> > > +			ret = PTR_ERR(display);
> > > +			goto err_free;
> > > +		}
> > > +		if (!display)
> > > +			break;
> > > +		(*displays)[num_displays++] = display;
> > > +	}
> > > +
> > > +	for (i = 0; i < num_connectors; i++) {
> > > +		if (connectors[i]) {
> > > +			DRM_INFO("Connector %u fell through the cracks.\n",
> > > +				 connectors[i]->conn_id);
> > > +			drm_client_connector_free(connectors[i]);
> > > +		}
> > > +	}
> > > +
> > > +	drm_client_put_file(client);
> > > +	kfree(connectors);
> > > +
> > > +	return num_displays;
> > > +
> > > +err_free:
> > > +	for (i = 0; i < num_displays; i++)
> > > +		drm_client_display_free((*displays)[i]);
> > > +	kfree(*displays);
> > > +	*displays = NULL;
> > > +	for (i = 0; i < num_connectors; i++)
> > > +		drm_client_connector_free(connectors[i]);
> > > +	kfree(connectors);
> > > +err_put_file:
> > > +	drm_client_put_file(client);
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static bool
> > > +drm_client_display_is_enabled(struct drm_client_display *display, bool strict)
> > > +{
> > > +	unsigned int i;
> > > +
> > > +	if (!display->num_modes)
> > > +		return false;
> > > +
> > > +	for (i = 0; i < display->num_connectors; i++)
> > > +		if (!drm_client_connector_is_enabled(display->connectors[i], strict))
> > > +			return false;
> > > +
> > > +	return true;
> > > +}
> > > +
> > > +/**
> > > + * drm_client_display_get_first_enabled - Get first enabled display
> > > + * @client: DRM client
> > > + * @strict: If true the connector(s) have to be connected, if false they can
> > > + *          also have unknown status.
> > > + *
> > > + * This function gets all connectors and bundles them into displays
> > > + * (tiled/cloned). It then picks the first one with connectors that is enabled
> > > + * according to @strict.
> > > + *
> > > + * Returns:
> > > + * Pointer to a client display if such a display was found, NULL if not found
> > > + * or an error pointer on failure.
> > > + */
> > > +struct drm_client_display *
> > > +drm_client_display_get_first_enabled(struct drm_client_dev *client, bool strict)
> > > +{
> > > +	struct drm_client_display **displays, *display = NULL;
> > > +	int num_displays;
> > > +	unsigned int i;
> > > +
> > > +	num_displays = drm_client_get_displays(client, &displays);
> > > +	if (num_displays < 0)
> > > +		return ERR_PTR(num_displays);
> > > +	if (!num_displays)
> > > +		return NULL;
> > > +
> > > +	for (i = 0; i < num_displays; i++) {
> > > +		if (!display &&
> > > +		    drm_client_display_is_enabled(displays[i], strict)) {
> > > +			display = displays[i];
> > > +			continue;
> > > +		}
> > > +		drm_client_display_free(displays[i]);
> > > +	}
> > > +
> > > +	kfree(displays);
> > > +
> > > +	return display;
> > > +}
> > > +EXPORT_SYMBOL(drm_client_display_get_first_enabled);
> > > +
> > > +unsigned int
> > > +drm_client_display_preferred_depth(struct drm_client_display *display)
> > > +{
> > > +	struct drm_connector *conn;
> > > +	unsigned int ret;
> > > +
> > > +	conn = drm_connector_lookup(display->client->dev, NULL,
> > > +				    display->connectors[0]->conn_id);
> > > +	if (!conn)
> > > +		return 0;
> > > +
> > > +	if (conn->cmdline_mode.bpp_specified)
> > > +		ret = conn->cmdline_mode.bpp;
> > > +	else
> > > +		ret = display->client->dev->mode_config.preferred_depth;
> > > +
> > > +	drm_connector_put(conn);
> > > +
> > > +	return ret;
> > > +}
> > > +EXPORT_SYMBOL(drm_client_display_preferred_depth);
> > > +
> > > +int drm_client_display_dpms(struct drm_client_display *display, int mode)
> > > +{
> > > +	struct drm_mode_obj_set_property prop;
> > > +
> > > +	prop.value = mode;
> > > +	prop.prop_id = display->client->dev->mode_config.dpms_property->base.id;
> > > +	prop.obj_id = display->connectors[0]->conn_id;
> > > +	prop.obj_type = DRM_MODE_OBJECT_CONNECTOR;
> > > +
> > > +	return drm_mode_obj_set_property(display->client->dev, &prop,
> > > +					 display->client->file);
> > > +}
> > > +EXPORT_SYMBOL(drm_client_display_dpms);
> > > +
> > > +int drm_client_display_wait_vblank(struct drm_client_display *display)
> > > +{
> > > +	struct drm_crtc *crtc;
> > > +	union drm_wait_vblank vblank_req = {
> > > +		.request = {
> > > +			.type = _DRM_VBLANK_RELATIVE,
> > > +			.sequence = 1,
> > > +		},
> > > +	};
> > > +
> > > +	crtc = drm_crtc_find(display->client->dev, display->client->file,
> > > +			     display->connectors[0]->crtc_id);
> > > +	if (!crtc)
> > > +		return -ENOENT;
> > > +
> > > +	vblank_req.request.type |= drm_crtc_index(crtc) << _DRM_VBLANK_HIGH_CRTC_SHIFT;
> > > +
> > > +	return drm_wait_vblank(display->client->dev, &vblank_req,
> > > +			       display->client->file);
> > > +}
> > > +EXPORT_SYMBOL(drm_client_display_wait_vblank);
> > > +
> > > +static int drm_client_get_crtc_index(struct drm_client_dev *client, u32 id)
> > > +{
> > > +	int i;
> > > +
> > > +	for (i = 0; i < client->num_crtcs; i++)
> > > +		if (client->crtcs[i] == id)
> > > +			return i;
> > > +
> > > +	return -ENOENT;
> > > +}
> > > +
> > > +static int drm_client_display_find_crtcs(struct drm_client_display *display)
> > > +{
> > > +	struct drm_client_dev *client = display->client;
> > > +	struct drm_device *dev = client->dev;
> > > +	struct drm_file *file = client->file;
> > > +	u32 encoder_ids[DRM_CONNECTOR_MAX_ENCODER];
> > > +	unsigned int i, j, available_crtcs = ~0;
> > > +	struct drm_mode_get_connector conn_req;
> > > +	struct drm_mode_get_encoder enc_req;
> > > +	int ret;
> > > +
> > > +	/* Already done? */
> > > +	if (display->connectors[0]->crtc_id)
> > > +		return 0;
> > > +
> > > +	for (i = 0; i < display->num_connectors; i++) {
> > > +		u32 active_crtcs = 0, crtcs_for_connector = 0;
> > > +		int crtc_idx;
> > > +
> > > +		memset(&conn_req, 0, sizeof(conn_req));
> > > +		conn_req.connector_id = display->connectors[i]->conn_id;
> > > +		conn_req.encoders_ptr = (unsigned long)(encoder_ids);
> > > +		conn_req.count_encoders = DRM_CONNECTOR_MAX_ENCODER;
> > > +		ret = drm_mode_getconnector(dev, &conn_req, file, false);
> > > +		if (ret)
> > > +			return ret;
> > > +
> > > +		if (conn_req.encoder_id) {
> > > +			memset(&enc_req, 0, sizeof(enc_req));
> > > +			enc_req.encoder_id = conn_req.encoder_id;
> > > +			ret = drm_mode_getencoder(dev, &enc_req, file);
> > > +			if (ret)
> > > +				return ret;
> > > +			crtcs_for_connector |= enc_req.possible_crtcs;
> > > +			if (crtcs_for_connector & available_crtcs)
> > > +				goto found;
> > > +		}
> > > +
> > > +		for (j = 0; j < conn_req.count_encoders; j++) {
> > > +			memset(&enc_req, 0, sizeof(enc_req));
> > > +			enc_req.encoder_id = encoder_ids[j];
> > > +			ret = drm_mode_getencoder(dev, &enc_req, file);
> > > +			if (ret)
> > > +				return ret;
> > > +
> > > +			crtcs_for_connector |= enc_req.possible_crtcs;
> > > +
> > > +			if (enc_req.crtc_id) {
> > > +				crtc_idx = drm_client_get_crtc_index(client, enc_req.crtc_id);
> > > +				if (crtc_idx >= 0)
> > > +					active_crtcs |= 1 << crtc_idx;
> > > +			}
> > > +		}
> > > +
> > > +found:
> > > +		crtcs_for_connector &= available_crtcs;
> > > +		active_crtcs &= available_crtcs;
> > > +
> > > +		if (!crtcs_for_connector)
> > > +			return -ENOENT;
> > > +
> > > +		if (active_crtcs)
> > > +			crtc_idx = ffs(active_crtcs) - 1;
> > > +		else
> > > +			crtc_idx = ffs(crtcs_for_connector) - 1;
> > > +
> > > +		if (crtc_idx >= client->num_crtcs)
> > > +			return -EINVAL;
> > > +
> > > +		display->connectors[i]->crtc_id = client->crtcs[crtc_idx];
> > > +		available_crtcs &= ~BIT(crtc_idx);
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +/**
> > > + * drm_client_display_commit_mode - Commit a mode to the crtc(s)
> > > + * @display: Client display
> > > + * @fb_id: Framebuffer id
> > > + * @mode: Video mode
> > > + *
> > > + * Returns:
> > > + * Zero on success, negative error code on failure.
> > > + */
> > > +int drm_client_display_commit_mode(struct drm_client_display *display,
> > > +				   u32 fb_id, struct drm_mode_modeinfo *mode)
> > > +{
> > > +	struct drm_client_dev *client = display->client;
> > > +	struct drm_device *dev = client->dev;
> > > +	unsigned int num_crtcs = client->num_crtcs;
> > > +	struct drm_file *file = client->file;
> > > +	unsigned int *xoffsets = NULL, *yoffsets = NULL;
> > > +	struct drm_mode_crtc *crtc_reqs, *req;
> > > +	u32 cloned_conn_ids[2];
> > > +	unsigned int i;
> > > +	int idx, ret;
> > > +
> > > +	ret = drm_client_display_find_crtcs(display);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	crtc_reqs = kcalloc(num_crtcs, sizeof(*crtc_reqs), GFP_KERNEL);
> > > +	if (!crtc_reqs)
> > > +		return -ENOMEM;
> > > +
> > > +	for (i = 0; i < num_crtcs; i++)
> > > +		crtc_reqs[i].crtc_id = client->crtcs[i];
> > > +
> > > +	if (drm_client_display_is_tiled(display)) {
> > > +		/* TODO calculate tile crtc offsets */
> > > +	}
> > > +
> > > +	for (i = 0; i < display->num_connectors; i++) {
> > > +		idx = drm_client_get_crtc_index(client, display->connectors[i]->crtc_id);
> > > +		if (idx < 0)
> > > +			return -ENOENT;
> > > +
> > > +		req = &crtc_reqs[idx];
> > > +
> > > +		req->fb_id = fb_id;
> > > +		if (xoffsets) {
> > > +			req->x = xoffsets[i];
> > > +			req->y = yoffsets[i];
> > > +		}
> > > +		req->mode_valid = 1;
> > > +		req->mode = *mode;
> > > +
> > > +		if (display->cloned) {
> > > +			cloned_conn_ids[0] = display->connectors[0]->conn_id;
> > > +			cloned_conn_ids[1] = display->connectors[1]->conn_id;
> > > +			req->set_connectors_ptr = (unsigned long)(cloned_conn_ids);
> > > +			req->count_connectors = 2;
> > > +			break;
> > > +		}
> > > +
> > > +		req->set_connectors_ptr = (unsigned long)(&display->connectors[i]->conn_id);
> > > +		req->count_connectors = 1;
> > > +	}
> > > +
> > > +	for (i = 0; i < num_crtcs; i++) {
> > > +		ret = drm_mode_setcrtc(dev, &crtc_reqs[i], file, false);
> > > +		if (ret)
> > > +			break;
> > > +	}
> > > +
> > > +	kfree(xoffsets);
> > > +	kfree(yoffsets);
> > > +	kfree(crtc_reqs);
> > > +
> > > +	return ret;
> > > +}
> > > +EXPORT_SYMBOL(drm_client_display_commit_mode);
> > > +
> > > +unsigned int drm_client_display_current_fb(struct drm_client_display *display)
> > > +{
> > > +	struct drm_client_dev *client = display->client;
> > > +	int ret;
> > > +	struct drm_mode_crtc crtc_req = {
> > > +		.crtc_id = display->connectors[0]->crtc_id,
> > > +	};
> > > +
> > > +	ret = drm_mode_getcrtc(client->dev, &crtc_req, client->file);
> > > +	if (ret)
> > > +		return 0;
> > > +
> > > +	return crtc_req.fb_id;
> > > +}
> > > +EXPORT_SYMBOL(drm_client_display_current_fb);
> > > +
> > > +int drm_client_display_flush(struct drm_client_display *display, u32 fb_id,
> > > +			     struct drm_clip_rect *clips, unsigned int num_clips)
> > > +{
> > > +	struct drm_client_dev *client = display->client;
> > > +	struct drm_mode_fb_dirty_cmd dirty_req = {
> > > +		.fb_id = fb_id,
> > > +		.clips_ptr = (unsigned long)clips,
> > > +		.num_clips = num_clips,
> > > +	};
> > > +	int ret;
> > > +
> > > +	if (display->no_flushing)
> > > +		return 0;
> > > +
> > > +	ret = drm_mode_dirtyfb(client->dev, &dirty_req, client->file, false);
> > > +	if (ret == -ENOSYS) {
> > > +		ret = 0;
> > > +		display->no_flushing = true;
> > > +	}
> > > +
> > > +	return ret;
> > > +}
> > > +EXPORT_SYMBOL(drm_client_display_flush);
> > > +
> > > +int drm_client_display_page_flip(struct drm_client_display *display, u32 fb_id,
> > > +				 bool event)
> > > +{
> > > +	struct drm_client_dev *client = display->client;
> > > +	struct drm_mode_crtc_page_flip_target page_flip_req = {
> > > +		.crtc_id = display->connectors[0]->crtc_id,
> > > +		.fb_id = fb_id,
> > > +	};
> > > +
> > > +	if (event)
> > > +		page_flip_req.flags = DRM_MODE_PAGE_FLIP_EVENT;
> > > +
> > > +	return drm_mode_page_flip(client->dev, &page_flip_req, client->file);
> > > +	/*
> > > +	 * TODO:
> > > +	 * Where do we flush on page flip? Should the driver handle that?
> > > +	 */
> > > +}
> > > +EXPORT_SYMBOL(drm_client_display_page_flip);
> > > +
> > > +/**
> > > + * drm_client_framebuffer_create - Create a client framebuffer
> > > + * @client: DRM client
> > > + * @mode: Display mode to create a buffer for
> > > + * @format: Buffer format
> > > + *
> > > + * This function creates a &drm_client_buffer which consists of a
> > > + * &drm_framebuffer backed by a dumb buffer. The dumb buffer is &dma_buf
> > > + * exported to aquire a virtual address which is stored in
> > > + * &drm_client_buffer->vaddr.
> > > + * Call drm_client_framebuffer_delete() to free the buffer.
> > > + *
> > > + * Returns:
> > > + * Pointer to a client buffer or an error pointer on failure.
> > > + */
> > > +struct drm_client_buffer *
> > > +drm_client_framebuffer_create(struct drm_client_dev *client,
> > > +			      struct drm_mode_modeinfo *mode, u32 format)
> > > +{
> > > +	struct drm_client_buffer *buffer;
> > > +	int ret;
> > > +
> > > +	buffer = drm_client_buffer_create(client, mode->hdisplay,
> > > +					  mode->vdisplay, format);
> > > +	if (IS_ERR(buffer))
> > > +		return buffer;
> > > +
> > > +	ret = drm_client_buffer_addfb(buffer, mode);
> > > +	if (ret) {
> > > +		drm_client_buffer_delete(buffer);
> > > +		return ERR_PTR(ret);
> > > +	}
> > > +
> > > +	return buffer;
> > > +}
> > > +EXPORT_SYMBOL(drm_client_framebuffer_create);
> > > +
> > > +void drm_client_framebuffer_delete(struct drm_client_buffer *buffer)
> > > +{
> > > +	drm_client_buffer_rmfb(buffer);
> > > +	drm_client_buffer_delete(buffer);
> > > +}
> > > +EXPORT_SYMBOL(drm_client_framebuffer_delete);
> > > +
> > > +struct drm_client_buffer *
> > > +drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height,
> > > +			 u32 format)
> > > +{
> > > +	struct drm_mode_create_dumb dumb_args = { 0 };
> > > +	struct drm_prime_handle prime_args = { 0 };
> > > +	struct drm_client_buffer *buffer;
> > > +	struct dma_buf *dma_buf;
> > > +	void *vaddr;
> > > +	int ret;
> > > +
> > > +	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
> > > +	if (!buffer)
> > > +		return ERR_PTR(-ENOMEM);
> > > +
> > > +	ret = drm_client_get_file(client);
> > > +	if (ret)
> > > +		goto err_free;
> > > +
> > > +	buffer->client = client;
> > > +	buffer->width = width;
> > > +	buffer->height = height;
> > > +	buffer->format = format;
> > > +
> > > +	dumb_args.width = buffer->width;
> > > +	dumb_args.height = buffer->height;
> > > +	dumb_args.bpp = drm_format_plane_cpp(format, 0) * 8;
> > > +	ret = drm_mode_create_dumb(client->dev, &dumb_args, client->file);
> > > +	if (ret)
> > > +		goto err_put_file;
> > > +
> > > +	buffer->handle = dumb_args.handle;
> > > +	buffer->pitch = dumb_args.pitch;
> > > +	buffer->size = dumb_args.size;
> > > +
> > > +	prime_args.handle = dumb_args.handle;
> > > +	ret = drm_prime_handle_to_fd(client->dev, &prime_args, client->file);
> > > +	if (ret)
> > > +		goto err_delete;
> > > +
> > > +	dma_buf = dma_buf_get(prime_args.fd);
> > > +	if (IS_ERR(dma_buf)) {
> > > +		ret = PTR_ERR(dma_buf);
> > > +		goto err_delete;
> > > +	}
> > > +
> > > +	buffer->dma_buf = dma_buf;
> > > +
> > > +	vaddr = dma_buf_vmap(dma_buf);
> > > +	if (!vaddr) {
> > > +		ret = -ENOMEM;
> > > +		goto err_delete;
> > > +	}
> > > +
> > > +	buffer->vaddr = vaddr;
> > > +
> > > +	return buffer;
> > > +
> > > +err_delete:
> > > +	drm_client_buffer_delete(buffer);
> > > +err_put_file:
> > > +	drm_client_put_file(client);
> > > +err_free:
> > > +	kfree(buffer);
> > > +
> > > +	return ERR_PTR(ret);
> > > +}
> > > +EXPORT_SYMBOL(drm_client_buffer_create);
> > > +
> > > +void drm_client_buffer_delete(struct drm_client_buffer *buffer)
> > > +{
> > > +	if (!buffer)
> > > +		return;
> > > +
> > > +	if (buffer->vaddr)
> > > +		dma_buf_vunmap(buffer->dma_buf, buffer->vaddr);
> > > +
> > > +	if (buffer->dma_buf)
> > > +		dma_buf_put(buffer->dma_buf);
> > > +
> > > +	drm_mode_destroy_dumb(buffer->client->dev, buffer->handle,
> > > +			      buffer->client->file);
> > > +	drm_client_put_file(buffer->client);
> > > +	kfree(buffer);
> > > +}
> > > +EXPORT_SYMBOL(drm_client_buffer_delete);
> > > +
> > > +int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
> > > +			    struct drm_mode_modeinfo *mode)
> > > +{
> > > +	struct drm_client_dev *client = buffer->client;
> > > +	struct drm_mode_fb_cmd2 fb_req = { };
> > > +	unsigned int num_fbs, *fb_ids;
> > > +	int i, ret;
> > > +
> > > +	if (buffer->num_fbs)
> > > +		return -EINVAL;
> > > +
> > > +	if (mode->hdisplay > buffer->width || mode->vdisplay > buffer->height)
> > > +		return -EINVAL;
> > > +
> > > +	num_fbs = buffer->height / mode->vdisplay;
> > > +	fb_ids = kcalloc(num_fbs, sizeof(*fb_ids), GFP_KERNEL);
> > > +	if (!fb_ids)
> > > +		return -ENOMEM;
> > > +
> > > +	fb_req.width = mode->hdisplay;
> > > +	fb_req.height = mode->vdisplay;
> > > +	fb_req.pixel_format = buffer->format;
> > > +	fb_req.handles[0] = buffer->handle;
> > > +	fb_req.pitches[0] = buffer->pitch;
> > > +
> > > +	for (i = 0; i < num_fbs; i++) {
> > > +		fb_req.offsets[0] = i * mode->vdisplay * buffer->pitch;
> > > +		ret = drm_mode_addfb2(client->dev, &fb_req, client->file,
> > > +				      client->funcs->name);
> > > +		if (ret)
> > > +			goto err_remove;
> > > +		fb_ids[i] = fb_req.fb_id;
> > > +	}
> > > +
> > > +	buffer->fb_ids = fb_ids;
> > > +	buffer->num_fbs = num_fbs;
> > > +
> > > +	return 0;
> > > +
> > > +err_remove:
> > > +	for (i--; i >= 0; i--)
> > > +		drm_mode_rmfb(client->dev, fb_ids[i], client->file);
> > > +	kfree(fb_ids);
> > > +
> > > +	return ret;
> > > +}
> > > +EXPORT_SYMBOL(drm_client_buffer_addfb);
> > > +
> > > +int drm_client_buffer_rmfb(struct drm_client_buffer *buffer)
> > > +{
> > > +	unsigned int i;
> > > +	int ret;
> > > +
> > > +	if (!buffer || !buffer->num_fbs)
> > > +		return 0;
> > > +
> > > +	for (i = 0; i < buffer->num_fbs; i++) {
> > > +		ret = drm_mode_rmfb(buffer->client->dev, buffer->fb_ids[i],
> > > +				    buffer->client->file);
> > > +		if (ret)
> > > +			DRM_DEV_ERROR(buffer->client->dev->dev,
> > > +				      "Error removing FB:%u (%d)\n",
> > > +				      buffer->fb_ids[i], ret);
> > > +	}
> > > +
> > > +	kfree(buffer->fb_ids);
> > > +	buffer->fb_ids = NULL;
> > > +	buffer->num_fbs = 0;
> > > +
> > > +	return 0;
> > > +}
> > > +EXPORT_SYMBOL(drm_client_buffer_rmfb);
> > > diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> > > index f869de185986..db161337d87c 100644
> > > --- a/drivers/gpu/drm/drm_drv.c
> > > +++ b/drivers/gpu/drm/drm_drv.c
> > > @@ -33,6 +33,7 @@
> > >   #include <linux/mount.h>
> > >   #include <linux/slab.h>
> > > +#include <drm/drm_client.h>
> > >   #include <drm/drm_drv.h>
> > >   #include <drm/drmP.h>
> > > @@ -463,6 +464,7 @@ int drm_dev_init(struct drm_device *dev,
> > >   	dev->driver = driver;
> > >   	INIT_LIST_HEAD(&dev->filelist);
> > > +	INIT_LIST_HEAD(&dev->filelist_internal);
> > >   	INIT_LIST_HEAD(&dev->ctxlist);
> > >   	INIT_LIST_HEAD(&dev->vmalist);
> > >   	INIT_LIST_HEAD(&dev->maplist);
> > > @@ -787,6 +789,8 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags)
> > >   		 dev->dev ? dev_name(dev->dev) : "virtual device",
> > >   		 dev->primary->index);
> > > +	drm_client_dev_register(dev);
> > > +
> > >   	goto out_unlock;
> > >   err_minors:
> > > @@ -839,6 +843,8 @@ void drm_dev_unregister(struct drm_device *dev)
> > >   	drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
> > >   	drm_minor_unregister(dev, DRM_MINOR_RENDER);
> > >   	drm_minor_unregister(dev, DRM_MINOR_CONTROL);
> > > +
> > > +	drm_client_dev_unregister(dev);
> > >   }
> > >   EXPORT_SYMBOL(drm_dev_unregister);
> > > diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
> > > index 55505378df47..bcc688e58776 100644
> > > --- a/drivers/gpu/drm/drm_file.c
> > > +++ b/drivers/gpu/drm/drm_file.c
> > > @@ -35,6 +35,7 @@
> > >   #include <linux/slab.h>
> > >   #include <linux/module.h>
> > > +#include <drm/drm_client.h>
> > >   #include <drm/drm_file.h>
> > >   #include <drm/drmP.h>
> > > @@ -443,6 +444,8 @@ void drm_lastclose(struct drm_device * dev)
> > >   	if (drm_core_check_feature(dev, DRIVER_LEGACY))
> > >   		drm_legacy_dev_reinit(dev);
> > > +
> > > +	drm_client_dev_lastclose(dev);
> > >   }
> > >   /**
> > > diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
> > > index 2d1643bdae78..5d2a6c6717f5 100644
> > > --- a/drivers/gpu/drm/drm_probe_helper.c
> > > +++ b/drivers/gpu/drm/drm_probe_helper.c
> > > @@ -33,6 +33,7 @@
> > >   #include <linux/moduleparam.h>
> > >   #include <drm/drmP.h>
> > > +#include <drm/drm_client.h>
> > >   #include <drm/drm_crtc.h>
> > >   #include <drm/drm_fourcc.h>
> > >   #include <drm/drm_crtc_helper.h>
> > > @@ -563,6 +564,8 @@ void drm_kms_helper_hotplug_event(struct drm_device *dev)
> > >   	drm_sysfs_hotplug_event(dev);
> > >   	if (dev->mode_config.funcs->output_poll_changed)
> > >   		dev->mode_config.funcs->output_poll_changed(dev);
> > > +
> > > +	drm_client_dev_hotplug(dev);
> > >   }
> > >   EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
> > > diff --git a/include/drm/drm_client.h b/include/drm/drm_client.h
> > > new file mode 100644
> > > index 000000000000..88f6f87919c5
> > > --- /dev/null
> > > +++ b/include/drm/drm_client.h
> > > @@ -0,0 +1,192 @@
> > > +/* SPDX-License-Identifier: GPL-2.0 */
> > > +
> > > +#include <linux/mutex.h>
> > > +
> > > +struct dma_buf;
> > > +struct drm_clip_rect;
> > > +struct drm_device;
> > > +struct drm_file;
> > > +struct drm_mode_modeinfo;
> > > +
> > > +struct drm_client_dev;
> > > +
> > > +/**
> > > + * struct drm_client_funcs - DRM client  callbacks
> > > + */
> > > +struct drm_client_funcs {
> > > +	/**
> > > +	 * @name:
> > > +	 *
> > > +	 * Name of the client.
> > > +	 */
> > > +	const char *name;
> > > +
> > > +	/**
> > > +	 * @new:
> > > +	 *
> > > +	 * Called when a client or a &drm_device is registered.
> > > +	 * If the callback returns anything but zero, then this client instance
> > > +	 * is dropped.
> > > +	 *
> > > +	 * This callback is mandatory.
> > > +	 */
> > > +	int (*new)(struct drm_client_dev *client);
> > > +
> > > +	/**
> > > +	 * @remove:
> > > +	 *
> > > +	 * Called when a &drm_device is unregistered or the client is
> > > +	 * unregistered. If zero is returned drm_client_free() is called
> > > +	 * automatically. If the client can't drop it's resources it should
> > > +	 * return non-zero and call drm_client_free() later.
> > > +	 *
> > > +	 * This callback is optional.
> > > +	 */
> > > +	int (*remove)(struct drm_client_dev *client);
> > > +
> > > +	/**
> > > +	 * @lastclose:
> > > +	 *
> > > +	 * Called on drm_lastclose(). The first client instance in the list
> > > +	 * that returns zero gets the privilege to restore and no more clients
> > > +	 * are called.
> > > +	 *
> > > +	 * This callback is optional.
> > > +	 */
> > > +	int (*lastclose)(struct drm_client_dev *client);
> > > +
> > > +	/**
> > > +	 * @hotplug:
> > > +	 *
> > > +	 * Called on drm_kms_helper_hotplug_event().
> > > +	 *
> > > +	 * This callback is optional.
> > > +	 */
> > > +	int (*hotplug)(struct drm_client_dev *client);
> > > +
> > > +// TODO
> > > +//	void (*suspend)(struct drm_client_dev *client);
> > > +//	void (*resume)(struct drm_client_dev *client);
> > > +};
> > > +
> > > +/**
> > > + * struct drm_client_dev - DRM client instance
> > > + */
> > > +struct drm_client_dev {
> > > +	struct list_head list;
> > > +	struct drm_device *dev;
> > > +	const struct drm_client_funcs *funcs;
> > > +	struct mutex lock;
> > > +	struct drm_file *file;
> > > +	unsigned int file_ref_count;
> > > +	u32 *crtcs;
> > > +	unsigned int num_crtcs;
> > > +	u32 min_width;
> > > +	u32 max_width;
> > > +	u32 min_height;
> > > +	u32 max_height;
> > > +	void *private;
> > > +};
> > > +
> > > +void drm_client_free(struct drm_client_dev *client);
> > > +int drm_client_register(const struct drm_client_funcs *funcs);
> > > +void drm_client_unregister(const struct drm_client_funcs *funcs);
> > > +
> > > +void drm_client_dev_register(struct drm_device *dev);
> > > +void drm_client_dev_unregister(struct drm_device *dev);
> > > +void drm_client_dev_hotplug(struct drm_device *dev);
> > > +void drm_client_dev_lastclose(struct drm_device *dev);
> > > +
> > > +int drm_client_get_file(struct drm_client_dev *client);
> > > +void drm_client_put_file(struct drm_client_dev *client);
> > > +struct drm_event *
> > > +drm_client_read_event(struct drm_client_dev *client, bool block);
> > > +
> > > +struct drm_client_connector {
> > > +	unsigned int conn_id;
> > > +	unsigned int status;
> > > +	unsigned int crtc_id;
> > > +	struct drm_mode_modeinfo *modes;
> > > +	unsigned int num_modes;
> > > +	bool has_tile;
> > > +	int tile_group;
> > > +	u8 tile_h_loc, tile_v_loc;
> > > +};
> > > +
> > > +struct drm_client_display {
> > > +	struct drm_client_dev *client;
> > > +
> > > +	struct drm_client_connector **connectors;
> > > +	unsigned int num_connectors;
> > > +
> > > +	struct mutex modes_lock;
> > > +	struct drm_mode_modeinfo *modes;
> > > +	unsigned int num_modes;
> > > +
> > > +	bool cloned;
> > > +	bool no_flushing;
> > > +};
> > > +
> > > +void drm_client_display_free(struct drm_client_display *display);
> > > +struct drm_client_display *
> > > +drm_client_display_get_first_enabled(struct drm_client_dev *client, bool strict);
> > > +
> > > +int drm_client_display_update_modes(struct drm_client_display *display,
> > > +				    bool *mode_changed);
> > > +
> > > +static inline bool
> > > +drm_client_display_is_tiled(struct drm_client_display *display)
> > > +{
> > > +	return !display->cloned && display->num_connectors > 1;
> > > +}
> > > +
> > > +int drm_client_display_dpms(struct drm_client_display *display, int mode);
> > > +int drm_client_display_wait_vblank(struct drm_client_display *display);
> > > +
> > > +struct drm_mode_modeinfo *
> > > +drm_client_display_first_mode(struct drm_client_display *display);
> > > +struct drm_mode_modeinfo *
> > > +drm_client_display_next_mode(struct drm_client_display *display,
> > > +			     struct drm_mode_modeinfo *mode);
> > > +
> > > +#define drm_client_display_for_each_mode(display, mode) \
> > > +	for (mode = drm_client_display_first_mode(display); mode; \
> > > +	     mode = drm_client_display_next_mode(display, mode))
> > > +
> > > +unsigned int
> > > +drm_client_display_preferred_depth(struct drm_client_display *display);
> > > +
> > > +int drm_client_display_commit_mode(struct drm_client_display *display,
> > > +				   u32 fb_id, struct drm_mode_modeinfo *mode);
> > > +unsigned int drm_client_display_current_fb(struct drm_client_display *display);
> > > +int drm_client_display_flush(struct drm_client_display *display, u32 fb_id,
> > > +			     struct drm_clip_rect *clips, unsigned int num_clips);
> > > +int drm_client_display_page_flip(struct drm_client_display *display, u32 fb_id,
> > > +				 bool event);
> > > +
> > > +struct drm_client_buffer {
> > > +	struct drm_client_dev *client;
> > > +	u32 width;
> > > +	u32 height;
> > > +	u32 format;
> > > +	u32 handle;
> > > +	u32 pitch;
> > > +	u64 size;
> > > +	struct dma_buf *dma_buf;
> > > +	void *vaddr;
> > > +
> > > +	unsigned int *fb_ids;
> > > +	unsigned int num_fbs;
> > > +};
> > > +
> > > +struct drm_client_buffer *
> > > +drm_client_framebuffer_create(struct drm_client_dev *client,
> > > +			      struct drm_mode_modeinfo *mode, u32 format);
> > > +void drm_client_framebuffer_delete(struct drm_client_buffer *buffer);
> > > +struct drm_client_buffer *
> > > +drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height,
> > > +			 u32 format);
> > > +void drm_client_buffer_delete(struct drm_client_buffer *buffer);
> > > +int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
> > > +			    struct drm_mode_modeinfo *mode);
> > > +int drm_client_buffer_rmfb(struct drm_client_buffer *buffer);
> > > diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h
> > > index 7c4fa32f3fc6..32dfed3d5a86 100644
> > > --- a/include/drm/drm_device.h
> > > +++ b/include/drm/drm_device.h
> > > @@ -67,6 +67,7 @@ struct drm_device {
> > >   	struct mutex filelist_mutex;
> > >   	struct list_head filelist;
> > > +	struct list_head filelist_internal;
> > >   	/** \name Memory management */
> > >   	/*@{ */
> > > diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
> > > index 5176c3797680..39af8a4be7b3 100644
> > > --- a/include/drm/drm_file.h
> > > +++ b/include/drm/drm_file.h
> > > @@ -248,6 +248,13 @@ struct drm_file {
> > >   	 */
> > >   	void *driver_priv;
> > > +	/**
> > > +	 * @user_priv:
> > > +	 *
> > > +	 * Optional pointer for user private data. Useful for in-kernel clients.
> > > +	 */
> > > +	void *user_priv;
> > > +
> > >   	/**
> > >   	 * @fbs:
> > >   	 *
> > > -- 
> > > 2.15.1
> > > 
>

Noralf Trønnes March 12, 2018, 8:21 p.m. UTC | #4

Den 12.03.2018 17.51, skrev Daniel Vetter:
> On Thu, Mar 08, 2018 at 06:12:11PM +0100, Noralf Tr??nnes wrote:
>> Den 06.03.2018 09.56, skrev Daniel Vetter:
>>> On Thu, Feb 22, 2018 at 09:06:50PM +0100, Noralf Tr??nnes wrote:
>>>> This adds an API for writing in-kernel clients.
>>>>
>>>> TODO:
>>>> - Flesh out and complete documentation.
>>>> - Cloned displays is not tested.
>>>> - Complete tiled display support and test it.
>>>> - Test plug/unplug different monitors.
>>>> - A runtime knob to prevent clients from attaching for debugging purposes.
>>>> - Maybe a way to unbind individual client instances.
>>>> - Maybe take the sysrq support in drm_fb_helper and move it here somehow.
>>>> - Add suspend/resume callbacks.
>>>>     Does anyone know why fbdev requires suspend/resume?
>>>>
>>>> Signed-off-by: Noralf Tr??nnes <[e-mail]>
>>> The core client api I like. Some of the opens I'm seeing:
>>>
>>> - If we go with using the internal kms api directly instead of IOCTL
>>>     wrappers then a huge pile of the functions you have here aren't needed
>>>     (e.g. all the event stuff we can just directly use vblank events instead
>>>     of all the wrapping). I'm leaning ever more into that direction, since
>>>     much less code to add.
>> Looking at drm_fb_helper once again I now see an opportunity to simplify
>> the modesetting code by nuking drm_fb_helper_connector and stop
>> maintaining an array of connectors. It looks to be possible to just
>> create an array temporarily in drm_setup_crtcs() for the duration of the
>> function. The connectors we care about are ref counted and attached to
>> modesets. This would remove the need for drm_fb_helper_add_one_connector().
>>
>> So I might be able to do struct drm_fb_helper_crtc -> drm_client_crtc
>> and let the client API take over drm_setup_crtcs(). I'll give it a try.
> I'm more wondering why we need drm_client_crtc at all, why is drm_crtc not
> good enough. Or maybe I'm missing something. Imo ioctl wrappers should be
> the exception where we really, really need them (because the backend of
> the ioctl isn't implemented in a generic way, e.g. dumb buffers), not for
> stuff where we already have a perfectly useable in-kernel abi (anything
> related to modesetting).

I was talking about moving the modesetting code from drm_fb_helper.c
to drm_client.c, which meant moving 'struct drm_fb_helper_crtc' as well.

struct drm_fb_helper_crtc {
     struct drm_mode_set mode_set;
     struct drm_display_mode *desired_mode;
     int x, y;
};

But maybe we can get rid of that struct as well.
The info it contains is also available in drm_mode_set:

static void drm_setup_crtcs(struct drm_fb_helper *fb_helper,
                 u32 width, u32 height)
{
...
     drm_fb_helper_for_each_connector(fb_helper, i) {
         struct drm_display_mode *mode = modes[i];
         struct drm_fb_helper_crtc *fb_crtc = crtcs[i];
         struct drm_fb_offset *offset = &offsets[i];

         if (mode && fb_crtc) {
             struct drm_mode_set *modeset = &fb_crtc->mode_set;

             fb_crtc->desired_mode = mode;
             fb_crtc->x = offset->x;
             fb_crtc->y = offset->y;
             modeset->mode = drm_mode_duplicate(dev,
                                fb_crtc->desired_mode);
             modeset->x = offset->x;
             modeset->y = offset->y;
         }
     }

I took the hint about my ioctl wrappers :-)

Noralf.

>
> And in a way the ioctl wrappers wouldn't really be ioctl wrappers
> conceptually, but simple share some of the same code with the ioctl call
> chain. The idea is to provide some minimal wrappar around the ->dumb*
> callbacks.
>
> Anything else is not needed, I think.
>
>> There is one challenge I see upfront and that's the i915 fb_helper
>> callback in drm_setup_crtcs().
>>
>>> - The register/unregister model needs more thought. Allowing both clients
>>>     to register whenever they want to, and drm_device instances to come and
>>>     go is what fbcon has done, and the resulting locking is a horror show.
>>>
>>>     I think if we require that all in-kernel drm_clients are registers when
>>>     loading drm.ko (and enabled/disabled only per module options and
>>>     Kconfig), then we can throw out all the locking. That avoids a lot of
>>>     the headaches.
>>>
>>>     2nd, if the list of clients is static over the lifetime of drm.ko, we
>>>     also don't need to iterate existing drivers. Which avoids me having to
>>>     review the iterator patch (that's the other aspect where fbcon totally
>>>     falls over and essentially just ignores a bunch of races).
>> Are you talking about linking the clients into drm.ko?
>>
>> drivers/gpu/drm/Makefile:
>>
>> drm-$(CONFIG_DRM_CLIENT_BOOTSPLASH) += client/drm_bootsplash.o
>>
>> drivers/gpu/drm/drm_drv.c:
>>
>> ??static int __init drm_core_init(void)
>> ??{
>> +?????? drm_bootsplash_register();
>> +?????? drm_fbdev_register();
>> ??}
>>
>> drivers/gpu/drm/drm_internal.h:
>>
>> #ifdef DRM_CLIENT_BOOTSPLASH
>> void drm_bootsplash_register(void);
>> #else
>> static inline void drm_bootsplash_register(void)
>> {
>> }
>> #endif
>>
>> drivers/gpu/drm/client/drm_bootsplash.c:
>>
>> static const struct drm_client_funcs drm_bootsplash_funcs = {
>> ?????? .name?????? ?????? = "drm_bootsplash",
>> ?????? .new?????? ?????? = drm_bootsplash_new,
>> ?????? .remove?????? ?????? = drm_bootsplash_remove,
>> ?????? .hotplug?????? = drm_bootsplash_hotplug,
>> };
>>
>> void drm_bootsplash_register(void)
>> {
>> ?????? drm_client_register(&drm_bootsplash_funcs);
>> }
>>
>> drivers/gpu/drm/drm_client.c:
>>
>> static LIST_HEAD(drm_client_funcs_list);
>>
>> void drm_client_register(const struct drm_client_funcs *funcs)
>> {
>> ?????? struct drm_client_funcs_entry *funcs_entry;
>>
>> ?????? funcs_entry = kzalloc(sizeof(*funcs_entry), GFP_KERNEL);
>> ?????? if (!funcs_entry) {
>> ?????? ?????? DRM_ERROR("Failed to register: %s\n", funcs->name);
>> ?????? ?????? return;
>> ?????? }
>>
>> ?????? funcs_entry->funcs = funcs;
>>
>> ?????? list_add(&funcs_entry->list, &drm_client_funcs_list);
>>
>> ?????? DRM_DEBUG_KMS("%s\n", funcs->name);
>> }
>>
>>
>> And each client having a runtime enable/disable knob:
>>
>> drivers/gpu/drm/client/drm_bootsplash.c:
>>
>> static bool drm_bootsplash_enabled = true;
>> module_param_named(bootsplash_enabled, drm_bootsplash_enabled, bool, 0600);
>> MODULE_PARM_DESC(bootsplash_enabled, "Enable bootsplash client
>> [default=true]");
>
> Yup, pretty much.
>
>> Simple USB Display
>> A few months back while looking at the udl shmem code, I got the idea
>> that I could turn a Raspberry Pi Zero into a $5 USB to HDMI/DSI/DPI/DBI/TV
>> adapter. The host side would be a simple tinydrm driver using the kernel
>> compression lib to speed up transfers. The gadget/device side would be a
>> userspace app decompressing the buffer into an exported dumb buffer.
>>
>> While working with this client API I realized that I could use it and
>> write a kernel gadget driver instead avoiding the challenge of going
>> back and forth to userspace with the framebuffer. For such a client I
>> would have preferred it to be a loadable module not linked into drm.ko
>> to increase the chance that distributions would enable it.
> I think that we can do as a loadable client, since you probably want some
> configfs interface to define which drm driver it should control. The
> reason behind the static list of built-in clients is purely for the
> auto-register stuff that we want for fbdev emulation and other things.
> Auto-registration where both sides can be loaded in any order is real pain
> wrt locking. Explicit registration where you can load both sides is
> totally fine and I think would cover your usb gadget display driver
> use-case.
>
> btw usb gadget driver to drive drm kms drivers sounds like a really cool
> thing.
> -Daniel
>
>> Noralf.
>>
>>>> ---
>>>>    drivers/gpu/drm/Kconfig             |    2 +
>>>>    drivers/gpu/drm/Makefile            |    3 +-
>>>>    drivers/gpu/drm/client/Kconfig      |    4 +
>>>>    drivers/gpu/drm/client/Makefile     |    1 +
>>>>    drivers/gpu/drm/client/drm_client.c | 1612 +++++++++++++++++++++++++++++++++++
>>> I'd move this into main drm/ directory, it's fairly core stuff.
>>>
>>>>    drivers/gpu/drm/drm_drv.c           |    6 +
>>>>    drivers/gpu/drm/drm_file.c          |    3 +
>>>>    drivers/gpu/drm/drm_probe_helper.c  |    3 +
>>>>    include/drm/drm_client.h            |  192 +++++
>>>>    include/drm/drm_device.h            |    1 +
>>>>    include/drm/drm_file.h              |    7 +
>>>>    11 files changed, 1833 insertions(+), 1 deletion(-)
>>>>    create mode 100644 drivers/gpu/drm/client/Kconfig
>>>>    create mode 100644 drivers/gpu/drm/client/Makefile
>>>>    create mode 100644 drivers/gpu/drm/client/drm_client.c
>>>>    create mode 100644 include/drm/drm_client.h
>>>>
>>>> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
>>>> index deeefa7a1773..d4ae15f9ee9f 100644
>>>> --- a/drivers/gpu/drm/Kconfig
>>>> +++ b/drivers/gpu/drm/Kconfig
>>>> @@ -154,6 +154,8 @@ config DRM_SCHED
>>>>    	tristate
>>>>    	depends on DRM
>>>> +source "drivers/gpu/drm/client/Kconfig"
>>>> +
>>>>    source "drivers/gpu/drm/i2c/Kconfig"
>>>>    source "drivers/gpu/drm/arm/Kconfig"
>>>> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
>>>> index 50093ff4479b..8e06dc7eeca1 100644
>>>> --- a/drivers/gpu/drm/Makefile
>>>> +++ b/drivers/gpu/drm/Makefile
>>>> @@ -18,7 +18,7 @@ drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
>>>>    		drm_encoder.o drm_mode_object.o drm_property.o \
>>>>    		drm_plane.o drm_color_mgmt.o drm_print.o \
>>>>    		drm_dumb_buffers.o drm_mode_config.o drm_vblank.o \
>>>> -		drm_syncobj.o drm_lease.o
>>>> +		drm_syncobj.o drm_lease.o client/drm_client.o
>>>>    drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o
>>>>    drm-$(CONFIG_DRM_VM) += drm_vm.o
>>>> @@ -103,3 +103,4 @@ obj-$(CONFIG_DRM_MXSFB)	+= mxsfb/
>>>>    obj-$(CONFIG_DRM_TINYDRM) += tinydrm/
>>>>    obj-$(CONFIG_DRM_PL111) += pl111/
>>>>    obj-$(CONFIG_DRM_TVE200) += tve200/
>>>> +obj-y			+= client/
>>>> diff --git a/drivers/gpu/drm/client/Kconfig b/drivers/gpu/drm/client/Kconfig
>>>> new file mode 100644
>>>> index 000000000000..4bb8e4655ff7
>>>> --- /dev/null
>>>> +++ b/drivers/gpu/drm/client/Kconfig
>>>> @@ -0,0 +1,4 @@
>>>> +menu "DRM Clients"
>>>> +	depends on DRM
>>>> +
>>>> +endmenu
>>>> diff --git a/drivers/gpu/drm/client/Makefile b/drivers/gpu/drm/client/Makefile
>>>> new file mode 100644
>>>> index 000000000000..f66554cd5c45
>>>> --- /dev/null
>>>> +++ b/drivers/gpu/drm/client/Makefile
>>>> @@ -0,0 +1 @@
>>>> +# SPDX-License-Identifier: GPL-2.0
>>>> diff --git a/drivers/gpu/drm/client/drm_client.c b/drivers/gpu/drm/client/drm_client.c
>>>> new file mode 100644
>>>> index 000000000000..a633bf747316
>>>> --- /dev/null
>>>> +++ b/drivers/gpu/drm/client/drm_client.c
>>>> @@ -0,0 +1,1612 @@
>>>> +// SPDX-License-Identifier: GPL-2.0
>>>> +// Copyright 2018 Noralf Tr??nnes
>>>> +
>>>> +#include <linux/dma-buf.h>
>>>> +#include <linux/list.h>
>>>> +#include <linux/mutex.h>
>>>> +#include <linux/module.h>
>>>> +#include <linux/slab.h>
>>>> +
>>>> +#include <drm/drm_client.h>
>>>> +#include <drm/drm_connector.h>
>>>> +#include <drm/drm_drv.h>
>>>> +#include <drm/drm_file.h>
>>>> +#include <drm/drm_ioctl.h>
>>>> +#include <drm/drmP.h>
>>>> +
>>>> +#include "drm_crtc_internal.h"
>>>> +#include "drm_internal.h"
>>>> +
>>>> +struct drm_client_funcs_entry {
>>>> +	struct list_head list;
>>>> +	const struct drm_client_funcs *funcs;
>>>> +};
>>>> +
>>>> +static LIST_HEAD(drm_client_list);
>>> I think the client list itself should be on the drm_device, not in one
>>> global list that mixes up all the clients of all the drm_devices.
>>>
>>> I'll skip reviewing details since we have a bunch of high-level questions
>>> to figure out first.
>>> -Daniel
>>>
>>>> +static LIST_HEAD(drm_client_funcs_list);
>>>> +static DEFINE_MUTEX(drm_client_list_lock);
>>>> +
>>>> +static void drm_client_new(struct drm_device *dev,
>>>> +			   const struct drm_client_funcs *funcs)
>>>> +{
>>>> +	struct drm_client_dev *client;
>>>> +	int ret;
>>>> +
>>>> +	lockdep_assert_held(&drm_client_list_lock);
>>>> +
>>>> +	client = kzalloc(sizeof(*client), GFP_KERNEL);
>>>> +	if (!client)
>>>> +		return;
>>>> +
>>>> +	mutex_init(&client->lock);
>>>> +	client->dev = dev;
>>>> +	client->funcs = funcs;
>>>> +
>>>> +	ret = funcs->new(client);
>>>> +	DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n", funcs->name, ret);
>>>> +	if (ret) {
>>>> +		drm_client_free(client);
>>>> +		return;
>>>> +	}
>>>> +
>>>> +	list_add(&client->list, &drm_client_list);
>>>> +}
>>>> +
>>>> +/**
>>>> + * drm_client_free - Free DRM client resources
>>>> + * @client: DRM client
>>>> + *
>>>> + * This is called automatically on client removal unless the client returns
>>>> + * non-zero in the &drm_client_funcs->remove callback. The fbdev client does
>>>> + * this when it can't close &drm_file because userspace has an open fd.
>>>> + */
>>>> +void drm_client_free(struct drm_client_dev *client)
>>>> +{
>>>> +	DRM_DEV_DEBUG_KMS(client->dev->dev, "%s\n", client->funcs->name);
>>>> +	if (WARN_ON(client->file)) {
>>>> +		client->file_ref_count = 1;
>>>> +		drm_client_put_file(client);
>>>> +	}
>>>> +	mutex_destroy(&client->lock);
>>>> +	kfree(client->crtcs);
>>>> +	kfree(client);
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_free);
>>>> +
>>>> +static void drm_client_remove(struct drm_client_dev *client)
>>>> +{
>>>> +	lockdep_assert_held(&drm_client_list_lock);
>>>> +
>>>> +	list_del(&client->list);
>>>> +
>>>> +	if (!client->funcs->remove || !client->funcs->remove(client))
>>>> +		drm_client_free(client);
>>>> +}
>>>> +
>>>> +/**
>>>> + * drm_client_register - Register a DRM client
>>>> + * @funcs: Client callbacks
>>>> + *
>>>> + * Returns:
>>>> + * Zero on success, negative error code on failure.
>>>> + */
>>>> +int drm_client_register(const struct drm_client_funcs *funcs)
>>>> +{
>>>> +	struct drm_client_funcs_entry *funcs_entry;
>>>> +	struct drm_device_list_iter iter;
>>>> +	struct drm_device *dev;
>>>> +
>>>> +	funcs_entry = kzalloc(sizeof(*funcs_entry), GFP_KERNEL);
>>>> +	if (!funcs_entry)
>>>> +		return -ENOMEM;
>>>> +
>>>> +	funcs_entry->funcs = funcs;
>>>> +
>>>> +	mutex_lock(&drm_global_mutex);
>>>> +	mutex_lock(&drm_client_list_lock);
>>>> +
>>>> +	drm_device_list_iter_begin(&iter);
>>>> +	drm_for_each_device_iter(dev, &iter)
>>>> +		if (drm_core_check_feature(dev, DRIVER_MODESET))
>>>> +			drm_client_new(dev, funcs);
>>>> +	drm_device_list_iter_end(&iter);
>>>> +
>>>> +	list_add(&funcs_entry->list, &drm_client_funcs_list);
>>>> +
>>>> +	mutex_unlock(&drm_client_list_lock);
>>>> +	mutex_unlock(&drm_global_mutex);
>>>> +
>>>> +	DRM_DEBUG_KMS("%s\n", funcs->name);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_register);
>>>> +
>>>> +/**
>>>> + * drm_client_unregister - Unregister a DRM client
>>>> + * @funcs: Client callbacks
>>>> + */
>>>> +void drm_client_unregister(const struct drm_client_funcs *funcs)
>>>> +{
>>>> +	struct drm_client_funcs_entry *funcs_entry;
>>>> +	struct drm_client_dev *client, *tmp;
>>>> +
>>>> +	mutex_lock(&drm_client_list_lock);
>>>> +
>>>> +	list_for_each_entry_safe(client, tmp, &drm_client_list, list) {
>>>> +		if (client->funcs == funcs)
>>>> +			drm_client_remove(client);
>>>> +	}
>>>> +
>>>> +	list_for_each_entry(funcs_entry, &drm_client_funcs_list, list) {
>>>> +		if (funcs_entry->funcs == funcs) {
>>>> +			list_del(&funcs_entry->list);
>>>> +			kfree(funcs_entry);
>>>> +			break;
>>>> +		}
>>>> +	}
>>>> +
>>>> +	mutex_unlock(&drm_client_list_lock);
>>>> +
>>>> +	DRM_DEBUG_KMS("%s\n", funcs->name);
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_unregister);
>>>> +
>>>> +void drm_client_dev_register(struct drm_device *dev)
>>>> +{
>>>> +	struct drm_client_funcs_entry *funcs_entry;
>>>> +
>>>> +	/*
>>>> +	 * Minors are created at the beginning of drm_dev_register(), but can
>>>> +	 * be removed again if the function fails. Since we iterate DRM devices
>>>> +	 * by walking DRM minors, we need to stay under this lock.
>>>> +	 */
>>>> +	lockdep_assert_held(&drm_global_mutex);
>>>> +
>>>> +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
>>>> +		return;
>>>> +
>>>> +	mutex_lock(&drm_client_list_lock);
>>>> +	list_for_each_entry(funcs_entry, &drm_client_funcs_list, list)
>>>> +		drm_client_new(dev, funcs_entry->funcs);
>>>> +	mutex_unlock(&drm_client_list_lock);
>>>> +}
>>>> +
>>>> +void drm_client_dev_unregister(struct drm_device *dev)
>>>> +{
>>>> +	struct drm_client_dev *client, *tmp;
>>>> +
>>>> +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
>>>> +		return;
>>>> +
>>>> +	mutex_lock(&drm_client_list_lock);
>>>> +	list_for_each_entry_safe(client, tmp, &drm_client_list, list)
>>>> +		if (client->dev == dev)
>>>> +			drm_client_remove(client);
>>>> +	mutex_unlock(&drm_client_list_lock);
>>>> +}
>>>> +
>>>> +void drm_client_dev_hotplug(struct drm_device *dev)
>>>> +{
>>>> +	struct drm_client_dev *client;
>>>> +	int ret;
>>>> +
>>>> +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
>>>> +		return;
>>>> +
>>>> +	mutex_lock(&drm_client_list_lock);
>>>> +	list_for_each_entry(client, &drm_client_list, list)
>>>> +		if (client->dev == dev && client->funcs->hotplug) {
>>>> +			ret = client->funcs->hotplug(client);
>>>> +			DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n",
>>>> +					  client->funcs->name, ret);
>>>> +		}
>>>> +	mutex_unlock(&drm_client_list_lock);
>>>> +}
>>>> +
>>>> +void drm_client_dev_lastclose(struct drm_device *dev)
>>>> +{
>>>> +	struct drm_client_dev *client;
>>>> +	int ret;
>>>> +
>>>> +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
>>>> +		return;
>>>> +
>>>> +	mutex_lock(&drm_client_list_lock);
>>>> +	list_for_each_entry(client, &drm_client_list, list)
>>>> +		if (client->dev == dev && client->funcs->lastclose) {
>>>> +			ret = client->funcs->lastclose(client);
>>>> +			DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n",
>>>> +					  client->funcs->name, ret);
>>>> +		}
>>>> +	mutex_unlock(&drm_client_list_lock);
>>>> +}
>>>> +
>>>> +/* Get static info */
>>>> +static int drm_client_init(struct drm_client_dev *client, struct drm_file *file)
>>>> +{
>>>> +	struct drm_mode_card_res card_res = {};
>>>> +	struct drm_device *dev = client->dev;
>>>> +	u32 *crtcs;
>>>> +	int ret;
>>>> +
>>>> +	ret = drm_mode_getresources(dev, &card_res, file, false);
>>>> +	if (ret)
>>>> +		return ret;
>>>> +	if (!card_res.count_crtcs)
>>>> +		return -ENOENT;
>>>> +
>>>> +	crtcs = kmalloc_array(card_res.count_crtcs, sizeof(*crtcs), GFP_KERNEL);
>>>> +	if (!crtcs)
>>>> +		return -ENOMEM;
>>>> +
>>>> +	card_res.count_fbs = 0;
>>>> +	card_res.count_connectors = 0;
>>>> +	card_res.count_encoders = 0;
>>>> +	card_res.crtc_id_ptr = (unsigned long)crtcs;
>>>> +
>>>> +	ret = drm_mode_getresources(dev, &card_res, file, false);
>>>> +	if (ret) {
>>>> +		kfree(crtcs);
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	client->crtcs = crtcs;
>>>> +	client->num_crtcs = card_res.count_crtcs;
>>>> +	client->min_width = card_res.min_width;
>>>> +	client->max_width = card_res.max_width;
>>>> +	client->min_height = card_res.min_height;
>>>> +	client->max_height = card_res.max_height;
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +/**
>>>> + * drm_client_get_file - Get a DRM file
>>>> + * @client: DRM client
>>>> + *
>>>> + * This function makes sure the client has a &drm_file available. The client
>>>> + * doesn't normally need to call this, since all client functions that depends
>>>> + * on a DRM file will call it. A matching call to drm_client_put_file() is
>>>> + * necessary.
>>>> + *
>>>> + * The reason for not opening a DRM file when a @client is created is because
>>>> + * we have to take a ref on the driver module due to &drm_driver->postclose
>>>> + * being called in drm_file_free(). Having a DRM file open for the lifetime of
>>>> + * the client instance would block driver module unload.
>>>> + *
>>>> + * Returns:
>>>> + * Zero on success, negative error code on failure.
>>>> + */
>>>> +int drm_client_get_file(struct drm_client_dev *client)
>>>> +{
>>>> +	struct drm_device *dev = client->dev;
>>>> +	struct drm_file *file;
>>>> +	int ret = 0;
>>>> +
>>>> +	mutex_lock(&client->lock);
>>>> +
>>>> +	if (client->file_ref_count++) {
>>>> +		mutex_unlock(&client->lock);
>>>> +		return 0;
>>>> +	}
>>>> +
>>>> +	if (!try_module_get(dev->driver->fops->owner)) {
>>>> +		ret = -ENODEV;
>>>> +		goto err_unlock;
>>>> +	}
>>>> +
>>>> +	drm_dev_get(dev);
>>>> +
>>>> +	file = drm_file_alloc(dev->primary);
>>>> +	if (IS_ERR(file)) {
>>>> +		ret = PTR_ERR(file);
>>>> +		goto err_put;
>>>> +	}
>>>> +
>>>> +	if (!client->crtcs) {
>>>> +		ret = drm_client_init(client, file);
>>>> +		if (ret)
>>>> +			goto err_free;
>>>> +	}
>>>> +
>>>> +	mutex_lock(&dev->filelist_mutex);
>>>> +	list_add(&file->lhead, &dev->filelist_internal);
>>>> +	mutex_unlock(&dev->filelist_mutex);
>>>> +
>>>> +	client->file = file;
>>>> +
>>>> +	mutex_unlock(&client->lock);
>>>> +
>>>> +	return 0;
>>>> +
>>>> +err_free:
>>>> +	drm_file_free(file);
>>>> +err_put:
>>>> +	drm_dev_put(dev);
>>>> +	module_put(dev->driver->fops->owner);
>>>> +err_unlock:
>>>> +	client->file_ref_count = 0;
>>>> +	mutex_unlock(&client->lock);
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_get_file);
>>>> +
>>>> +void drm_client_put_file(struct drm_client_dev *client)
>>>> +{
>>>> +	struct drm_device *dev = client->dev;
>>>> +
>>>> +	if (!client)
>>>> +		return;
>>>> +
>>>> +	mutex_lock(&client->lock);
>>>> +
>>>> +	if (WARN_ON(!client->file_ref_count))
>>>> +		goto out_unlock;
>>>> +
>>>> +	if (--client->file_ref_count)
>>>> +		goto out_unlock;
>>>> +
>>>> +	mutex_lock(&dev->filelist_mutex);
>>>> +	list_del(&client->file->lhead);
>>>> +	mutex_unlock(&dev->filelist_mutex);
>>>> +
>>>> +	drm_file_free(client->file);
>>>> +	client->file = NULL;
>>>> +	drm_dev_put(dev);
>>>> +	module_put(dev->driver->fops->owner);
>>>> +out_unlock:
>>>> +	mutex_unlock(&client->lock);
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_put_file);
>>>> +
>>>> +static struct drm_pending_event *
>>>> +drm_client_read_get_pending_event(struct drm_device *dev, struct drm_file *file)
>>>> +{
>>>> +	struct drm_pending_event *e = NULL;
>>>> +	int ret;
>>>> +
>>>> +	ret = mutex_lock_interruptible(&file->event_read_lock);
>>>> +	if (ret)
>>>> +		return ERR_PTR(ret);
>>>> +
>>>> +	spin_lock_irq(&dev->event_lock);
>>>> +	if (!list_empty(&file->event_list)) {
>>>> +		e = list_first_entry(&file->event_list,
>>>> +				     struct drm_pending_event, link);
>>>> +		file->event_space += e->event->length;
>>>> +		list_del(&e->link);
>>>> +	}
>>>> +	spin_unlock_irq(&dev->event_lock);
>>>> +
>>>> +	mutex_unlock(&file->event_read_lock);
>>>> +
>>>> +	return e;
>>>> +}
>>>> +
>>>> +struct drm_event *
>>>> +drm_client_read_event(struct drm_client_dev *client, bool block)
>>>> +{
>>>> +	struct drm_file *file = client->file;
>>>> +	struct drm_device *dev = client->dev;
>>>> +	struct drm_pending_event *e;
>>>> +	struct drm_event *event;
>>>> +	int ret;
>>>> +
>>>> +	/* Allocate so it fits all events, there's a sanity check later */
>>>> +	event = kzalloc(128, GFP_KERNEL);
>>>> +	if (!event)
>>>> +		return ERR_PTR(-ENOMEM);
>>>> +
>>>> +	e = drm_client_read_get_pending_event(dev, file);
>>>> +	if (IS_ERR(e)) {
>>>> +		ret = PTR_ERR(e);
>>>> +		goto err_free;
>>>> +	}
>>>> +
>>>> +	if (!e && !block) {
>>>> +		ret = 0;
>>>> +		goto err_free;
>>>> +	}
>>>> +
>>>> +	ret = wait_event_interruptible_timeout(file->event_wait,
>>>> +					       !list_empty(&file->event_list),
>>>> +					       5 * HZ);
>>>> +	if (!ret)
>>>> +		ret = -ETIMEDOUT;
>>>> +	if (ret < 0)
>>>> +		goto err_free;
>>>> +
>>>> +	e = drm_client_read_get_pending_event(dev, file);
>>>> +	if (IS_ERR_OR_NULL(e)) {
>>>> +		ret = PTR_ERR_OR_ZERO(e);
>>>> +		goto err_free;
>>>> +	}
>>>> +
>>>> +	if (WARN_ON(e->event->length > 128)) {
>>>> +		/* Increase buffer if this happens */
>>>> +		ret = -ENOMEM;
>>>> +		goto err_free;
>>>> +	}
>>>> +
>>>> +	memcpy(event, e->event, e->event->length);
>>>> +	kfree(e);
>>>> +
>>>> +	return event;
>>>> +
>>>> +err_free:
>>>> +	kfree(event);
>>>> +
>>>> +	return ret ? ERR_PTR(ret) : NULL;
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_read_event);
>>>> +
>>>> +static void drm_client_connector_free(struct drm_client_connector *connector)
>>>> +{
>>>> +	if (!connector)
>>>> +		return;
>>>> +	kfree(connector->modes);
>>>> +	kfree(connector);
>>>> +}
>>>> +
>>>> +static struct drm_client_connector *
>>>> +drm_client_get_connector(struct drm_client_dev *client, unsigned int id)
>>>> +{
>>>> +	struct drm_mode_get_connector req = {
>>>> +		.connector_id = id,
>>>> +	};
>>>> +	struct drm_client_connector *connector;
>>>> +	struct drm_mode_modeinfo *modes = NULL;
>>>> +	struct drm_device *dev = client->dev;
>>>> +	struct drm_connector *conn;
>>>> +	bool non_desktop;
>>>> +	int ret;
>>>> +
>>>> +	connector = kzalloc(sizeof(*connector), GFP_KERNEL);
>>>> +	if (!connector)
>>>> +		return ERR_PTR(-ENOMEM);
>>>> +
>>>> +	ret = drm_mode_getconnector(dev, &req, client->file, false);
>>>> +	if (ret)
>>>> +		goto err_free;
>>>> +
>>>> +	connector->conn_id = id;
>>>> +	connector->status = req.connection;
>>>> +
>>>> +	conn = drm_connector_lookup(dev, client->file, id);
>>>> +	if (!conn) {
>>>> +		ret = -ENOENT;
>>>> +		goto err_free;
>>>> +	}
>>>> +
>>>> +	non_desktop = conn->display_info.non_desktop;
>>>> +
>>>> +	connector->has_tile = conn->has_tile;
>>>> +	connector->tile_h_loc = conn->tile_h_loc;
>>>> +	connector->tile_v_loc = conn->tile_v_loc;
>>>> +	if (conn->tile_group)
>>>> +		connector->tile_group = conn->tile_group->id;
>>>> +
>>>> +	drm_connector_put(conn);
>>>> +
>>>> +	if (non_desktop) {
>>>> +		kfree(connector);
>>>> +		return NULL;
>>>> +	}
>>>> +
>>>> +	if (!req.count_modes)
>>>> +		return connector;
>>>> +
>>>> +	modes = kcalloc(req.count_modes, sizeof(*modes), GFP_KERNEL);
>>>> +	if (!modes) {
>>>> +		ret = -ENOMEM;
>>>> +		goto err_free;
>>>> +	}
>>>> +
>>>> +	connector->modes = modes;
>>>> +	connector->num_modes = req.count_modes;
>>>> +
>>>> +	req.count_props = 0;
>>>> +	req.count_encoders = 0;
>>>> +	req.modes_ptr = (unsigned long)modes;
>>>> +
>>>> +	ret = drm_mode_getconnector(dev, &req, client->file, false);
>>>> +	if (ret)
>>>> +		goto err_free;
>>>> +
>>>> +	return connector;
>>>> +
>>>> +err_free:
>>>> +	kfree(modes);
>>>> +	kfree(connector);
>>>> +
>>>> +	return ERR_PTR(ret);
>>>> +}
>>>> +
>>>> +static int drm_client_get_connectors(struct drm_client_dev *client,
>>>> +				     struct drm_client_connector ***connectors)
>>>> +{
>>>> +	struct drm_mode_card_res card_res = {};
>>>> +	struct drm_device *dev = client->dev;
>>>> +	int ret, num_connectors;
>>>> +	u32 *connector_ids;
>>>> +	unsigned int i;
>>>> +
>>>> +	ret = drm_mode_getresources(dev, &card_res, client->file, false);
>>>> +	if (ret)
>>>> +		return ret;
>>>> +	if (!card_res.count_connectors)
>>>> +		return 0;
>>>> +
>>>> +	num_connectors = card_res.count_connectors;
>>>> +	connector_ids = kcalloc(num_connectors,
>>>> +				sizeof(*connector_ids), GFP_KERNEL);
>>>> +	if (!connector_ids)
>>>> +		return -ENOMEM;
>>>> +
>>>> +	card_res.count_fbs = 0;
>>>> +	card_res.count_crtcs = 0;
>>>> +	card_res.count_encoders = 0;
>>>> +	card_res.connector_id_ptr = (unsigned long)connector_ids;
>>>> +
>>>> +	ret = drm_mode_getresources(dev, &card_res, client->file, false);
>>>> +	if (ret)
>>>> +		goto err_free;
>>>> +
>>>> +	*connectors = kcalloc(num_connectors, sizeof(**connectors), GFP_KERNEL);
>>>> +	if (!(*connectors)) {
>>>> +		ret = -ENOMEM;
>>>> +		goto err_free;
>>>> +	}
>>>> +
>>>> +	for (i = 0; i < num_connectors; i++) {
>>>> +		struct drm_client_connector *connector;
>>>> +
>>>> +		connector = drm_client_get_connector(client, connector_ids[i]);
>>>> +		if (IS_ERR(connector)) {
>>>> +			ret = PTR_ERR(connector);
>>>> +			goto err_free;
>>>> +		}
>>>> +		if (connector)
>>>> +			(*connectors)[i] = connector;
>>>> +		else
>>>> +			num_connectors--;
>>>> +	}
>>>> +
>>>> +	if (!num_connectors) {
>>>> +		ret = 0;
>>>> +		goto err_free;
>>>> +	}
>>>> +
>>>> +	return num_connectors;
>>>> +
>>>> +err_free:
>>>> +	if (connectors)
>>>> +		for (i = 0; i < num_connectors; i++)
>>>> +			drm_client_connector_free((*connectors)[i]);
>>>> +
>>>> +	kfree(connectors);
>>>> +	kfree(connector_ids);
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +
>>>> +static bool
>>>> +drm_client_connector_is_enabled(struct drm_client_connector *connector,
>>>> +				bool strict)
>>>> +{
>>>> +	if (strict)
>>>> +		return connector->status == connector_status_connected;
>>>> +	else
>>>> +		return connector->status != connector_status_disconnected;
>>>> +}
>>>> +
>>>> +struct drm_mode_modeinfo *
>>>> +drm_client_display_first_mode(struct drm_client_display *display)
>>>> +{
>>>> +	if (!display->num_modes)
>>>> +		return NULL;
>>>> +	return display->modes;
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_display_first_mode);
>>>> +
>>>> +struct drm_mode_modeinfo *
>>>> +drm_client_display_next_mode(struct drm_client_display *display,
>>>> +			     struct drm_mode_modeinfo *mode)
>>>> +{
>>>> +	struct drm_mode_modeinfo *modes = display->modes;
>>>> +
>>>> +	if (++mode < &modes[display->num_modes])
>>>> +		return mode;
>>>> +
>>>> +	return NULL;
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_display_next_mode);
>>>> +
>>>> +static void
>>>> +drm_client_display_fill_tile_modes(struct drm_client_display *display,
>>>> +				   struct drm_mode_modeinfo *tile_modes)
>>>> +{
>>>> +	unsigned int i, j, num_modes = display->connectors[0]->num_modes;
>>>> +	struct drm_mode_modeinfo *tile_mode, *conn_mode;
>>>> +
>>>> +	if (!num_modes) {
>>>> +		kfree(tile_modes);
>>>> +		kfree(display->modes);
>>>> +		display->modes = NULL;
>>>> +		display->num_modes = 0;
>>>> +		return;
>>>> +	}
>>>> +
>>>> +	for (i = 0; i < num_modes; i++) {
>>>> +		tile_mode = &tile_modes[i];
>>>> +
>>>> +		conn_mode = &display->connectors[0]->modes[i];
>>>> +		tile_mode->clock = conn_mode->clock;
>>>> +		tile_mode->vscan = conn_mode->vscan;
>>>> +		tile_mode->vrefresh = conn_mode->vrefresh;
>>>> +		tile_mode->flags = conn_mode->flags;
>>>> +		tile_mode->type = conn_mode->type;
>>>> +
>>>> +		for (j = 0; j < display->num_connectors; j++) {
>>>> +			conn_mode = &display->connectors[j]->modes[i];
>>>> +
>>>> +			if (!display->connectors[j]->tile_h_loc) {
>>>> +				tile_mode->hdisplay += conn_mode->hdisplay;
>>>> +				tile_mode->hsync_start += conn_mode->hsync_start;
>>>> +				tile_mode->hsync_end += conn_mode->hsync_end;
>>>> +				tile_mode->htotal += conn_mode->htotal;
>>>> +			}
>>>> +
>>>> +			if (!display->connectors[j]->tile_v_loc) {
>>>> +				tile_mode->vdisplay += conn_mode->vdisplay;
>>>> +				tile_mode->vsync_start += conn_mode->vsync_start;
>>>> +				tile_mode->vsync_end += conn_mode->vsync_end;
>>>> +				tile_mode->vtotal += conn_mode->vtotal;
>>>> +			}
>>>> +		}
>>>> +	}
>>>> +
>>>> +	kfree(display->modes);
>>>> +	display->modes = tile_modes;
>>>> +	display->num_modes = num_modes;
>>>> +}
>>>> +
>>>> +/**
>>>> + * drm_client_display_update_modes - Fetch display modes
>>>> + * @display: Client display
>>>> + * @mode_changed: Optional pointer to boolen which return whether the modes
>>>> + *                have changed or not.
>>>> + *
>>>> + * This function can be used in the client hotplug callback to check if the
>>>> + * video modes have changed and get them up-to-date.
>>>> + *
>>>> + * Returns:
>>>> + * Number of modes on success, negative error code on failure.
>>>> + */
>>>> +int drm_client_display_update_modes(struct drm_client_display *display,
>>>> +				    bool *mode_changed)
>>>> +{
>>>> +	unsigned int num_connectors = display->num_connectors;
>>>> +	struct drm_client_dev *client = display->client;
>>>> +	struct drm_mode_modeinfo *display_tile_modes;
>>>> +	struct drm_client_connector **connectors;
>>>> +	unsigned int i, num_modes = 0;
>>>> +	bool dummy_changed = false;
>>>> +	int ret;
>>>> +
>>>> +	if (mode_changed)
>>>> +		*mode_changed = false;
>>>> +	else
>>>> +		mode_changed = &dummy_changed;
>>>> +
>>>> +	if (display->cloned)
>>>> +		return 2;
>>>> +
>>>> +	ret = drm_client_get_file(client);
>>>> +	if (ret)
>>>> +		return ret;
>>>> +
>>>> +	connectors = kcalloc(num_connectors, sizeof(*connectors), GFP_KERNEL);
>>>> +	if (!connectors) {
>>>> +		ret = -ENOMEM;
>>>> +		goto out_put_file;
>>>> +	}
>>>> +
>>>> +	/* Get a new set for comparison */
>>>> +	for (i = 0; i < num_connectors; i++) {
>>>> +		connectors[i] = drm_client_get_connector(client, display->connectors[i]->conn_id);
>>>> +		if (IS_ERR_OR_NULL(connectors[i])) {
>>>> +			ret = PTR_ERR_OR_ZERO(connectors[i]);
>>>> +			if (!ret)
>>>> +				ret = -ENOENT;
>>>> +			goto out_cleanup;
>>>> +		}
>>>> +	}
>>>> +
>>>> +	/* All connectors should have the same number of modes */
>>>> +	num_modes = connectors[0]->num_modes;
>>>> +	for (i = 0; i < num_connectors; i++) {
>>>> +		if (num_modes != connectors[i]->num_modes) {
>>>> +			ret = -EINVAL;
>>>> +			goto out_cleanup;
>>>> +		}
>>>> +	}
>>>> +
>>>> +	if (num_connectors > 1) {
>>>> +		display_tile_modes = kcalloc(num_modes, sizeof(*display_tile_modes), GFP_KERNEL);
>>>> +		if (!display_tile_modes) {
>>>> +			ret = -ENOMEM;
>>>> +			goto out_cleanup;
>>>> +		}
>>>> +	}
>>>> +
>>>> +	mutex_lock(&display->modes_lock);
>>>> +
>>>> +	for (i = 0; i < num_connectors; i++) {
>>>> +		display->connectors[i]->status = connectors[i]->status;
>>>> +		if (display->connectors[i]->num_modes != connectors[i]->num_modes) {
>>>> +			display->connectors[i]->num_modes = connectors[i]->num_modes;
>>>> +			kfree(display->connectors[i]->modes);
>>>> +			display->connectors[i]->modes = connectors[i]->modes;
>>>> +			connectors[i]->modes = NULL;
>>>> +			*mode_changed = true;
>>>> +		}
>>>> +	}
>>>> +
>>>> +	if (num_connectors > 1)
>>>> +		drm_client_display_fill_tile_modes(display, display_tile_modes);
>>>> +	else
>>>> +		display->modes = display->connectors[0]->modes;
>>>> +
>>>> +	mutex_unlock(&display->modes_lock);
>>>> +
>>>> +out_cleanup:
>>>> +	for (i = 0; i < num_connectors; i++)
>>>> +		drm_client_connector_free(connectors[i]);
>>>> +	kfree(connectors);
>>>> +out_put_file:
>>>> +	drm_client_put_file(client);
>>>> +
>>>> +	return ret ? ret : num_modes;
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_display_update_modes);
>>>> +
>>>> +void drm_client_display_free(struct drm_client_display *display)
>>>> +{
>>>> +	unsigned int i;
>>>> +
>>>> +	if (!display)
>>>> +		return;
>>>> +
>>>> +	/* tile modes? */
>>>> +	if (display->modes != display->connectors[0]->modes)
>>>> +		kfree(display->modes);
>>>> +
>>>> +	for (i = 0; i < display->num_connectors; i++)
>>>> +		drm_client_connector_free(display->connectors[i]);
>>>> +
>>>> +	kfree(display->connectors);
>>>> +	mutex_destroy(&display->modes_lock);
>>>> +	kfree(display);
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_display_free);
>>>> +
>>>> +static struct drm_client_display *
>>>> +drm_client_display_alloc(struct drm_client_dev *client,
>>>> +			 unsigned int num_connectors)
>>>> +{
>>>> +	struct drm_client_display *display;
>>>> +	struct drm_client_connector **connectors;
>>>> +
>>>> +	display = kzalloc(sizeof(*display), GFP_KERNEL);
>>>> +	connectors = kcalloc(num_connectors, sizeof(*connectors), GFP_KERNEL);
>>>> +	if (!display || !connectors) {
>>>> +		kfree(display);
>>>> +		kfree(connectors);
>>>> +		return NULL;
>>>> +	}
>>>> +
>>>> +	mutex_init(&display->modes_lock);
>>>> +	display->client = client;
>>>> +	display->connectors = connectors;
>>>> +	display->num_connectors = num_connectors;
>>>> +
>>>> +	return display;
>>>> +}
>>>> +
>>>> +/* Logic is from drm_fb_helper */
>>>> +static struct drm_client_display *
>>>> +drm_client_connector_pick_cloned(struct drm_client_dev *client,
>>>> +				 struct drm_client_connector **connectors,
>>>> +				 unsigned int num_connectors)
>>>> +{
>>>> +	struct drm_mode_modeinfo modes[2], udmt_mode, *mode, *tmp;
>>>> +	struct drm_display_mode *dmt_display_mode = NULL;
>>>> +	unsigned int i, j, conns[2], num_conns = 0;
>>>> +	struct drm_client_connector *connector;
>>>> +	struct drm_device *dev = client->dev;
>>>> +	struct drm_client_display *display;
>>>> +
>>>> +	/* only contemplate cloning in the single crtc case */
>>>> +	if (dev->mode_config.num_crtc > 1)
>>>> +		return NULL;
>>>> +retry:
>>>> +	for (i = 0; i < num_connectors; i++) {
>>>> +		connector = connectors[i];
>>>> +		if (!connector || connector->has_tile || !connector->num_modes)
>>>> +			continue;
>>>> +
>>>> +		for (j = 0; j < connector->num_modes; j++) {
>>>> +			mode = &connector->modes[j];
>>>> +			if (dmt_display_mode) {
>>>> +				if (drm_umode_equal(&udmt_mode, mode)) {
>>>> +					conns[num_conns] = i;
>>>> +					modes[num_conns++] = *mode;
>>>> +					break;
>>>> +				}
>>>> +			} else {
>>>> +				if (mode->type & DRM_MODE_TYPE_USERDEF) {
>>>> +					conns[num_conns] = i;
>>>> +					modes[num_conns++] = *mode;
>>>> +					break;
>>>> +				}
>>>> +			}
>>>> +		}
>>>> +		if (num_conns == 2)
>>>> +			break;
>>>> +	}
>>>> +
>>>> +	if (num_conns == 2)
>>>> +		goto found;
>>>> +
>>>> +	if (dmt_display_mode)
>>>> +		return NULL;
>>>> +
>>>> +	dmt_display_mode = drm_mode_find_dmt(dev, 1024, 768, 60, false);
>>>> +	drm_mode_convert_to_umode(&udmt_mode, dmt_display_mode);
>>>> +	drm_mode_destroy(dev, dmt_display_mode);
>>>> +
>>>> +	goto retry;
>>>> +
>>>> +found:
>>>> +	tmp = kcalloc(2, sizeof(*tmp), GFP_KERNEL);
>>>> +	if (!tmp)
>>>> +		return ERR_PTR(-ENOMEM);
>>>> +
>>>> +	display = drm_client_display_alloc(client, 2);
>>>> +	if (!display) {
>>>> +		kfree(tmp);
>>>> +		return ERR_PTR(-ENOMEM);
>>>> +	}
>>>> +
>>>> +	for (i = 0; i < 2; i++) {
>>>> +		connector = connectors[conns[i]];
>>>> +		display->connectors[i] = connector;
>>>> +		connectors[conns[i]] = NULL;
>>>> +		kfree(connector->modes);
>>>> +		tmp[i] = modes[i];
>>>> +		connector->modes = &tmp[i];
>>>> +		connector->num_modes = 1;
>>>> +	}
>>>> +
>>>> +	display->cloned = true;
>>>> +	display->modes = &tmp[0];
>>>> +	display->num_modes = 1;
>>>> +
>>>> +	return display;
>>>> +}
>>>> +
>>>> +static struct drm_client_display *
>>>> +drm_client_connector_pick_tile(struct drm_client_dev *client,
>>>> +			       struct drm_client_connector **connectors,
>>>> +			       unsigned int num_connectors)
>>>> +{
>>>> +	unsigned int i, num_conns, num_modes, tile_group = 0;
>>>> +	struct drm_mode_modeinfo *tile_modes = NULL;
>>>> +	struct drm_client_connector *connector;
>>>> +	struct drm_client_display *display;
>>>> +	u16 conns[32];
>>>> +
>>>> +	for (i = 0; i < num_connectors; i++) {
>>>> +		connector = connectors[i];
>>>> +		if (!connector || !connector->tile_group)
>>>> +			continue;
>>>> +
>>>> +		if (!tile_group) {
>>>> +			tile_group = connector->tile_group;
>>>> +			num_modes = connector->num_modes;
>>>> +		}
>>>> +
>>>> +		if (connector->tile_group != tile_group)
>>>> +			continue;
>>>> +
>>>> +		if (num_modes != connector->num_modes) {
>>>> +			DRM_ERROR("Tile connectors must have the same number of modes\n");
>>>> +			return ERR_PTR(-EINVAL);
>>>> +		}
>>>> +
>>>> +		conns[num_conns++] = i;
>>>> +		if (WARN_ON(num_conns == 33))
>>>> +			return ERR_PTR(-EINVAL);
>>>> +	}
>>>> +
>>>> +	if (!num_conns)
>>>> +		return NULL;
>>>> +
>>>> +	if (num_modes) {
>>>> +		tile_modes = kcalloc(num_modes, sizeof(*tile_modes), GFP_KERNEL);
>>>> +		if (!tile_modes)
>>>> +			return ERR_PTR(-ENOMEM);
>>>> +	}
>>>> +
>>>> +	display = drm_client_display_alloc(client, num_conns);
>>>> +	if (!display) {
>>>> +		kfree(tile_modes);
>>>> +		return ERR_PTR(-ENOMEM);
>>>> +	}
>>>> +
>>>> +	if (num_modes)
>>>> +		drm_client_display_fill_tile_modes(display, tile_modes);
>>>> +
>>>> +	return display;
>>>> +}
>>>> +
>>>> +static struct drm_client_display *
>>>> +drm_client_connector_pick_not_tile(struct drm_client_dev *client,
>>>> +				   struct drm_client_connector **connectors,
>>>> +				   unsigned int num_connectors)
>>>> +{
>>>> +	struct drm_client_display *display;
>>>> +	unsigned int i;
>>>> +
>>>> +	for (i = 0; i < num_connectors; i++) {
>>>> +		if (!connectors[i] || connectors[i]->has_tile)
>>>> +			continue;
>>>> +		break;
>>>> +	}
>>>> +
>>>> +	if (i == num_connectors)
>>>> +		return NULL;
>>>> +
>>>> +	display = drm_client_display_alloc(client, 1);
>>>> +	if (!display)
>>>> +		return ERR_PTR(-ENOMEM);
>>>> +
>>>> +	display->connectors[0] = connectors[i];
>>>> +	connectors[i] = NULL;
>>>> +	display->modes = display->connectors[0]->modes;
>>>> +	display->num_modes = display->connectors[0]->num_modes;
>>>> +
>>>> +	return display;
>>>> +}
>>>> +
>>>> +/* Get connectors and bundle them up into displays */
>>>> +static int drm_client_get_displays(struct drm_client_dev *client,
>>>> +				   struct drm_client_display ***displays)
>>>> +{
>>>> +	int ret, num_connectors, num_displays = 0;
>>>> +	struct drm_client_connector **connectors;
>>>> +	struct drm_client_display *display;
>>>> +	unsigned int i;
>>>> +
>>>> +	ret = drm_client_get_file(client);
>>>> +	if (ret)
>>>> +		return ret;
>>>> +
>>>> +	num_connectors = drm_client_get_connectors(client, &connectors);
>>>> +	if (num_connectors <= 0) {
>>>> +		ret = num_connectors;
>>>> +		goto err_put_file;
>>>> +	}
>>>> +
>>>> +	*displays = kcalloc(num_connectors, sizeof(*displays), GFP_KERNEL);
>>>> +	if (!(*displays)) {
>>>> +		ret = -ENOMEM;
>>>> +		goto err_free;
>>>> +	}
>>>> +
>>>> +	display = drm_client_connector_pick_cloned(client, connectors,
>>>> +						   num_connectors);
>>>> +	if (IS_ERR(display)) {
>>>> +		ret = PTR_ERR(display);
>>>> +		goto err_free;
>>>> +	}
>>>> +	if (display)
>>>> +		(*displays)[num_displays++] = display;
>>>> +
>>>> +	for (i = 0; i < num_connectors; i++) {
>>>> +		display = drm_client_connector_pick_tile(client, connectors,
>>>> +							 num_connectors);
>>>> +		if (IS_ERR(display)) {
>>>> +			ret = PTR_ERR(display);
>>>> +			goto err_free;
>>>> +		}
>>>> +		if (!display)
>>>> +			break;
>>>> +		(*displays)[num_displays++] = display;
>>>> +	}
>>>> +
>>>> +	for (i = 0; i < num_connectors; i++) {
>>>> +		display = drm_client_connector_pick_not_tile(client, connectors,
>>>> +							     num_connectors);
>>>> +		if (IS_ERR(display)) {
>>>> +			ret = PTR_ERR(display);
>>>> +			goto err_free;
>>>> +		}
>>>> +		if (!display)
>>>> +			break;
>>>> +		(*displays)[num_displays++] = display;
>>>> +	}
>>>> +
>>>> +	for (i = 0; i < num_connectors; i++) {
>>>> +		if (connectors[i]) {
>>>> +			DRM_INFO("Connector %u fell through the cracks.\n",
>>>> +				 connectors[i]->conn_id);
>>>> +			drm_client_connector_free(connectors[i]);
>>>> +		}
>>>> +	}
>>>> +
>>>> +	drm_client_put_file(client);
>>>> +	kfree(connectors);
>>>> +
>>>> +	return num_displays;
>>>> +
>>>> +err_free:
>>>> +	for (i = 0; i < num_displays; i++)
>>>> +		drm_client_display_free((*displays)[i]);
>>>> +	kfree(*displays);
>>>> +	*displays = NULL;
>>>> +	for (i = 0; i < num_connectors; i++)
>>>> +		drm_client_connector_free(connectors[i]);
>>>> +	kfree(connectors);
>>>> +err_put_file:
>>>> +	drm_client_put_file(client);
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +
>>>> +static bool
>>>> +drm_client_display_is_enabled(struct drm_client_display *display, bool strict)
>>>> +{
>>>> +	unsigned int i;
>>>> +
>>>> +	if (!display->num_modes)
>>>> +		return false;
>>>> +
>>>> +	for (i = 0; i < display->num_connectors; i++)
>>>> +		if (!drm_client_connector_is_enabled(display->connectors[i], strict))
>>>> +			return false;
>>>> +
>>>> +	return true;
>>>> +}
>>>> +
>>>> +/**
>>>> + * drm_client_display_get_first_enabled - Get first enabled display
>>>> + * @client: DRM client
>>>> + * @strict: If true the connector(s) have to be connected, if false they can
>>>> + *          also have unknown status.
>>>> + *
>>>> + * This function gets all connectors and bundles them into displays
>>>> + * (tiled/cloned). It then picks the first one with connectors that is enabled
>>>> + * according to @strict.
>>>> + *
>>>> + * Returns:
>>>> + * Pointer to a client display if such a display was found, NULL if not found
>>>> + * or an error pointer on failure.
>>>> + */
>>>> +struct drm_client_display *
>>>> +drm_client_display_get_first_enabled(struct drm_client_dev *client, bool strict)
>>>> +{
>>>> +	struct drm_client_display **displays, *display = NULL;
>>>> +	int num_displays;
>>>> +	unsigned int i;
>>>> +
>>>> +	num_displays = drm_client_get_displays(client, &displays);
>>>> +	if (num_displays < 0)
>>>> +		return ERR_PTR(num_displays);
>>>> +	if (!num_displays)
>>>> +		return NULL;
>>>> +
>>>> +	for (i = 0; i < num_displays; i++) {
>>>> +		if (!display &&
>>>> +		    drm_client_display_is_enabled(displays[i], strict)) {
>>>> +			display = displays[i];
>>>> +			continue;
>>>> +		}
>>>> +		drm_client_display_free(displays[i]);
>>>> +	}
>>>> +
>>>> +	kfree(displays);
>>>> +
>>>> +	return display;
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_display_get_first_enabled);
>>>> +
>>>> +unsigned int
>>>> +drm_client_display_preferred_depth(struct drm_client_display *display)
>>>> +{
>>>> +	struct drm_connector *conn;
>>>> +	unsigned int ret;
>>>> +
>>>> +	conn = drm_connector_lookup(display->client->dev, NULL,
>>>> +				    display->connectors[0]->conn_id);
>>>> +	if (!conn)
>>>> +		return 0;
>>>> +
>>>> +	if (conn->cmdline_mode.bpp_specified)
>>>> +		ret = conn->cmdline_mode.bpp;
>>>> +	else
>>>> +		ret = display->client->dev->mode_config.preferred_depth;
>>>> +
>>>> +	drm_connector_put(conn);
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_display_preferred_depth);
>>>> +
>>>> +int drm_client_display_dpms(struct drm_client_display *display, int mode)
>>>> +{
>>>> +	struct drm_mode_obj_set_property prop;
>>>> +
>>>> +	prop.value = mode;
>>>> +	prop.prop_id = display->client->dev->mode_config.dpms_property->base.id;
>>>> +	prop.obj_id = display->connectors[0]->conn_id;
>>>> +	prop.obj_type = DRM_MODE_OBJECT_CONNECTOR;
>>>> +
>>>> +	return drm_mode_obj_set_property(display->client->dev, &prop,
>>>> +					 display->client->file);
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_display_dpms);
>>>> +
>>>> +int drm_client_display_wait_vblank(struct drm_client_display *display)
>>>> +{
>>>> +	struct drm_crtc *crtc;
>>>> +	union drm_wait_vblank vblank_req = {
>>>> +		.request = {
>>>> +			.type = _DRM_VBLANK_RELATIVE,
>>>> +			.sequence = 1,
>>>> +		},
>>>> +	};
>>>> +
>>>> +	crtc = drm_crtc_find(display->client->dev, display->client->file,
>>>> +			     display->connectors[0]->crtc_id);
>>>> +	if (!crtc)
>>>> +		return -ENOENT;
>>>> +
>>>> +	vblank_req.request.type |= drm_crtc_index(crtc) << _DRM_VBLANK_HIGH_CRTC_SHIFT;
>>>> +
>>>> +	return drm_wait_vblank(display->client->dev, &vblank_req,
>>>> +			       display->client->file);
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_display_wait_vblank);
>>>> +
>>>> +static int drm_client_get_crtc_index(struct drm_client_dev *client, u32 id)
>>>> +{
>>>> +	int i;
>>>> +
>>>> +	for (i = 0; i < client->num_crtcs; i++)
>>>> +		if (client->crtcs[i] == id)
>>>> +			return i;
>>>> +
>>>> +	return -ENOENT;
>>>> +}
>>>> +
>>>> +static int drm_client_display_find_crtcs(struct drm_client_display *display)
>>>> +{
>>>> +	struct drm_client_dev *client = display->client;
>>>> +	struct drm_device *dev = client->dev;
>>>> +	struct drm_file *file = client->file;
>>>> +	u32 encoder_ids[DRM_CONNECTOR_MAX_ENCODER];
>>>> +	unsigned int i, j, available_crtcs = ~0;
>>>> +	struct drm_mode_get_connector conn_req;
>>>> +	struct drm_mode_get_encoder enc_req;
>>>> +	int ret;
>>>> +
>>>> +	/* Already done? */
>>>> +	if (display->connectors[0]->crtc_id)
>>>> +		return 0;
>>>> +
>>>> +	for (i = 0; i < display->num_connectors; i++) {
>>>> +		u32 active_crtcs = 0, crtcs_for_connector = 0;
>>>> +		int crtc_idx;
>>>> +
>>>> +		memset(&conn_req, 0, sizeof(conn_req));
>>>> +		conn_req.connector_id = display->connectors[i]->conn_id;
>>>> +		conn_req.encoders_ptr = (unsigned long)(encoder_ids);
>>>> +		conn_req.count_encoders = DRM_CONNECTOR_MAX_ENCODER;
>>>> +		ret = drm_mode_getconnector(dev, &conn_req, file, false);
>>>> +		if (ret)
>>>> +			return ret;
>>>> +
>>>> +		if (conn_req.encoder_id) {
>>>> +			memset(&enc_req, 0, sizeof(enc_req));
>>>> +			enc_req.encoder_id = conn_req.encoder_id;
>>>> +			ret = drm_mode_getencoder(dev, &enc_req, file);
>>>> +			if (ret)
>>>> +				return ret;
>>>> +			crtcs_for_connector |= enc_req.possible_crtcs;
>>>> +			if (crtcs_for_connector & available_crtcs)
>>>> +				goto found;
>>>> +		}
>>>> +
>>>> +		for (j = 0; j < conn_req.count_encoders; j++) {
>>>> +			memset(&enc_req, 0, sizeof(enc_req));
>>>> +			enc_req.encoder_id = encoder_ids[j];
>>>> +			ret = drm_mode_getencoder(dev, &enc_req, file);
>>>> +			if (ret)
>>>> +				return ret;
>>>> +
>>>> +			crtcs_for_connector |= enc_req.possible_crtcs;
>>>> +
>>>> +			if (enc_req.crtc_id) {
>>>> +				crtc_idx = drm_client_get_crtc_index(client, enc_req.crtc_id);
>>>> +				if (crtc_idx >= 0)
>>>> +					active_crtcs |= 1 << crtc_idx;
>>>> +			}
>>>> +		}
>>>> +
>>>> +found:
>>>> +		crtcs_for_connector &= available_crtcs;
>>>> +		active_crtcs &= available_crtcs;
>>>> +
>>>> +		if (!crtcs_for_connector)
>>>> +			return -ENOENT;
>>>> +
>>>> +		if (active_crtcs)
>>>> +			crtc_idx = ffs(active_crtcs) - 1;
>>>> +		else
>>>> +			crtc_idx = ffs(crtcs_for_connector) - 1;
>>>> +
>>>> +		if (crtc_idx >= client->num_crtcs)
>>>> +			return -EINVAL;
>>>> +
>>>> +		display->connectors[i]->crtc_id = client->crtcs[crtc_idx];
>>>> +		available_crtcs &= ~BIT(crtc_idx);
>>>> +	}
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +/**
>>>> + * drm_client_display_commit_mode - Commit a mode to the crtc(s)
>>>> + * @display: Client display
>>>> + * @fb_id: Framebuffer id
>>>> + * @mode: Video mode
>>>> + *
>>>> + * Returns:
>>>> + * Zero on success, negative error code on failure.
>>>> + */
>>>> +int drm_client_display_commit_mode(struct drm_client_display *display,
>>>> +				   u32 fb_id, struct drm_mode_modeinfo *mode)
>>>> +{
>>>> +	struct drm_client_dev *client = display->client;
>>>> +	struct drm_device *dev = client->dev;
>>>> +	unsigned int num_crtcs = client->num_crtcs;
>>>> +	struct drm_file *file = client->file;
>>>> +	unsigned int *xoffsets = NULL, *yoffsets = NULL;
>>>> +	struct drm_mode_crtc *crtc_reqs, *req;
>>>> +	u32 cloned_conn_ids[2];
>>>> +	unsigned int i;
>>>> +	int idx, ret;
>>>> +
>>>> +	ret = drm_client_display_find_crtcs(display);
>>>> +	if (ret)
>>>> +		return ret;
>>>> +
>>>> +	crtc_reqs = kcalloc(num_crtcs, sizeof(*crtc_reqs), GFP_KERNEL);
>>>> +	if (!crtc_reqs)
>>>> +		return -ENOMEM;
>>>> +
>>>> +	for (i = 0; i < num_crtcs; i++)
>>>> +		crtc_reqs[i].crtc_id = client->crtcs[i];
>>>> +
>>>> +	if (drm_client_display_is_tiled(display)) {
>>>> +		/* TODO calculate tile crtc offsets */
>>>> +	}
>>>> +
>>>> +	for (i = 0; i < display->num_connectors; i++) {
>>>> +		idx = drm_client_get_crtc_index(client, display->connectors[i]->crtc_id);
>>>> +		if (idx < 0)
>>>> +			return -ENOENT;
>>>> +
>>>> +		req = &crtc_reqs[idx];
>>>> +
>>>> +		req->fb_id = fb_id;
>>>> +		if (xoffsets) {
>>>> +			req->x = xoffsets[i];
>>>> +			req->y = yoffsets[i];
>>>> +		}
>>>> +		req->mode_valid = 1;
>>>> +		req->mode = *mode;
>>>> +
>>>> +		if (display->cloned) {
>>>> +			cloned_conn_ids[0] = display->connectors[0]->conn_id;
>>>> +			cloned_conn_ids[1] = display->connectors[1]->conn_id;
>>>> +			req->set_connectors_ptr = (unsigned long)(cloned_conn_ids);
>>>> +			req->count_connectors = 2;
>>>> +			break;
>>>> +		}
>>>> +
>>>> +		req->set_connectors_ptr = (unsigned long)(&display->connectors[i]->conn_id);
>>>> +		req->count_connectors = 1;
>>>> +	}
>>>> +
>>>> +	for (i = 0; i < num_crtcs; i++) {
>>>> +		ret = drm_mode_setcrtc(dev, &crtc_reqs[i], file, false);
>>>> +		if (ret)
>>>> +			break;
>>>> +	}
>>>> +
>>>> +	kfree(xoffsets);
>>>> +	kfree(yoffsets);
>>>> +	kfree(crtc_reqs);
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_display_commit_mode);
>>>> +
>>>> +unsigned int drm_client_display_current_fb(struct drm_client_display *display)
>>>> +{
>>>> +	struct drm_client_dev *client = display->client;
>>>> +	int ret;
>>>> +	struct drm_mode_crtc crtc_req = {
>>>> +		.crtc_id = display->connectors[0]->crtc_id,
>>>> +	};
>>>> +
>>>> +	ret = drm_mode_getcrtc(client->dev, &crtc_req, client->file);
>>>> +	if (ret)
>>>> +		return 0;
>>>> +
>>>> +	return crtc_req.fb_id;
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_display_current_fb);
>>>> +
>>>> +int drm_client_display_flush(struct drm_client_display *display, u32 fb_id,
>>>> +			     struct drm_clip_rect *clips, unsigned int num_clips)
>>>> +{
>>>> +	struct drm_client_dev *client = display->client;
>>>> +	struct drm_mode_fb_dirty_cmd dirty_req = {
>>>> +		.fb_id = fb_id,
>>>> +		.clips_ptr = (unsigned long)clips,
>>>> +		.num_clips = num_clips,
>>>> +	};
>>>> +	int ret;
>>>> +
>>>> +	if (display->no_flushing)
>>>> +		return 0;
>>>> +
>>>> +	ret = drm_mode_dirtyfb(client->dev, &dirty_req, client->file, false);
>>>> +	if (ret == -ENOSYS) {
>>>> +		ret = 0;
>>>> +		display->no_flushing = true;
>>>> +	}
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_display_flush);
>>>> +
>>>> +int drm_client_display_page_flip(struct drm_client_display *display, u32 fb_id,
>>>> +				 bool event)
>>>> +{
>>>> +	struct drm_client_dev *client = display->client;
>>>> +	struct drm_mode_crtc_page_flip_target page_flip_req = {
>>>> +		.crtc_id = display->connectors[0]->crtc_id,
>>>> +		.fb_id = fb_id,
>>>> +	};
>>>> +
>>>> +	if (event)
>>>> +		page_flip_req.flags = DRM_MODE_PAGE_FLIP_EVENT;
>>>> +
>>>> +	return drm_mode_page_flip(client->dev, &page_flip_req, client->file);
>>>> +	/*
>>>> +	 * TODO:
>>>> +	 * Where do we flush on page flip? Should the driver handle that?
>>>> +	 */
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_display_page_flip);
>>>> +
>>>> +/**
>>>> + * drm_client_framebuffer_create - Create a client framebuffer
>>>> + * @client: DRM client
>>>> + * @mode: Display mode to create a buffer for
>>>> + * @format: Buffer format
>>>> + *
>>>> + * This function creates a &drm_client_buffer which consists of a
>>>> + * &drm_framebuffer backed by a dumb buffer. The dumb buffer is &dma_buf
>>>> + * exported to aquire a virtual address which is stored in
>>>> + * &drm_client_buffer->vaddr.
>>>> + * Call drm_client_framebuffer_delete() to free the buffer.
>>>> + *
>>>> + * Returns:
>>>> + * Pointer to a client buffer or an error pointer on failure.
>>>> + */
>>>> +struct drm_client_buffer *
>>>> +drm_client_framebuffer_create(struct drm_client_dev *client,
>>>> +			      struct drm_mode_modeinfo *mode, u32 format)
>>>> +{
>>>> +	struct drm_client_buffer *buffer;
>>>> +	int ret;
>>>> +
>>>> +	buffer = drm_client_buffer_create(client, mode->hdisplay,
>>>> +					  mode->vdisplay, format);
>>>> +	if (IS_ERR(buffer))
>>>> +		return buffer;
>>>> +
>>>> +	ret = drm_client_buffer_addfb(buffer, mode);
>>>> +	if (ret) {
>>>> +		drm_client_buffer_delete(buffer);
>>>> +		return ERR_PTR(ret);
>>>> +	}
>>>> +
>>>> +	return buffer;
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_framebuffer_create);
>>>> +
>>>> +void drm_client_framebuffer_delete(struct drm_client_buffer *buffer)
>>>> +{
>>>> +	drm_client_buffer_rmfb(buffer);
>>>> +	drm_client_buffer_delete(buffer);
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_framebuffer_delete);
>>>> +
>>>> +struct drm_client_buffer *
>>>> +drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height,
>>>> +			 u32 format)
>>>> +{
>>>> +	struct drm_mode_create_dumb dumb_args = { 0 };
>>>> +	struct drm_prime_handle prime_args = { 0 };
>>>> +	struct drm_client_buffer *buffer;
>>>> +	struct dma_buf *dma_buf;
>>>> +	void *vaddr;
>>>> +	int ret;
>>>> +
>>>> +	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
>>>> +	if (!buffer)
>>>> +		return ERR_PTR(-ENOMEM);
>>>> +
>>>> +	ret = drm_client_get_file(client);
>>>> +	if (ret)
>>>> +		goto err_free;
>>>> +
>>>> +	buffer->client = client;
>>>> +	buffer->width = width;
>>>> +	buffer->height = height;
>>>> +	buffer->format = format;
>>>> +
>>>> +	dumb_args.width = buffer->width;
>>>> +	dumb_args.height = buffer->height;
>>>> +	dumb_args.bpp = drm_format_plane_cpp(format, 0) * 8;
>>>> +	ret = drm_mode_create_dumb(client->dev, &dumb_args, client->file);
>>>> +	if (ret)
>>>> +		goto err_put_file;
>>>> +
>>>> +	buffer->handle = dumb_args.handle;
>>>> +	buffer->pitch = dumb_args.pitch;
>>>> +	buffer->size = dumb_args.size;
>>>> +
>>>> +	prime_args.handle = dumb_args.handle;
>>>> +	ret = drm_prime_handle_to_fd(client->dev, &prime_args, client->file);
>>>> +	if (ret)
>>>> +		goto err_delete;
>>>> +
>>>> +	dma_buf = dma_buf_get(prime_args.fd);
>>>> +	if (IS_ERR(dma_buf)) {
>>>> +		ret = PTR_ERR(dma_buf);
>>>> +		goto err_delete;
>>>> +	}
>>>> +
>>>> +	buffer->dma_buf = dma_buf;
>>>> +
>>>> +	vaddr = dma_buf_vmap(dma_buf);
>>>> +	if (!vaddr) {
>>>> +		ret = -ENOMEM;
>>>> +		goto err_delete;
>>>> +	}
>>>> +
>>>> +	buffer->vaddr = vaddr;
>>>> +
>>>> +	return buffer;
>>>> +
>>>> +err_delete:
>>>> +	drm_client_buffer_delete(buffer);
>>>> +err_put_file:
>>>> +	drm_client_put_file(client);
>>>> +err_free:
>>>> +	kfree(buffer);
>>>> +
>>>> +	return ERR_PTR(ret);
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_buffer_create);
>>>> +
>>>> +void drm_client_buffer_delete(struct drm_client_buffer *buffer)
>>>> +{
>>>> +	if (!buffer)
>>>> +		return;
>>>> +
>>>> +	if (buffer->vaddr)
>>>> +		dma_buf_vunmap(buffer->dma_buf, buffer->vaddr);
>>>> +
>>>> +	if (buffer->dma_buf)
>>>> +		dma_buf_put(buffer->dma_buf);
>>>> +
>>>> +	drm_mode_destroy_dumb(buffer->client->dev, buffer->handle,
>>>> +			      buffer->client->file);
>>>> +	drm_client_put_file(buffer->client);
>>>> +	kfree(buffer);
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_buffer_delete);
>>>> +
>>>> +int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
>>>> +			    struct drm_mode_modeinfo *mode)
>>>> +{
>>>> +	struct drm_client_dev *client = buffer->client;
>>>> +	struct drm_mode_fb_cmd2 fb_req = { };
>>>> +	unsigned int num_fbs, *fb_ids;
>>>> +	int i, ret;
>>>> +
>>>> +	if (buffer->num_fbs)
>>>> +		return -EINVAL;
>>>> +
>>>> +	if (mode->hdisplay > buffer->width || mode->vdisplay > buffer->height)
>>>> +		return -EINVAL;
>>>> +
>>>> +	num_fbs = buffer->height / mode->vdisplay;
>>>> +	fb_ids = kcalloc(num_fbs, sizeof(*fb_ids), GFP_KERNEL);
>>>> +	if (!fb_ids)
>>>> +		return -ENOMEM;
>>>> +
>>>> +	fb_req.width = mode->hdisplay;
>>>> +	fb_req.height = mode->vdisplay;
>>>> +	fb_req.pixel_format = buffer->format;
>>>> +	fb_req.handles[0] = buffer->handle;
>>>> +	fb_req.pitches[0] = buffer->pitch;
>>>> +
>>>> +	for (i = 0; i < num_fbs; i++) {
>>>> +		fb_req.offsets[0] = i * mode->vdisplay * buffer->pitch;
>>>> +		ret = drm_mode_addfb2(client->dev, &fb_req, client->file,
>>>> +				      client->funcs->name);
>>>> +		if (ret)
>>>> +			goto err_remove;
>>>> +		fb_ids[i] = fb_req.fb_id;
>>>> +	}
>>>> +
>>>> +	buffer->fb_ids = fb_ids;
>>>> +	buffer->num_fbs = num_fbs;
>>>> +
>>>> +	return 0;
>>>> +
>>>> +err_remove:
>>>> +	for (i--; i >= 0; i--)
>>>> +		drm_mode_rmfb(client->dev, fb_ids[i], client->file);
>>>> +	kfree(fb_ids);
>>>> +
>>>> +	return ret;
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_buffer_addfb);
>>>> +
>>>> +int drm_client_buffer_rmfb(struct drm_client_buffer *buffer)
>>>> +{
>>>> +	unsigned int i;
>>>> +	int ret;
>>>> +
>>>> +	if (!buffer || !buffer->num_fbs)
>>>> +		return 0;
>>>> +
>>>> +	for (i = 0; i < buffer->num_fbs; i++) {
>>>> +		ret = drm_mode_rmfb(buffer->client->dev, buffer->fb_ids[i],
>>>> +				    buffer->client->file);
>>>> +		if (ret)
>>>> +			DRM_DEV_ERROR(buffer->client->dev->dev,
>>>> +				      "Error removing FB:%u (%d)\n",
>>>> +				      buffer->fb_ids[i], ret);
>>>> +	}
>>>> +
>>>> +	kfree(buffer->fb_ids);
>>>> +	buffer->fb_ids = NULL;
>>>> +	buffer->num_fbs = 0;
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +EXPORT_SYMBOL(drm_client_buffer_rmfb);
>>>> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
>>>> index f869de185986..db161337d87c 100644
>>>> --- a/drivers/gpu/drm/drm_drv.c
>>>> +++ b/drivers/gpu/drm/drm_drv.c
>>>> @@ -33,6 +33,7 @@
>>>>    #include <linux/mount.h>
>>>>    #include <linux/slab.h>
>>>> +#include <drm/drm_client.h>
>>>>    #include <drm/drm_drv.h>
>>>>    #include <drm/drmP.h>
>>>> @@ -463,6 +464,7 @@ int drm_dev_init(struct drm_device *dev,
>>>>    	dev->driver = driver;
>>>>    	INIT_LIST_HEAD(&dev->filelist);
>>>> +	INIT_LIST_HEAD(&dev->filelist_internal);
>>>>    	INIT_LIST_HEAD(&dev->ctxlist);
>>>>    	INIT_LIST_HEAD(&dev->vmalist);
>>>>    	INIT_LIST_HEAD(&dev->maplist);
>>>> @@ -787,6 +789,8 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags)
>>>>    		 dev->dev ? dev_name(dev->dev) : "virtual device",
>>>>    		 dev->primary->index);
>>>> +	drm_client_dev_register(dev);
>>>> +
>>>>    	goto out_unlock;
>>>>    err_minors:
>>>> @@ -839,6 +843,8 @@ void drm_dev_unregister(struct drm_device *dev)
>>>>    	drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
>>>>    	drm_minor_unregister(dev, DRM_MINOR_RENDER);
>>>>    	drm_minor_unregister(dev, DRM_MINOR_CONTROL);
>>>> +
>>>> +	drm_client_dev_unregister(dev);
>>>>    }
>>>>    EXPORT_SYMBOL(drm_dev_unregister);
>>>> diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
>>>> index 55505378df47..bcc688e58776 100644
>>>> --- a/drivers/gpu/drm/drm_file.c
>>>> +++ b/drivers/gpu/drm/drm_file.c
>>>> @@ -35,6 +35,7 @@
>>>>    #include <linux/slab.h>
>>>>    #include <linux/module.h>
>>>> +#include <drm/drm_client.h>
>>>>    #include <drm/drm_file.h>
>>>>    #include <drm/drmP.h>
>>>> @@ -443,6 +444,8 @@ void drm_lastclose(struct drm_device * dev)
>>>>    	if (drm_core_check_feature(dev, DRIVER_LEGACY))
>>>>    		drm_legacy_dev_reinit(dev);
>>>> +
>>>> +	drm_client_dev_lastclose(dev);
>>>>    }
>>>>    /**
>>>> diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
>>>> index 2d1643bdae78..5d2a6c6717f5 100644
>>>> --- a/drivers/gpu/drm/drm_probe_helper.c
>>>> +++ b/drivers/gpu/drm/drm_probe_helper.c
>>>> @@ -33,6 +33,7 @@
>>>>    #include <linux/moduleparam.h>
>>>>    #include <drm/drmP.h>
>>>> +#include <drm/drm_client.h>
>>>>    #include <drm/drm_crtc.h>
>>>>    #include <drm/drm_fourcc.h>
>>>>    #include <drm/drm_crtc_helper.h>
>>>> @@ -563,6 +564,8 @@ void drm_kms_helper_hotplug_event(struct drm_device *dev)
>>>>    	drm_sysfs_hotplug_event(dev);
>>>>    	if (dev->mode_config.funcs->output_poll_changed)
>>>>    		dev->mode_config.funcs->output_poll_changed(dev);
>>>> +
>>>> +	drm_client_dev_hotplug(dev);
>>>>    }
>>>>    EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
>>>> diff --git a/include/drm/drm_client.h b/include/drm/drm_client.h
>>>> new file mode 100644
>>>> index 000000000000..88f6f87919c5
>>>> --- /dev/null
>>>> +++ b/include/drm/drm_client.h
>>>> @@ -0,0 +1,192 @@
>>>> +/* SPDX-License-Identifier: GPL-2.0 */
>>>> +
>>>> +#include <linux/mutex.h>
>>>> +
>>>> +struct dma_buf;
>>>> +struct drm_clip_rect;
>>>> +struct drm_device;
>>>> +struct drm_file;
>>>> +struct drm_mode_modeinfo;
>>>> +
>>>> +struct drm_client_dev;
>>>> +
>>>> +/**
>>>> + * struct drm_client_funcs - DRM client  callbacks
>>>> + */
>>>> +struct drm_client_funcs {
>>>> +	/**
>>>> +	 * @name:
>>>> +	 *
>>>> +	 * Name of the client.
>>>> +	 */
>>>> +	const char *name;
>>>> +
>>>> +	/**
>>>> +	 * @new:
>>>> +	 *
>>>> +	 * Called when a client or a &drm_device is registered.
>>>> +	 * If the callback returns anything but zero, then this client instance
>>>> +	 * is dropped.
>>>> +	 *
>>>> +	 * This callback is mandatory.
>>>> +	 */
>>>> +	int (*new)(struct drm_client_dev *client);
>>>> +
>>>> +	/**
>>>> +	 * @remove:
>>>> +	 *
>>>> +	 * Called when a &drm_device is unregistered or the client is
>>>> +	 * unregistered. If zero is returned drm_client_free() is called
>>>> +	 * automatically. If the client can't drop it's resources it should
>>>> +	 * return non-zero and call drm_client_free() later.
>>>> +	 *
>>>> +	 * This callback is optional.
>>>> +	 */
>>>> +	int (*remove)(struct drm_client_dev *client);
>>>> +
>>>> +	/**
>>>> +	 * @lastclose:
>>>> +	 *
>>>> +	 * Called on drm_lastclose(). The first client instance in the list
>>>> +	 * that returns zero gets the privilege to restore and no more clients
>>>> +	 * are called.
>>>> +	 *
>>>> +	 * This callback is optional.
>>>> +	 */
>>>> +	int (*lastclose)(struct drm_client_dev *client);
>>>> +
>>>> +	/**
>>>> +	 * @hotplug:
>>>> +	 *
>>>> +	 * Called on drm_kms_helper_hotplug_event().
>>>> +	 *
>>>> +	 * This callback is optional.
>>>> +	 */
>>>> +	int (*hotplug)(struct drm_client_dev *client);
>>>> +
>>>> +// TODO
>>>> +//	void (*suspend)(struct drm_client_dev *client);
>>>> +//	void (*resume)(struct drm_client_dev *client);
>>>> +};
>>>> +
>>>> +/**
>>>> + * struct drm_client_dev - DRM client instance
>>>> + */
>>>> +struct drm_client_dev {
>>>> +	struct list_head list;
>>>> +	struct drm_device *dev;
>>>> +	const struct drm_client_funcs *funcs;
>>>> +	struct mutex lock;
>>>> +	struct drm_file *file;
>>>> +	unsigned int file_ref_count;
>>>> +	u32 *crtcs;
>>>> +	unsigned int num_crtcs;
>>>> +	u32 min_width;
>>>> +	u32 max_width;
>>>> +	u32 min_height;
>>>> +	u32 max_height;
>>>> +	void *private;
>>>> +};
>>>> +
>>>> +void drm_client_free(struct drm_client_dev *client);
>>>> +int drm_client_register(const struct drm_client_funcs *funcs);
>>>> +void drm_client_unregister(const struct drm_client_funcs *funcs);
>>>> +
>>>> +void drm_client_dev_register(struct drm_device *dev);
>>>> +void drm_client_dev_unregister(struct drm_device *dev);
>>>> +void drm_client_dev_hotplug(struct drm_device *dev);
>>>> +void drm_client_dev_lastclose(struct drm_device *dev);
>>>> +
>>>> +int drm_client_get_file(struct drm_client_dev *client);
>>>> +void drm_client_put_file(struct drm_client_dev *client);
>>>> +struct drm_event *
>>>> +drm_client_read_event(struct drm_client_dev *client, bool block);
>>>> +
>>>> +struct drm_client_connector {
>>>> +	unsigned int conn_id;
>>>> +	unsigned int status;
>>>> +	unsigned int crtc_id;
>>>> +	struct drm_mode_modeinfo *modes;
>>>> +	unsigned int num_modes;
>>>> +	bool has_tile;
>>>> +	int tile_group;
>>>> +	u8 tile_h_loc, tile_v_loc;
>>>> +};
>>>> +
>>>> +struct drm_client_display {
>>>> +	struct drm_client_dev *client;
>>>> +
>>>> +	struct drm_client_connector **connectors;
>>>> +	unsigned int num_connectors;
>>>> +
>>>> +	struct mutex modes_lock;
>>>> +	struct drm_mode_modeinfo *modes;
>>>> +	unsigned int num_modes;
>>>> +
>>>> +	bool cloned;
>>>> +	bool no_flushing;
>>>> +};
>>>> +
>>>> +void drm_client_display_free(struct drm_client_display *display);
>>>> +struct drm_client_display *
>>>> +drm_client_display_get_first_enabled(struct drm_client_dev *client, bool strict);
>>>> +
>>>> +int drm_client_display_update_modes(struct drm_client_display *display,
>>>> +				    bool *mode_changed);
>>>> +
>>>> +static inline bool
>>>> +drm_client_display_is_tiled(struct drm_client_display *display)
>>>> +{
>>>> +	return !display->cloned && display->num_connectors > 1;
>>>> +}
>>>> +
>>>> +int drm_client_display_dpms(struct drm_client_display *display, int mode);
>>>> +int drm_client_display_wait_vblank(struct drm_client_display *display);
>>>> +
>>>> +struct drm_mode_modeinfo *
>>>> +drm_client_display_first_mode(struct drm_client_display *display);
>>>> +struct drm_mode_modeinfo *
>>>> +drm_client_display_next_mode(struct drm_client_display *display,
>>>> +			     struct drm_mode_modeinfo *mode);
>>>> +
>>>> +#define drm_client_display_for_each_mode(display, mode) \
>>>> +	for (mode = drm_client_display_first_mode(display); mode; \
>>>> +	     mode = drm_client_display_next_mode(display, mode))
>>>> +
>>>> +unsigned int
>>>> +drm_client_display_preferred_depth(struct drm_client_display *display);
>>>> +
>>>> +int drm_client_display_commit_mode(struct drm_client_display *display,
>>>> +				   u32 fb_id, struct drm_mode_modeinfo *mode);
>>>> +unsigned int drm_client_display_current_fb(struct drm_client_display *display);
>>>> +int drm_client_display_flush(struct drm_client_display *display, u32 fb_id,
>>>> +			     struct drm_clip_rect *clips, unsigned int num_clips);
>>>> +int drm_client_display_page_flip(struct drm_client_display *display, u32 fb_id,
>>>> +				 bool event);
>>>> +
>>>> +struct drm_client_buffer {
>>>> +	struct drm_client_dev *client;
>>>> +	u32 width;
>>>> +	u32 height;
>>>> +	u32 format;
>>>> +	u32 handle;
>>>> +	u32 pitch;
>>>> +	u64 size;
>>>> +	struct dma_buf *dma_buf;
>>>> +	void *vaddr;
>>>> +
>>>> +	unsigned int *fb_ids;
>>>> +	unsigned int num_fbs;
>>>> +};
>>>> +
>>>> +struct drm_client_buffer *
>>>> +drm_client_framebuffer_create(struct drm_client_dev *client,
>>>> +			      struct drm_mode_modeinfo *mode, u32 format);
>>>> +void drm_client_framebuffer_delete(struct drm_client_buffer *buffer);
>>>> +struct drm_client_buffer *
>>>> +drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height,
>>>> +			 u32 format);
>>>> +void drm_client_buffer_delete(struct drm_client_buffer *buffer);
>>>> +int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
>>>> +			    struct drm_mode_modeinfo *mode);
>>>> +int drm_client_buffer_rmfb(struct drm_client_buffer *buffer);
>>>> diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h
>>>> index 7c4fa32f3fc6..32dfed3d5a86 100644
>>>> --- a/include/drm/drm_device.h
>>>> +++ b/include/drm/drm_device.h
>>>> @@ -67,6 +67,7 @@ struct drm_device {
>>>>    	struct mutex filelist_mutex;
>>>>    	struct list_head filelist;
>>>> +	struct list_head filelist_internal;
>>>>    	/** \name Memory management */
>>>>    	/*@{ */
>>>> diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
>>>> index 5176c3797680..39af8a4be7b3 100644
>>>> --- a/include/drm/drm_file.h
>>>> +++ b/include/drm/drm_file.h
>>>> @@ -248,6 +248,13 @@ struct drm_file {
>>>>    	 */
>>>>    	void *driver_priv;
>>>> +	/**
>>>> +	 * @user_priv:
>>>> +	 *
>>>> +	 * Optional pointer for user private data. Useful for in-kernel clients.
>>>> +	 */
>>>> +	void *user_priv;
>>>> +
>>>>    	/**
>>>>    	 * @fbs:
>>>>    	 *
>>>> -- 
>>>> 2.15.1
>>>>

Daniel Vetter March 13, 2018, 3:11 p.m. UTC | #5

On Mon, Mar 12, 2018 at 09:21:40PM +0100, Noralf Tr??nnes wrote:
> 
> Den 12.03.2018 17.51, skrev Daniel Vetter:
> > On Thu, Mar 08, 2018 at 06:12:11PM +0100, Noralf Tr??nnes wrote:
> > > Den 06.03.2018 09.56, skrev Daniel Vetter:
> > > > On Thu, Feb 22, 2018 at 09:06:50PM +0100, Noralf Tr??nnes wrote:
> > > > > This adds an API for writing in-kernel clients.
> > > > > 
> > > > > TODO:
> > > > > - Flesh out and complete documentation.
> > > > > - Cloned displays is not tested.
> > > > > - Complete tiled display support and test it.
> > > > > - Test plug/unplug different monitors.
> > > > > - A runtime knob to prevent clients from attaching for debugging purposes.
> > > > > - Maybe a way to unbind individual client instances.
> > > > > - Maybe take the sysrq support in drm_fb_helper and move it here somehow.
> > > > > - Add suspend/resume callbacks.
> > > > >     Does anyone know why fbdev requires suspend/resume?
> > > > > 
> > > > > Signed-off-by: Noralf Tr??nnes <[e-mail]>
> > > > The core client api I like. Some of the opens I'm seeing:
> > > > 
> > > > - If we go with using the internal kms api directly instead of IOCTL
> > > >     wrappers then a huge pile of the functions you have here aren't needed
> > > >     (e.g. all the event stuff we can just directly use vblank events instead
> > > >     of all the wrapping). I'm leaning ever more into that direction, since
> > > >     much less code to add.
> > > Looking at drm_fb_helper once again I now see an opportunity to simplify
> > > the modesetting code by nuking drm_fb_helper_connector and stop
> > > maintaining an array of connectors. It looks to be possible to just
> > > create an array temporarily in drm_setup_crtcs() for the duration of the
> > > function. The connectors we care about are ref counted and attached to
> > > modesets. This would remove the need for drm_fb_helper_add_one_connector().
> > > 
> > > So I might be able to do struct drm_fb_helper_crtc -> drm_client_crtc
> > > and let the client API take over drm_setup_crtcs(). I'll give it a try.
> > I'm more wondering why we need drm_client_crtc at all, why is drm_crtc not
> > good enough. Or maybe I'm missing something. Imo ioctl wrappers should be
> > the exception where we really, really need them (because the backend of
> > the ioctl isn't implemented in a generic way, e.g. dumb buffers), not for
> > stuff where we already have a perfectly useable in-kernel abi (anything
> > related to modesetting).
> 
> I was talking about moving the modesetting code from drm_fb_helper.c
> to drm_client.c, which meant moving 'struct drm_fb_helper_crtc' as well.
> 
> struct drm_fb_helper_crtc {
>     struct drm_mode_set mode_set;
>     struct drm_display_mode *desired_mode;
>     int x, y;
> };
> 
> But maybe we can get rid of that struct as well.
> The info it contains is also available in drm_mode_set:

drm_mode_set is the uapi struct for the legacy ioctl, but yeah I guess we
can recycle that. And I didn't understand what you wanted to do,
extracting the fbdev helper might make sense. But most of the code seems
fbdev specific, so not sure how much use that would be in other clients.

There's also a bit the problem that it's crufty (it started out as
something that was fully integrated into drivers and digging around in
driver internals directly, hence also the convoluted allocation logic).
-Daniel

> 
> static void drm_setup_crtcs(struct drm_fb_helper *fb_helper,
>                 u32 width, u32 height)
> {
> ...
>     drm_fb_helper_for_each_connector(fb_helper, i) {
>         struct drm_display_mode *mode = modes[i];
>         struct drm_fb_helper_crtc *fb_crtc = crtcs[i];
>         struct drm_fb_offset *offset = &offsets[i];
> 
>         if (mode && fb_crtc) {
>             struct drm_mode_set *modeset = &fb_crtc->mode_set;
> 
>             fb_crtc->desired_mode = mode;
>             fb_crtc->x = offset->x;
>             fb_crtc->y = offset->y;
>             modeset->mode = drm_mode_duplicate(dev,
>                                fb_crtc->desired_mode);
>             modeset->x = offset->x;
>             modeset->y = offset->y;
>         }
>     }
> 
> I took the hint about my ioctl wrappers :-)
> 
> Noralf.
> 
> > 
> > And in a way the ioctl wrappers wouldn't really be ioctl wrappers
> > conceptually, but simple share some of the same code with the ioctl call
> > chain. The idea is to provide some minimal wrappar around the ->dumb*
> > callbacks.
> > 
> > Anything else is not needed, I think.
> > 
> > > There is one challenge I see upfront and that's the i915 fb_helper
> > > callback in drm_setup_crtcs().
> > > 
> > > > - The register/unregister model needs more thought. Allowing both clients
> > > >     to register whenever they want to, and drm_device instances to come and
> > > >     go is what fbcon has done, and the resulting locking is a horror show.
> > > > 
> > > >     I think if we require that all in-kernel drm_clients are registers when
> > > >     loading drm.ko (and enabled/disabled only per module options and
> > > >     Kconfig), then we can throw out all the locking. That avoids a lot of
> > > >     the headaches.
> > > > 
> > > >     2nd, if the list of clients is static over the lifetime of drm.ko, we
> > > >     also don't need to iterate existing drivers. Which avoids me having to
> > > >     review the iterator patch (that's the other aspect where fbcon totally
> > > >     falls over and essentially just ignores a bunch of races).
> > > Are you talking about linking the clients into drm.ko?
> > > 
> > > drivers/gpu/drm/Makefile:
> > > 
> > > drm-$(CONFIG_DRM_CLIENT_BOOTSPLASH) += client/drm_bootsplash.o
> > > 
> > > drivers/gpu/drm/drm_drv.c:
> > > 
> > > ??static int __init drm_core_init(void)
> > > ??{
> > > +?????? drm_bootsplash_register();
> > > +?????? drm_fbdev_register();
> > > ??}
> > > 
> > > drivers/gpu/drm/drm_internal.h:
> > > 
> > > #ifdef DRM_CLIENT_BOOTSPLASH
> > > void drm_bootsplash_register(void);
> > > #else
> > > static inline void drm_bootsplash_register(void)
> > > {
> > > }
> > > #endif
> > > 
> > > drivers/gpu/drm/client/drm_bootsplash.c:
> > > 
> > > static const struct drm_client_funcs drm_bootsplash_funcs = {
> > > ?????? .name?????? ?????? = "drm_bootsplash",
> > > ?????? .new?????? ?????? = drm_bootsplash_new,
> > > ?????? .remove?????? ?????? = drm_bootsplash_remove,
> > > ?????? .hotplug?????? = drm_bootsplash_hotplug,
> > > };
> > > 
> > > void drm_bootsplash_register(void)
> > > {
> > > ?????? drm_client_register(&drm_bootsplash_funcs);
> > > }
> > > 
> > > drivers/gpu/drm/drm_client.c:
> > > 
> > > static LIST_HEAD(drm_client_funcs_list);
> > > 
> > > void drm_client_register(const struct drm_client_funcs *funcs)
> > > {
> > > ?????? struct drm_client_funcs_entry *funcs_entry;
> > > 
> > > ?????? funcs_entry = kzalloc(sizeof(*funcs_entry), GFP_KERNEL);
> > > ?????? if (!funcs_entry) {
> > > ?????? ?????? DRM_ERROR("Failed to register: %s\n", funcs->name);
> > > ?????? ?????? return;
> > > ?????? }
> > > 
> > > ?????? funcs_entry->funcs = funcs;
> > > 
> > > ?????? list_add(&funcs_entry->list, &drm_client_funcs_list);
> > > 
> > > ?????? DRM_DEBUG_KMS("%s\n", funcs->name);
> > > }
> > > 
> > > 
> > > And each client having a runtime enable/disable knob:
> > > 
> > > drivers/gpu/drm/client/drm_bootsplash.c:
> > > 
> > > static bool drm_bootsplash_enabled = true;
> > > module_param_named(bootsplash_enabled, drm_bootsplash_enabled, bool, 0600);
> > > MODULE_PARM_DESC(bootsplash_enabled, "Enable bootsplash client
> > > [default=true]");
> > 
> > Yup, pretty much.
> > 
> > > Simple USB Display
> > > A few months back while looking at the udl shmem code, I got the idea
> > > that I could turn a Raspberry Pi Zero into a $5 USB to HDMI/DSI/DPI/DBI/TV
> > > adapter. The host side would be a simple tinydrm driver using the kernel
> > > compression lib to speed up transfers. The gadget/device side would be a
> > > userspace app decompressing the buffer into an exported dumb buffer.
> > > 
> > > While working with this client API I realized that I could use it and
> > > write a kernel gadget driver instead avoiding the challenge of going
> > > back and forth to userspace with the framebuffer. For such a client I
> > > would have preferred it to be a loadable module not linked into drm.ko
> > > to increase the chance that distributions would enable it.
> > I think that we can do as a loadable client, since you probably want some
> > configfs interface to define which drm driver it should control. The
> > reason behind the static list of built-in clients is purely for the
> > auto-register stuff that we want for fbdev emulation and other things.
> > Auto-registration where both sides can be loaded in any order is real pain
> > wrt locking. Explicit registration where you can load both sides is
> > totally fine and I think would cover your usb gadget display driver
> > use-case.
> > 
> > btw usb gadget driver to drive drm kms drivers sounds like a really cool
> > thing.
> > -Daniel
> > 
> > > Noralf.
> > > 
> > > > > ---
> > > > >    drivers/gpu/drm/Kconfig             |    2 +
> > > > >    drivers/gpu/drm/Makefile            |    3 +-
> > > > >    drivers/gpu/drm/client/Kconfig      |    4 +
> > > > >    drivers/gpu/drm/client/Makefile     |    1 +
> > > > >    drivers/gpu/drm/client/drm_client.c | 1612 +++++++++++++++++++++++++++++++++++
> > > > I'd move this into main drm/ directory, it's fairly core stuff.
> > > > 
> > > > >    drivers/gpu/drm/drm_drv.c           |    6 +
> > > > >    drivers/gpu/drm/drm_file.c          |    3 +
> > > > >    drivers/gpu/drm/drm_probe_helper.c  |    3 +
> > > > >    include/drm/drm_client.h            |  192 +++++
> > > > >    include/drm/drm_device.h            |    1 +
> > > > >    include/drm/drm_file.h              |    7 +
> > > > >    11 files changed, 1833 insertions(+), 1 deletion(-)
> > > > >    create mode 100644 drivers/gpu/drm/client/Kconfig
> > > > >    create mode 100644 drivers/gpu/drm/client/Makefile
> > > > >    create mode 100644 drivers/gpu/drm/client/drm_client.c
> > > > >    create mode 100644 include/drm/drm_client.h
> > > > > 
> > > > > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> > > > > index deeefa7a1773..d4ae15f9ee9f 100644
> > > > > --- a/drivers/gpu/drm/Kconfig
> > > > > +++ b/drivers/gpu/drm/Kconfig
> > > > > @@ -154,6 +154,8 @@ config DRM_SCHED
> > > > >    	tristate
> > > > >    	depends on DRM
> > > > > +source "drivers/gpu/drm/client/Kconfig"
> > > > > +
> > > > >    source "drivers/gpu/drm/i2c/Kconfig"
> > > > >    source "drivers/gpu/drm/arm/Kconfig"
> > > > > diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> > > > > index 50093ff4479b..8e06dc7eeca1 100644
> > > > > --- a/drivers/gpu/drm/Makefile
> > > > > +++ b/drivers/gpu/drm/Makefile
> > > > > @@ -18,7 +18,7 @@ drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
> > > > >    		drm_encoder.o drm_mode_object.o drm_property.o \
> > > > >    		drm_plane.o drm_color_mgmt.o drm_print.o \
> > > > >    		drm_dumb_buffers.o drm_mode_config.o drm_vblank.o \
> > > > > -		drm_syncobj.o drm_lease.o
> > > > > +		drm_syncobj.o drm_lease.o client/drm_client.o
> > > > >    drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o
> > > > >    drm-$(CONFIG_DRM_VM) += drm_vm.o
> > > > > @@ -103,3 +103,4 @@ obj-$(CONFIG_DRM_MXSFB)	+= mxsfb/
> > > > >    obj-$(CONFIG_DRM_TINYDRM) += tinydrm/
> > > > >    obj-$(CONFIG_DRM_PL111) += pl111/
> > > > >    obj-$(CONFIG_DRM_TVE200) += tve200/
> > > > > +obj-y			+= client/
> > > > > diff --git a/drivers/gpu/drm/client/Kconfig b/drivers/gpu/drm/client/Kconfig
> > > > > new file mode 100644
> > > > > index 000000000000..4bb8e4655ff7
> > > > > --- /dev/null
> > > > > +++ b/drivers/gpu/drm/client/Kconfig
> > > > > @@ -0,0 +1,4 @@
> > > > > +menu "DRM Clients"
> > > > > +	depends on DRM
> > > > > +
> > > > > +endmenu
> > > > > diff --git a/drivers/gpu/drm/client/Makefile b/drivers/gpu/drm/client/Makefile
> > > > > new file mode 100644
> > > > > index 000000000000..f66554cd5c45
> > > > > --- /dev/null
> > > > > +++ b/drivers/gpu/drm/client/Makefile
> > > > > @@ -0,0 +1 @@
> > > > > +# SPDX-License-Identifier: GPL-2.0
> > > > > diff --git a/drivers/gpu/drm/client/drm_client.c b/drivers/gpu/drm/client/drm_client.c
> > > > > new file mode 100644
> > > > > index 000000000000..a633bf747316
> > > > > --- /dev/null
> > > > > +++ b/drivers/gpu/drm/client/drm_client.c
> > > > > @@ -0,0 +1,1612 @@
> > > > > +// SPDX-License-Identifier: GPL-2.0
> > > > > +// Copyright 2018 Noralf Tr??nnes
> > > > > +
> > > > > +#include <linux/dma-buf.h>
> > > > > +#include <linux/list.h>
> > > > > +#include <linux/mutex.h>
> > > > > +#include <linux/module.h>
> > > > > +#include <linux/slab.h>
> > > > > +
> > > > > +#include <drm/drm_client.h>
> > > > > +#include <drm/drm_connector.h>
> > > > > +#include <drm/drm_drv.h>
> > > > > +#include <drm/drm_file.h>
> > > > > +#include <drm/drm_ioctl.h>
> > > > > +#include <drm/drmP.h>
> > > > > +
> > > > > +#include "drm_crtc_internal.h"
> > > > > +#include "drm_internal.h"
> > > > > +
> > > > > +struct drm_client_funcs_entry {
> > > > > +	struct list_head list;
> > > > > +	const struct drm_client_funcs *funcs;
> > > > > +};
> > > > > +
> > > > > +static LIST_HEAD(drm_client_list);
> > > > I think the client list itself should be on the drm_device, not in one
> > > > global list that mixes up all the clients of all the drm_devices.
> > > > 
> > > > I'll skip reviewing details since we have a bunch of high-level questions
> > > > to figure out first.
> > > > -Daniel
> > > > 
> > > > > +static LIST_HEAD(drm_client_funcs_list);
> > > > > +static DEFINE_MUTEX(drm_client_list_lock);
> > > > > +
> > > > > +static void drm_client_new(struct drm_device *dev,
> > > > > +			   const struct drm_client_funcs *funcs)
> > > > > +{
> > > > > +	struct drm_client_dev *client;
> > > > > +	int ret;
> > > > > +
> > > > > +	lockdep_assert_held(&drm_client_list_lock);
> > > > > +
> > > > > +	client = kzalloc(sizeof(*client), GFP_KERNEL);
> > > > > +	if (!client)
> > > > > +		return;
> > > > > +
> > > > > +	mutex_init(&client->lock);
> > > > > +	client->dev = dev;
> > > > > +	client->funcs = funcs;
> > > > > +
> > > > > +	ret = funcs->new(client);
> > > > > +	DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n", funcs->name, ret);
> > > > > +	if (ret) {
> > > > > +		drm_client_free(client);
> > > > > +		return;
> > > > > +	}
> > > > > +
> > > > > +	list_add(&client->list, &drm_client_list);
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * drm_client_free - Free DRM client resources
> > > > > + * @client: DRM client
> > > > > + *
> > > > > + * This is called automatically on client removal unless the client returns
> > > > > + * non-zero in the &drm_client_funcs->remove callback. The fbdev client does
> > > > > + * this when it can't close &drm_file because userspace has an open fd.
> > > > > + */
> > > > > +void drm_client_free(struct drm_client_dev *client)
> > > > > +{
> > > > > +	DRM_DEV_DEBUG_KMS(client->dev->dev, "%s\n", client->funcs->name);
> > > > > +	if (WARN_ON(client->file)) {
> > > > > +		client->file_ref_count = 1;
> > > > > +		drm_client_put_file(client);
> > > > > +	}
> > > > > +	mutex_destroy(&client->lock);
> > > > > +	kfree(client->crtcs);
> > > > > +	kfree(client);
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_free);
> > > > > +
> > > > > +static void drm_client_remove(struct drm_client_dev *client)
> > > > > +{
> > > > > +	lockdep_assert_held(&drm_client_list_lock);
> > > > > +
> > > > > +	list_del(&client->list);
> > > > > +
> > > > > +	if (!client->funcs->remove || !client->funcs->remove(client))
> > > > > +		drm_client_free(client);
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * drm_client_register - Register a DRM client
> > > > > + * @funcs: Client callbacks
> > > > > + *
> > > > > + * Returns:
> > > > > + * Zero on success, negative error code on failure.
> > > > > + */
> > > > > +int drm_client_register(const struct drm_client_funcs *funcs)
> > > > > +{
> > > > > +	struct drm_client_funcs_entry *funcs_entry;
> > > > > +	struct drm_device_list_iter iter;
> > > > > +	struct drm_device *dev;
> > > > > +
> > > > > +	funcs_entry = kzalloc(sizeof(*funcs_entry), GFP_KERNEL);
> > > > > +	if (!funcs_entry)
> > > > > +		return -ENOMEM;
> > > > > +
> > > > > +	funcs_entry->funcs = funcs;
> > > > > +
> > > > > +	mutex_lock(&drm_global_mutex);
> > > > > +	mutex_lock(&drm_client_list_lock);
> > > > > +
> > > > > +	drm_device_list_iter_begin(&iter);
> > > > > +	drm_for_each_device_iter(dev, &iter)
> > > > > +		if (drm_core_check_feature(dev, DRIVER_MODESET))
> > > > > +			drm_client_new(dev, funcs);
> > > > > +	drm_device_list_iter_end(&iter);
> > > > > +
> > > > > +	list_add(&funcs_entry->list, &drm_client_funcs_list);
> > > > > +
> > > > > +	mutex_unlock(&drm_client_list_lock);
> > > > > +	mutex_unlock(&drm_global_mutex);
> > > > > +
> > > > > +	DRM_DEBUG_KMS("%s\n", funcs->name);
> > > > > +
> > > > > +	return 0;
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_register);
> > > > > +
> > > > > +/**
> > > > > + * drm_client_unregister - Unregister a DRM client
> > > > > + * @funcs: Client callbacks
> > > > > + */
> > > > > +void drm_client_unregister(const struct drm_client_funcs *funcs)
> > > > > +{
> > > > > +	struct drm_client_funcs_entry *funcs_entry;
> > > > > +	struct drm_client_dev *client, *tmp;
> > > > > +
> > > > > +	mutex_lock(&drm_client_list_lock);
> > > > > +
> > > > > +	list_for_each_entry_safe(client, tmp, &drm_client_list, list) {
> > > > > +		if (client->funcs == funcs)
> > > > > +			drm_client_remove(client);
> > > > > +	}
> > > > > +
> > > > > +	list_for_each_entry(funcs_entry, &drm_client_funcs_list, list) {
> > > > > +		if (funcs_entry->funcs == funcs) {
> > > > > +			list_del(&funcs_entry->list);
> > > > > +			kfree(funcs_entry);
> > > > > +			break;
> > > > > +		}
> > > > > +	}
> > > > > +
> > > > > +	mutex_unlock(&drm_client_list_lock);
> > > > > +
> > > > > +	DRM_DEBUG_KMS("%s\n", funcs->name);
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_unregister);
> > > > > +
> > > > > +void drm_client_dev_register(struct drm_device *dev)
> > > > > +{
> > > > > +	struct drm_client_funcs_entry *funcs_entry;
> > > > > +
> > > > > +	/*
> > > > > +	 * Minors are created at the beginning of drm_dev_register(), but can
> > > > > +	 * be removed again if the function fails. Since we iterate DRM devices
> > > > > +	 * by walking DRM minors, we need to stay under this lock.
> > > > > +	 */
> > > > > +	lockdep_assert_held(&drm_global_mutex);
> > > > > +
> > > > > +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
> > > > > +		return;
> > > > > +
> > > > > +	mutex_lock(&drm_client_list_lock);
> > > > > +	list_for_each_entry(funcs_entry, &drm_client_funcs_list, list)
> > > > > +		drm_client_new(dev, funcs_entry->funcs);
> > > > > +	mutex_unlock(&drm_client_list_lock);
> > > > > +}
> > > > > +
> > > > > +void drm_client_dev_unregister(struct drm_device *dev)
> > > > > +{
> > > > > +	struct drm_client_dev *client, *tmp;
> > > > > +
> > > > > +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
> > > > > +		return;
> > > > > +
> > > > > +	mutex_lock(&drm_client_list_lock);
> > > > > +	list_for_each_entry_safe(client, tmp, &drm_client_list, list)
> > > > > +		if (client->dev == dev)
> > > > > +			drm_client_remove(client);
> > > > > +	mutex_unlock(&drm_client_list_lock);
> > > > > +}
> > > > > +
> > > > > +void drm_client_dev_hotplug(struct drm_device *dev)
> > > > > +{
> > > > > +	struct drm_client_dev *client;
> > > > > +	int ret;
> > > > > +
> > > > > +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
> > > > > +		return;
> > > > > +
> > > > > +	mutex_lock(&drm_client_list_lock);
> > > > > +	list_for_each_entry(client, &drm_client_list, list)
> > > > > +		if (client->dev == dev && client->funcs->hotplug) {
> > > > > +			ret = client->funcs->hotplug(client);
> > > > > +			DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n",
> > > > > +					  client->funcs->name, ret);
> > > > > +		}
> > > > > +	mutex_unlock(&drm_client_list_lock);
> > > > > +}
> > > > > +
> > > > > +void drm_client_dev_lastclose(struct drm_device *dev)
> > > > > +{
> > > > > +	struct drm_client_dev *client;
> > > > > +	int ret;
> > > > > +
> > > > > +	if (!drm_core_check_feature(dev, DRIVER_MODESET))
> > > > > +		return;
> > > > > +
> > > > > +	mutex_lock(&drm_client_list_lock);
> > > > > +	list_for_each_entry(client, &drm_client_list, list)
> > > > > +		if (client->dev == dev && client->funcs->lastclose) {
> > > > > +			ret = client->funcs->lastclose(client);
> > > > > +			DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n",
> > > > > +					  client->funcs->name, ret);
> > > > > +		}
> > > > > +	mutex_unlock(&drm_client_list_lock);
> > > > > +}
> > > > > +
> > > > > +/* Get static info */
> > > > > +static int drm_client_init(struct drm_client_dev *client, struct drm_file *file)
> > > > > +{
> > > > > +	struct drm_mode_card_res card_res = {};
> > > > > +	struct drm_device *dev = client->dev;
> > > > > +	u32 *crtcs;
> > > > > +	int ret;
> > > > > +
> > > > > +	ret = drm_mode_getresources(dev, &card_res, file, false);
> > > > > +	if (ret)
> > > > > +		return ret;
> > > > > +	if (!card_res.count_crtcs)
> > > > > +		return -ENOENT;
> > > > > +
> > > > > +	crtcs = kmalloc_array(card_res.count_crtcs, sizeof(*crtcs), GFP_KERNEL);
> > > > > +	if (!crtcs)
> > > > > +		return -ENOMEM;
> > > > > +
> > > > > +	card_res.count_fbs = 0;
> > > > > +	card_res.count_connectors = 0;
> > > > > +	card_res.count_encoders = 0;
> > > > > +	card_res.crtc_id_ptr = (unsigned long)crtcs;
> > > > > +
> > > > > +	ret = drm_mode_getresources(dev, &card_res, file, false);
> > > > > +	if (ret) {
> > > > > +		kfree(crtcs);
> > > > > +		return ret;
> > > > > +	}
> > > > > +
> > > > > +	client->crtcs = crtcs;
> > > > > +	client->num_crtcs = card_res.count_crtcs;
> > > > > +	client->min_width = card_res.min_width;
> > > > > +	client->max_width = card_res.max_width;
> > > > > +	client->min_height = card_res.min_height;
> > > > > +	client->max_height = card_res.max_height;
> > > > > +
> > > > > +	return 0;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * drm_client_get_file - Get a DRM file
> > > > > + * @client: DRM client
> > > > > + *
> > > > > + * This function makes sure the client has a &drm_file available. The client
> > > > > + * doesn't normally need to call this, since all client functions that depends
> > > > > + * on a DRM file will call it. A matching call to drm_client_put_file() is
> > > > > + * necessary.
> > > > > + *
> > > > > + * The reason for not opening a DRM file when a @client is created is because
> > > > > + * we have to take a ref on the driver module due to &drm_driver->postclose
> > > > > + * being called in drm_file_free(). Having a DRM file open for the lifetime of
> > > > > + * the client instance would block driver module unload.
> > > > > + *
> > > > > + * Returns:
> > > > > + * Zero on success, negative error code on failure.
> > > > > + */
> > > > > +int drm_client_get_file(struct drm_client_dev *client)
> > > > > +{
> > > > > +	struct drm_device *dev = client->dev;
> > > > > +	struct drm_file *file;
> > > > > +	int ret = 0;
> > > > > +
> > > > > +	mutex_lock(&client->lock);
> > > > > +
> > > > > +	if (client->file_ref_count++) {
> > > > > +		mutex_unlock(&client->lock);
> > > > > +		return 0;
> > > > > +	}
> > > > > +
> > > > > +	if (!try_module_get(dev->driver->fops->owner)) {
> > > > > +		ret = -ENODEV;
> > > > > +		goto err_unlock;
> > > > > +	}
> > > > > +
> > > > > +	drm_dev_get(dev);
> > > > > +
> > > > > +	file = drm_file_alloc(dev->primary);
> > > > > +	if (IS_ERR(file)) {
> > > > > +		ret = PTR_ERR(file);
> > > > > +		goto err_put;
> > > > > +	}
> > > > > +
> > > > > +	if (!client->crtcs) {
> > > > > +		ret = drm_client_init(client, file);
> > > > > +		if (ret)
> > > > > +			goto err_free;
> > > > > +	}
> > > > > +
> > > > > +	mutex_lock(&dev->filelist_mutex);
> > > > > +	list_add(&file->lhead, &dev->filelist_internal);
> > > > > +	mutex_unlock(&dev->filelist_mutex);
> > > > > +
> > > > > +	client->file = file;
> > > > > +
> > > > > +	mutex_unlock(&client->lock);
> > > > > +
> > > > > +	return 0;
> > > > > +
> > > > > +err_free:
> > > > > +	drm_file_free(file);
> > > > > +err_put:
> > > > > +	drm_dev_put(dev);
> > > > > +	module_put(dev->driver->fops->owner);
> > > > > +err_unlock:
> > > > > +	client->file_ref_count = 0;
> > > > > +	mutex_unlock(&client->lock);
> > > > > +
> > > > > +	return ret;
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_get_file);
> > > > > +
> > > > > +void drm_client_put_file(struct drm_client_dev *client)
> > > > > +{
> > > > > +	struct drm_device *dev = client->dev;
> > > > > +
> > > > > +	if (!client)
> > > > > +		return;
> > > > > +
> > > > > +	mutex_lock(&client->lock);
> > > > > +
> > > > > +	if (WARN_ON(!client->file_ref_count))
> > > > > +		goto out_unlock;
> > > > > +
> > > > > +	if (--client->file_ref_count)
> > > > > +		goto out_unlock;
> > > > > +
> > > > > +	mutex_lock(&dev->filelist_mutex);
> > > > > +	list_del(&client->file->lhead);
> > > > > +	mutex_unlock(&dev->filelist_mutex);
> > > > > +
> > > > > +	drm_file_free(client->file);
> > > > > +	client->file = NULL;
> > > > > +	drm_dev_put(dev);
> > > > > +	module_put(dev->driver->fops->owner);
> > > > > +out_unlock:
> > > > > +	mutex_unlock(&client->lock);
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_put_file);
> > > > > +
> > > > > +static struct drm_pending_event *
> > > > > +drm_client_read_get_pending_event(struct drm_device *dev, struct drm_file *file)
> > > > > +{
> > > > > +	struct drm_pending_event *e = NULL;
> > > > > +	int ret;
> > > > > +
> > > > > +	ret = mutex_lock_interruptible(&file->event_read_lock);
> > > > > +	if (ret)
> > > > > +		return ERR_PTR(ret);
> > > > > +
> > > > > +	spin_lock_irq(&dev->event_lock);
> > > > > +	if (!list_empty(&file->event_list)) {
> > > > > +		e = list_first_entry(&file->event_list,
> > > > > +				     struct drm_pending_event, link);
> > > > > +		file->event_space += e->event->length;
> > > > > +		list_del(&e->link);
> > > > > +	}
> > > > > +	spin_unlock_irq(&dev->event_lock);
> > > > > +
> > > > > +	mutex_unlock(&file->event_read_lock);
> > > > > +
> > > > > +	return e;
> > > > > +}
> > > > > +
> > > > > +struct drm_event *
> > > > > +drm_client_read_event(struct drm_client_dev *client, bool block)
> > > > > +{
> > > > > +	struct drm_file *file = client->file;
> > > > > +	struct drm_device *dev = client->dev;
> > > > > +	struct drm_pending_event *e;
> > > > > +	struct drm_event *event;
> > > > > +	int ret;
> > > > > +
> > > > > +	/* Allocate so it fits all events, there's a sanity check later */
> > > > > +	event = kzalloc(128, GFP_KERNEL);
> > > > > +	if (!event)
> > > > > +		return ERR_PTR(-ENOMEM);
> > > > > +
> > > > > +	e = drm_client_read_get_pending_event(dev, file);
> > > > > +	if (IS_ERR(e)) {
> > > > > +		ret = PTR_ERR(e);
> > > > > +		goto err_free;
> > > > > +	}
> > > > > +
> > > > > +	if (!e && !block) {
> > > > > +		ret = 0;
> > > > > +		goto err_free;
> > > > > +	}
> > > > > +
> > > > > +	ret = wait_event_interruptible_timeout(file->event_wait,
> > > > > +					       !list_empty(&file->event_list),
> > > > > +					       5 * HZ);
> > > > > +	if (!ret)
> > > > > +		ret = -ETIMEDOUT;
> > > > > +	if (ret < 0)
> > > > > +		goto err_free;
> > > > > +
> > > > > +	e = drm_client_read_get_pending_event(dev, file);
> > > > > +	if (IS_ERR_OR_NULL(e)) {
> > > > > +		ret = PTR_ERR_OR_ZERO(e);
> > > > > +		goto err_free;
> > > > > +	}
> > > > > +
> > > > > +	if (WARN_ON(e->event->length > 128)) {
> > > > > +		/* Increase buffer if this happens */
> > > > > +		ret = -ENOMEM;
> > > > > +		goto err_free;
> > > > > +	}
> > > > > +
> > > > > +	memcpy(event, e->event, e->event->length);
> > > > > +	kfree(e);
> > > > > +
> > > > > +	return event;
> > > > > +
> > > > > +err_free:
> > > > > +	kfree(event);
> > > > > +
> > > > > +	return ret ? ERR_PTR(ret) : NULL;
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_read_event);
> > > > > +
> > > > > +static void drm_client_connector_free(struct drm_client_connector *connector)
> > > > > +{
> > > > > +	if (!connector)
> > > > > +		return;
> > > > > +	kfree(connector->modes);
> > > > > +	kfree(connector);
> > > > > +}
> > > > > +
> > > > > +static struct drm_client_connector *
> > > > > +drm_client_get_connector(struct drm_client_dev *client, unsigned int id)
> > > > > +{
> > > > > +	struct drm_mode_get_connector req = {
> > > > > +		.connector_id = id,
> > > > > +	};
> > > > > +	struct drm_client_connector *connector;
> > > > > +	struct drm_mode_modeinfo *modes = NULL;
> > > > > +	struct drm_device *dev = client->dev;
> > > > > +	struct drm_connector *conn;
> > > > > +	bool non_desktop;
> > > > > +	int ret;
> > > > > +
> > > > > +	connector = kzalloc(sizeof(*connector), GFP_KERNEL);
> > > > > +	if (!connector)
> > > > > +		return ERR_PTR(-ENOMEM);
> > > > > +
> > > > > +	ret = drm_mode_getconnector(dev, &req, client->file, false);
> > > > > +	if (ret)
> > > > > +		goto err_free;
> > > > > +
> > > > > +	connector->conn_id = id;
> > > > > +	connector->status = req.connection;
> > > > > +
> > > > > +	conn = drm_connector_lookup(dev, client->file, id);
> > > > > +	if (!conn) {
> > > > > +		ret = -ENOENT;
> > > > > +		goto err_free;
> > > > > +	}
> > > > > +
> > > > > +	non_desktop = conn->display_info.non_desktop;
> > > > > +
> > > > > +	connector->has_tile = conn->has_tile;
> > > > > +	connector->tile_h_loc = conn->tile_h_loc;
> > > > > +	connector->tile_v_loc = conn->tile_v_loc;
> > > > > +	if (conn->tile_group)
> > > > > +		connector->tile_group = conn->tile_group->id;
> > > > > +
> > > > > +	drm_connector_put(conn);
> > > > > +
> > > > > +	if (non_desktop) {
> > > > > +		kfree(connector);
> > > > > +		return NULL;
> > > > > +	}
> > > > > +
> > > > > +	if (!req.count_modes)
> > > > > +		return connector;
> > > > > +
> > > > > +	modes = kcalloc(req.count_modes, sizeof(*modes), GFP_KERNEL);
> > > > > +	if (!modes) {
> > > > > +		ret = -ENOMEM;
> > > > > +		goto err_free;
> > > > > +	}
> > > > > +
> > > > > +	connector->modes = modes;
> > > > > +	connector->num_modes = req.count_modes;
> > > > > +
> > > > > +	req.count_props = 0;
> > > > > +	req.count_encoders = 0;
> > > > > +	req.modes_ptr = (unsigned long)modes;
> > > > > +
> > > > > +	ret = drm_mode_getconnector(dev, &req, client->file, false);
> > > > > +	if (ret)
> > > > > +		goto err_free;
> > > > > +
> > > > > +	return connector;
> > > > > +
> > > > > +err_free:
> > > > > +	kfree(modes);
> > > > > +	kfree(connector);
> > > > > +
> > > > > +	return ERR_PTR(ret);
> > > > > +}
> > > > > +
> > > > > +static int drm_client_get_connectors(struct drm_client_dev *client,
> > > > > +				     struct drm_client_connector ***connectors)
> > > > > +{
> > > > > +	struct drm_mode_card_res card_res = {};
> > > > > +	struct drm_device *dev = client->dev;
> > > > > +	int ret, num_connectors;
> > > > > +	u32 *connector_ids;
> > > > > +	unsigned int i;
> > > > > +
> > > > > +	ret = drm_mode_getresources(dev, &card_res, client->file, false);
> > > > > +	if (ret)
> > > > > +		return ret;
> > > > > +	if (!card_res.count_connectors)
> > > > > +		return 0;
> > > > > +
> > > > > +	num_connectors = card_res.count_connectors;
> > > > > +	connector_ids = kcalloc(num_connectors,
> > > > > +				sizeof(*connector_ids), GFP_KERNEL);
> > > > > +	if (!connector_ids)
> > > > > +		return -ENOMEM;
> > > > > +
> > > > > +	card_res.count_fbs = 0;
> > > > > +	card_res.count_crtcs = 0;
> > > > > +	card_res.count_encoders = 0;
> > > > > +	card_res.connector_id_ptr = (unsigned long)connector_ids;
> > > > > +
> > > > > +	ret = drm_mode_getresources(dev, &card_res, client->file, false);
> > > > > +	if (ret)
> > > > > +		goto err_free;
> > > > > +
> > > > > +	*connectors = kcalloc(num_connectors, sizeof(**connectors), GFP_KERNEL);
> > > > > +	if (!(*connectors)) {
> > > > > +		ret = -ENOMEM;
> > > > > +		goto err_free;
> > > > > +	}
> > > > > +
> > > > > +	for (i = 0; i < num_connectors; i++) {
> > > > > +		struct drm_client_connector *connector;
> > > > > +
> > > > > +		connector = drm_client_get_connector(client, connector_ids[i]);
> > > > > +		if (IS_ERR(connector)) {
> > > > > +			ret = PTR_ERR(connector);
> > > > > +			goto err_free;
> > > > > +		}
> > > > > +		if (connector)
> > > > > +			(*connectors)[i] = connector;
> > > > > +		else
> > > > > +			num_connectors--;
> > > > > +	}
> > > > > +
> > > > > +	if (!num_connectors) {
> > > > > +		ret = 0;
> > > > > +		goto err_free;
> > > > > +	}
> > > > > +
> > > > > +	return num_connectors;
> > > > > +
> > > > > +err_free:
> > > > > +	if (connectors)
> > > > > +		for (i = 0; i < num_connectors; i++)
> > > > > +			drm_client_connector_free((*connectors)[i]);
> > > > > +
> > > > > +	kfree(connectors);
> > > > > +	kfree(connector_ids);
> > > > > +
> > > > > +	return ret;
> > > > > +}
> > > > > +
> > > > > +static bool
> > > > > +drm_client_connector_is_enabled(struct drm_client_connector *connector,
> > > > > +				bool strict)
> > > > > +{
> > > > > +	if (strict)
> > > > > +		return connector->status == connector_status_connected;
> > > > > +	else
> > > > > +		return connector->status != connector_status_disconnected;
> > > > > +}
> > > > > +
> > > > > +struct drm_mode_modeinfo *
> > > > > +drm_client_display_first_mode(struct drm_client_display *display)
> > > > > +{
> > > > > +	if (!display->num_modes)
> > > > > +		return NULL;
> > > > > +	return display->modes;
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_display_first_mode);
> > > > > +
> > > > > +struct drm_mode_modeinfo *
> > > > > +drm_client_display_next_mode(struct drm_client_display *display,
> > > > > +			     struct drm_mode_modeinfo *mode)
> > > > > +{
> > > > > +	struct drm_mode_modeinfo *modes = display->modes;
> > > > > +
> > > > > +	if (++mode < &modes[display->num_modes])
> > > > > +		return mode;
> > > > > +
> > > > > +	return NULL;
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_display_next_mode);
> > > > > +
> > > > > +static void
> > > > > +drm_client_display_fill_tile_modes(struct drm_client_display *display,
> > > > > +				   struct drm_mode_modeinfo *tile_modes)
> > > > > +{
> > > > > +	unsigned int i, j, num_modes = display->connectors[0]->num_modes;
> > > > > +	struct drm_mode_modeinfo *tile_mode, *conn_mode;
> > > > > +
> > > > > +	if (!num_modes) {
> > > > > +		kfree(tile_modes);
> > > > > +		kfree(display->modes);
> > > > > +		display->modes = NULL;
> > > > > +		display->num_modes = 0;
> > > > > +		return;
> > > > > +	}
> > > > > +
> > > > > +	for (i = 0; i < num_modes; i++) {
> > > > > +		tile_mode = &tile_modes[i];
> > > > > +
> > > > > +		conn_mode = &display->connectors[0]->modes[i];
> > > > > +		tile_mode->clock = conn_mode->clock;
> > > > > +		tile_mode->vscan = conn_mode->vscan;
> > > > > +		tile_mode->vrefresh = conn_mode->vrefresh;
> > > > > +		tile_mode->flags = conn_mode->flags;
> > > > > +		tile_mode->type = conn_mode->type;
> > > > > +
> > > > > +		for (j = 0; j < display->num_connectors; j++) {
> > > > > +			conn_mode = &display->connectors[j]->modes[i];
> > > > > +
> > > > > +			if (!display->connectors[j]->tile_h_loc) {
> > > > > +				tile_mode->hdisplay += conn_mode->hdisplay;
> > > > > +				tile_mode->hsync_start += conn_mode->hsync_start;
> > > > > +				tile_mode->hsync_end += conn_mode->hsync_end;
> > > > > +				tile_mode->htotal += conn_mode->htotal;
> > > > > +			}
> > > > > +
> > > > > +			if (!display->connectors[j]->tile_v_loc) {
> > > > > +				tile_mode->vdisplay += conn_mode->vdisplay;
> > > > > +				tile_mode->vsync_start += conn_mode->vsync_start;
> > > > > +				tile_mode->vsync_end += conn_mode->vsync_end;
> > > > > +				tile_mode->vtotal += conn_mode->vtotal;
> > > > > +			}
> > > > > +		}
> > > > > +	}
> > > > > +
> > > > > +	kfree(display->modes);
> > > > > +	display->modes = tile_modes;
> > > > > +	display->num_modes = num_modes;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * drm_client_display_update_modes - Fetch display modes
> > > > > + * @display: Client display
> > > > > + * @mode_changed: Optional pointer to boolen which return whether the modes
> > > > > + *                have changed or not.
> > > > > + *
> > > > > + * This function can be used in the client hotplug callback to check if the
> > > > > + * video modes have changed and get them up-to-date.
> > > > > + *
> > > > > + * Returns:
> > > > > + * Number of modes on success, negative error code on failure.
> > > > > + */
> > > > > +int drm_client_display_update_modes(struct drm_client_display *display,
> > > > > +				    bool *mode_changed)
> > > > > +{
> > > > > +	unsigned int num_connectors = display->num_connectors;
> > > > > +	struct drm_client_dev *client = display->client;
> > > > > +	struct drm_mode_modeinfo *display_tile_modes;
> > > > > +	struct drm_client_connector **connectors;
> > > > > +	unsigned int i, num_modes = 0;
> > > > > +	bool dummy_changed = false;
> > > > > +	int ret;
> > > > > +
> > > > > +	if (mode_changed)
> > > > > +		*mode_changed = false;
> > > > > +	else
> > > > > +		mode_changed = &dummy_changed;
> > > > > +
> > > > > +	if (display->cloned)
> > > > > +		return 2;
> > > > > +
> > > > > +	ret = drm_client_get_file(client);
> > > > > +	if (ret)
> > > > > +		return ret;
> > > > > +
> > > > > +	connectors = kcalloc(num_connectors, sizeof(*connectors), GFP_KERNEL);
> > > > > +	if (!connectors) {
> > > > > +		ret = -ENOMEM;
> > > > > +		goto out_put_file;
> > > > > +	}
> > > > > +
> > > > > +	/* Get a new set for comparison */
> > > > > +	for (i = 0; i < num_connectors; i++) {
> > > > > +		connectors[i] = drm_client_get_connector(client, display->connectors[i]->conn_id);
> > > > > +		if (IS_ERR_OR_NULL(connectors[i])) {
> > > > > +			ret = PTR_ERR_OR_ZERO(connectors[i]);
> > > > > +			if (!ret)
> > > > > +				ret = -ENOENT;
> > > > > +			goto out_cleanup;
> > > > > +		}
> > > > > +	}
> > > > > +
> > > > > +	/* All connectors should have the same number of modes */
> > > > > +	num_modes = connectors[0]->num_modes;
> > > > > +	for (i = 0; i < num_connectors; i++) {
> > > > > +		if (num_modes != connectors[i]->num_modes) {
> > > > > +			ret = -EINVAL;
> > > > > +			goto out_cleanup;
> > > > > +		}
> > > > > +	}
> > > > > +
> > > > > +	if (num_connectors > 1) {
> > > > > +		display_tile_modes = kcalloc(num_modes, sizeof(*display_tile_modes), GFP_KERNEL);
> > > > > +		if (!display_tile_modes) {
> > > > > +			ret = -ENOMEM;
> > > > > +			goto out_cleanup;
> > > > > +		}
> > > > > +	}
> > > > > +
> > > > > +	mutex_lock(&display->modes_lock);
> > > > > +
> > > > > +	for (i = 0; i < num_connectors; i++) {
> > > > > +		display->connectors[i]->status = connectors[i]->status;
> > > > > +		if (display->connectors[i]->num_modes != connectors[i]->num_modes) {
> > > > > +			display->connectors[i]->num_modes = connectors[i]->num_modes;
> > > > > +			kfree(display->connectors[i]->modes);
> > > > > +			display->connectors[i]->modes = connectors[i]->modes;
> > > > > +			connectors[i]->modes = NULL;
> > > > > +			*mode_changed = true;
> > > > > +		}
> > > > > +	}
> > > > > +
> > > > > +	if (num_connectors > 1)
> > > > > +		drm_client_display_fill_tile_modes(display, display_tile_modes);
> > > > > +	else
> > > > > +		display->modes = display->connectors[0]->modes;
> > > > > +
> > > > > +	mutex_unlock(&display->modes_lock);
> > > > > +
> > > > > +out_cleanup:
> > > > > +	for (i = 0; i < num_connectors; i++)
> > > > > +		drm_client_connector_free(connectors[i]);
> > > > > +	kfree(connectors);
> > > > > +out_put_file:
> > > > > +	drm_client_put_file(client);
> > > > > +
> > > > > +	return ret ? ret : num_modes;
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_display_update_modes);
> > > > > +
> > > > > +void drm_client_display_free(struct drm_client_display *display)
> > > > > +{
> > > > > +	unsigned int i;
> > > > > +
> > > > > +	if (!display)
> > > > > +		return;
> > > > > +
> > > > > +	/* tile modes? */
> > > > > +	if (display->modes != display->connectors[0]->modes)
> > > > > +		kfree(display->modes);
> > > > > +
> > > > > +	for (i = 0; i < display->num_connectors; i++)
> > > > > +		drm_client_connector_free(display->connectors[i]);
> > > > > +
> > > > > +	kfree(display->connectors);
> > > > > +	mutex_destroy(&display->modes_lock);
> > > > > +	kfree(display);
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_display_free);
> > > > > +
> > > > > +static struct drm_client_display *
> > > > > +drm_client_display_alloc(struct drm_client_dev *client,
> > > > > +			 unsigned int num_connectors)
> > > > > +{
> > > > > +	struct drm_client_display *display;
> > > > > +	struct drm_client_connector **connectors;
> > > > > +
> > > > > +	display = kzalloc(sizeof(*display), GFP_KERNEL);
> > > > > +	connectors = kcalloc(num_connectors, sizeof(*connectors), GFP_KERNEL);
> > > > > +	if (!display || !connectors) {
> > > > > +		kfree(display);
> > > > > +		kfree(connectors);
> > > > > +		return NULL;
> > > > > +	}
> > > > > +
> > > > > +	mutex_init(&display->modes_lock);
> > > > > +	display->client = client;
> > > > > +	display->connectors = connectors;
> > > > > +	display->num_connectors = num_connectors;
> > > > > +
> > > > > +	return display;
> > > > > +}
> > > > > +
> > > > > +/* Logic is from drm_fb_helper */
> > > > > +static struct drm_client_display *
> > > > > +drm_client_connector_pick_cloned(struct drm_client_dev *client,
> > > > > +				 struct drm_client_connector **connectors,
> > > > > +				 unsigned int num_connectors)
> > > > > +{
> > > > > +	struct drm_mode_modeinfo modes[2], udmt_mode, *mode, *tmp;
> > > > > +	struct drm_display_mode *dmt_display_mode = NULL;
> > > > > +	unsigned int i, j, conns[2], num_conns = 0;
> > > > > +	struct drm_client_connector *connector;
> > > > > +	struct drm_device *dev = client->dev;
> > > > > +	struct drm_client_display *display;
> > > > > +
> > > > > +	/* only contemplate cloning in the single crtc case */
> > > > > +	if (dev->mode_config.num_crtc > 1)
> > > > > +		return NULL;
> > > > > +retry:
> > > > > +	for (i = 0; i < num_connectors; i++) {
> > > > > +		connector = connectors[i];
> > > > > +		if (!connector || connector->has_tile || !connector->num_modes)
> > > > > +			continue;
> > > > > +
> > > > > +		for (j = 0; j < connector->num_modes; j++) {
> > > > > +			mode = &connector->modes[j];
> > > > > +			if (dmt_display_mode) {
> > > > > +				if (drm_umode_equal(&udmt_mode, mode)) {
> > > > > +					conns[num_conns] = i;
> > > > > +					modes[num_conns++] = *mode;
> > > > > +					break;
> > > > > +				}
> > > > > +			} else {
> > > > > +				if (mode->type & DRM_MODE_TYPE_USERDEF) {
> > > > > +					conns[num_conns] = i;
> > > > > +					modes[num_conns++] = *mode;
> > > > > +					break;
> > > > > +				}
> > > > > +			}
> > > > > +		}
> > > > > +		if (num_conns == 2)
> > > > > +			break;
> > > > > +	}
> > > > > +
> > > > > +	if (num_conns == 2)
> > > > > +		goto found;
> > > > > +
> > > > > +	if (dmt_display_mode)
> > > > > +		return NULL;
> > > > > +
> > > > > +	dmt_display_mode = drm_mode_find_dmt(dev, 1024, 768, 60, false);
> > > > > +	drm_mode_convert_to_umode(&udmt_mode, dmt_display_mode);
> > > > > +	drm_mode_destroy(dev, dmt_display_mode);
> > > > > +
> > > > > +	goto retry;
> > > > > +
> > > > > +found:
> > > > > +	tmp = kcalloc(2, sizeof(*tmp), GFP_KERNEL);
> > > > > +	if (!tmp)
> > > > > +		return ERR_PTR(-ENOMEM);
> > > > > +
> > > > > +	display = drm_client_display_alloc(client, 2);
> > > > > +	if (!display) {
> > > > > +		kfree(tmp);
> > > > > +		return ERR_PTR(-ENOMEM);
> > > > > +	}
> > > > > +
> > > > > +	for (i = 0; i < 2; i++) {
> > > > > +		connector = connectors[conns[i]];
> > > > > +		display->connectors[i] = connector;
> > > > > +		connectors[conns[i]] = NULL;
> > > > > +		kfree(connector->modes);
> > > > > +		tmp[i] = modes[i];
> > > > > +		connector->modes = &tmp[i];
> > > > > +		connector->num_modes = 1;
> > > > > +	}
> > > > > +
> > > > > +	display->cloned = true;
> > > > > +	display->modes = &tmp[0];
> > > > > +	display->num_modes = 1;
> > > > > +
> > > > > +	return display;
> > > > > +}
> > > > > +
> > > > > +static struct drm_client_display *
> > > > > +drm_client_connector_pick_tile(struct drm_client_dev *client,
> > > > > +			       struct drm_client_connector **connectors,
> > > > > +			       unsigned int num_connectors)
> > > > > +{
> > > > > +	unsigned int i, num_conns, num_modes, tile_group = 0;
> > > > > +	struct drm_mode_modeinfo *tile_modes = NULL;
> > > > > +	struct drm_client_connector *connector;
> > > > > +	struct drm_client_display *display;
> > > > > +	u16 conns[32];
> > > > > +
> > > > > +	for (i = 0; i < num_connectors; i++) {
> > > > > +		connector = connectors[i];
> > > > > +		if (!connector || !connector->tile_group)
> > > > > +			continue;
> > > > > +
> > > > > +		if (!tile_group) {
> > > > > +			tile_group = connector->tile_group;
> > > > > +			num_modes = connector->num_modes;
> > > > > +		}
> > > > > +
> > > > > +		if (connector->tile_group != tile_group)
> > > > > +			continue;
> > > > > +
> > > > > +		if (num_modes != connector->num_modes) {
> > > > > +			DRM_ERROR("Tile connectors must have the same number of modes\n");
> > > > > +			return ERR_PTR(-EINVAL);
> > > > > +		}
> > > > > +
> > > > > +		conns[num_conns++] = i;
> > > > > +		if (WARN_ON(num_conns == 33))
> > > > > +			return ERR_PTR(-EINVAL);
> > > > > +	}
> > > > > +
> > > > > +	if (!num_conns)
> > > > > +		return NULL;
> > > > > +
> > > > > +	if (num_modes) {
> > > > > +		tile_modes = kcalloc(num_modes, sizeof(*tile_modes), GFP_KERNEL);
> > > > > +		if (!tile_modes)
> > > > > +			return ERR_PTR(-ENOMEM);
> > > > > +	}
> > > > > +
> > > > > +	display = drm_client_display_alloc(client, num_conns);
> > > > > +	if (!display) {
> > > > > +		kfree(tile_modes);
> > > > > +		return ERR_PTR(-ENOMEM);
> > > > > +	}
> > > > > +
> > > > > +	if (num_modes)
> > > > > +		drm_client_display_fill_tile_modes(display, tile_modes);
> > > > > +
> > > > > +	return display;
> > > > > +}
> > > > > +
> > > > > +static struct drm_client_display *
> > > > > +drm_client_connector_pick_not_tile(struct drm_client_dev *client,
> > > > > +				   struct drm_client_connector **connectors,
> > > > > +				   unsigned int num_connectors)
> > > > > +{
> > > > > +	struct drm_client_display *display;
> > > > > +	unsigned int i;
> > > > > +
> > > > > +	for (i = 0; i < num_connectors; i++) {
> > > > > +		if (!connectors[i] || connectors[i]->has_tile)
> > > > > +			continue;
> > > > > +		break;
> > > > > +	}
> > > > > +
> > > > > +	if (i == num_connectors)
> > > > > +		return NULL;
> > > > > +
> > > > > +	display = drm_client_display_alloc(client, 1);
> > > > > +	if (!display)
> > > > > +		return ERR_PTR(-ENOMEM);
> > > > > +
> > > > > +	display->connectors[0] = connectors[i];
> > > > > +	connectors[i] = NULL;
> > > > > +	display->modes = display->connectors[0]->modes;
> > > > > +	display->num_modes = display->connectors[0]->num_modes;
> > > > > +
> > > > > +	return display;
> > > > > +}
> > > > > +
> > > > > +/* Get connectors and bundle them up into displays */
> > > > > +static int drm_client_get_displays(struct drm_client_dev *client,
> > > > > +				   struct drm_client_display ***displays)
> > > > > +{
> > > > > +	int ret, num_connectors, num_displays = 0;
> > > > > +	struct drm_client_connector **connectors;
> > > > > +	struct drm_client_display *display;
> > > > > +	unsigned int i;
> > > > > +
> > > > > +	ret = drm_client_get_file(client);
> > > > > +	if (ret)
> > > > > +		return ret;
> > > > > +
> > > > > +	num_connectors = drm_client_get_connectors(client, &connectors);
> > > > > +	if (num_connectors <= 0) {
> > > > > +		ret = num_connectors;
> > > > > +		goto err_put_file;
> > > > > +	}
> > > > > +
> > > > > +	*displays = kcalloc(num_connectors, sizeof(*displays), GFP_KERNEL);
> > > > > +	if (!(*displays)) {
> > > > > +		ret = -ENOMEM;
> > > > > +		goto err_free;
> > > > > +	}
> > > > > +
> > > > > +	display = drm_client_connector_pick_cloned(client, connectors,
> > > > > +						   num_connectors);
> > > > > +	if (IS_ERR(display)) {
> > > > > +		ret = PTR_ERR(display);
> > > > > +		goto err_free;
> > > > > +	}
> > > > > +	if (display)
> > > > > +		(*displays)[num_displays++] = display;
> > > > > +
> > > > > +	for (i = 0; i < num_connectors; i++) {
> > > > > +		display = drm_client_connector_pick_tile(client, connectors,
> > > > > +							 num_connectors);
> > > > > +		if (IS_ERR(display)) {
> > > > > +			ret = PTR_ERR(display);
> > > > > +			goto err_free;
> > > > > +		}
> > > > > +		if (!display)
> > > > > +			break;
> > > > > +		(*displays)[num_displays++] = display;
> > > > > +	}
> > > > > +
> > > > > +	for (i = 0; i < num_connectors; i++) {
> > > > > +		display = drm_client_connector_pick_not_tile(client, connectors,
> > > > > +							     num_connectors);
> > > > > +		if (IS_ERR(display)) {
> > > > > +			ret = PTR_ERR(display);
> > > > > +			goto err_free;
> > > > > +		}
> > > > > +		if (!display)
> > > > > +			break;
> > > > > +		(*displays)[num_displays++] = display;
> > > > > +	}
> > > > > +
> > > > > +	for (i = 0; i < num_connectors; i++) {
> > > > > +		if (connectors[i]) {
> > > > > +			DRM_INFO("Connector %u fell through the cracks.\n",
> > > > > +				 connectors[i]->conn_id);
> > > > > +			drm_client_connector_free(connectors[i]);
> > > > > +		}
> > > > > +	}
> > > > > +
> > > > > +	drm_client_put_file(client);
> > > > > +	kfree(connectors);
> > > > > +
> > > > > +	return num_displays;
> > > > > +
> > > > > +err_free:
> > > > > +	for (i = 0; i < num_displays; i++)
> > > > > +		drm_client_display_free((*displays)[i]);
> > > > > +	kfree(*displays);
> > > > > +	*displays = NULL;
> > > > > +	for (i = 0; i < num_connectors; i++)
> > > > > +		drm_client_connector_free(connectors[i]);
> > > > > +	kfree(connectors);
> > > > > +err_put_file:
> > > > > +	drm_client_put_file(client);
> > > > > +
> > > > > +	return ret;
> > > > > +}
> > > > > +
> > > > > +static bool
> > > > > +drm_client_display_is_enabled(struct drm_client_display *display, bool strict)
> > > > > +{
> > > > > +	unsigned int i;
> > > > > +
> > > > > +	if (!display->num_modes)
> > > > > +		return false;
> > > > > +
> > > > > +	for (i = 0; i < display->num_connectors; i++)
> > > > > +		if (!drm_client_connector_is_enabled(display->connectors[i], strict))
> > > > > +			return false;
> > > > > +
> > > > > +	return true;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * drm_client_display_get_first_enabled - Get first enabled display
> > > > > + * @client: DRM client
> > > > > + * @strict: If true the connector(s) have to be connected, if false they can
> > > > > + *          also have unknown status.
> > > > > + *
> > > > > + * This function gets all connectors and bundles them into displays
> > > > > + * (tiled/cloned). It then picks the first one with connectors that is enabled
> > > > > + * according to @strict.
> > > > > + *
> > > > > + * Returns:
> > > > > + * Pointer to a client display if such a display was found, NULL if not found
> > > > > + * or an error pointer on failure.
> > > > > + */
> > > > > +struct drm_client_display *
> > > > > +drm_client_display_get_first_enabled(struct drm_client_dev *client, bool strict)
> > > > > +{
> > > > > +	struct drm_client_display **displays, *display = NULL;
> > > > > +	int num_displays;
> > > > > +	unsigned int i;
> > > > > +
> > > > > +	num_displays = drm_client_get_displays(client, &displays);
> > > > > +	if (num_displays < 0)
> > > > > +		return ERR_PTR(num_displays);
> > > > > +	if (!num_displays)
> > > > > +		return NULL;
> > > > > +
> > > > > +	for (i = 0; i < num_displays; i++) {
> > > > > +		if (!display &&
> > > > > +		    drm_client_display_is_enabled(displays[i], strict)) {
> > > > > +			display = displays[i];
> > > > > +			continue;
> > > > > +		}
> > > > > +		drm_client_display_free(displays[i]);
> > > > > +	}
> > > > > +
> > > > > +	kfree(displays);
> > > > > +
> > > > > +	return display;
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_display_get_first_enabled);
> > > > > +
> > > > > +unsigned int
> > > > > +drm_client_display_preferred_depth(struct drm_client_display *display)
> > > > > +{
> > > > > +	struct drm_connector *conn;
> > > > > +	unsigned int ret;
> > > > > +
> > > > > +	conn = drm_connector_lookup(display->client->dev, NULL,
> > > > > +				    display->connectors[0]->conn_id);
> > > > > +	if (!conn)
> > > > > +		return 0;
> > > > > +
> > > > > +	if (conn->cmdline_mode.bpp_specified)
> > > > > +		ret = conn->cmdline_mode.bpp;
> > > > > +	else
> > > > > +		ret = display->client->dev->mode_config.preferred_depth;
> > > > > +
> > > > > +	drm_connector_put(conn);
> > > > > +
> > > > > +	return ret;
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_display_preferred_depth);
> > > > > +
> > > > > +int drm_client_display_dpms(struct drm_client_display *display, int mode)
> > > > > +{
> > > > > +	struct drm_mode_obj_set_property prop;
> > > > > +
> > > > > +	prop.value = mode;
> > > > > +	prop.prop_id = display->client->dev->mode_config.dpms_property->base.id;
> > > > > +	prop.obj_id = display->connectors[0]->conn_id;
> > > > > +	prop.obj_type = DRM_MODE_OBJECT_CONNECTOR;
> > > > > +
> > > > > +	return drm_mode_obj_set_property(display->client->dev, &prop,
> > > > > +					 display->client->file);
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_display_dpms);
> > > > > +
> > > > > +int drm_client_display_wait_vblank(struct drm_client_display *display)
> > > > > +{
> > > > > +	struct drm_crtc *crtc;
> > > > > +	union drm_wait_vblank vblank_req = {
> > > > > +		.request = {
> > > > > +			.type = _DRM_VBLANK_RELATIVE,
> > > > > +			.sequence = 1,
> > > > > +		},
> > > > > +	};
> > > > > +
> > > > > +	crtc = drm_crtc_find(display->client->dev, display->client->file,
> > > > > +			     display->connectors[0]->crtc_id);
> > > > > +	if (!crtc)
> > > > > +		return -ENOENT;
> > > > > +
> > > > > +	vblank_req.request.type |= drm_crtc_index(crtc) << _DRM_VBLANK_HIGH_CRTC_SHIFT;
> > > > > +
> > > > > +	return drm_wait_vblank(display->client->dev, &vblank_req,
> > > > > +			       display->client->file);
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_display_wait_vblank);
> > > > > +
> > > > > +static int drm_client_get_crtc_index(struct drm_client_dev *client, u32 id)
> > > > > +{
> > > > > +	int i;
> > > > > +
> > > > > +	for (i = 0; i < client->num_crtcs; i++)
> > > > > +		if (client->crtcs[i] == id)
> > > > > +			return i;
> > > > > +
> > > > > +	return -ENOENT;
> > > > > +}
> > > > > +
> > > > > +static int drm_client_display_find_crtcs(struct drm_client_display *display)
> > > > > +{
> > > > > +	struct drm_client_dev *client = display->client;
> > > > > +	struct drm_device *dev = client->dev;
> > > > > +	struct drm_file *file = client->file;
> > > > > +	u32 encoder_ids[DRM_CONNECTOR_MAX_ENCODER];
> > > > > +	unsigned int i, j, available_crtcs = ~0;
> > > > > +	struct drm_mode_get_connector conn_req;
> > > > > +	struct drm_mode_get_encoder enc_req;
> > > > > +	int ret;
> > > > > +
> > > > > +	/* Already done? */
> > > > > +	if (display->connectors[0]->crtc_id)
> > > > > +		return 0;
> > > > > +
> > > > > +	for (i = 0; i < display->num_connectors; i++) {
> > > > > +		u32 active_crtcs = 0, crtcs_for_connector = 0;
> > > > > +		int crtc_idx;
> > > > > +
> > > > > +		memset(&conn_req, 0, sizeof(conn_req));
> > > > > +		conn_req.connector_id = display->connectors[i]->conn_id;
> > > > > +		conn_req.encoders_ptr = (unsigned long)(encoder_ids);
> > > > > +		conn_req.count_encoders = DRM_CONNECTOR_MAX_ENCODER;
> > > > > +		ret = drm_mode_getconnector(dev, &conn_req, file, false);
> > > > > +		if (ret)
> > > > > +			return ret;
> > > > > +
> > > > > +		if (conn_req.encoder_id) {
> > > > > +			memset(&enc_req, 0, sizeof(enc_req));
> > > > > +			enc_req.encoder_id = conn_req.encoder_id;
> > > > > +			ret = drm_mode_getencoder(dev, &enc_req, file);
> > > > > +			if (ret)
> > > > > +				return ret;
> > > > > +			crtcs_for_connector |= enc_req.possible_crtcs;
> > > > > +			if (crtcs_for_connector & available_crtcs)
> > > > > +				goto found;
> > > > > +		}
> > > > > +
> > > > > +		for (j = 0; j < conn_req.count_encoders; j++) {
> > > > > +			memset(&enc_req, 0, sizeof(enc_req));
> > > > > +			enc_req.encoder_id = encoder_ids[j];
> > > > > +			ret = drm_mode_getencoder(dev, &enc_req, file);
> > > > > +			if (ret)
> > > > > +				return ret;
> > > > > +
> > > > > +			crtcs_for_connector |= enc_req.possible_crtcs;
> > > > > +
> > > > > +			if (enc_req.crtc_id) {
> > > > > +				crtc_idx = drm_client_get_crtc_index(client, enc_req.crtc_id);
> > > > > +				if (crtc_idx >= 0)
> > > > > +					active_crtcs |= 1 << crtc_idx;
> > > > > +			}
> > > > > +		}
> > > > > +
> > > > > +found:
> > > > > +		crtcs_for_connector &= available_crtcs;
> > > > > +		active_crtcs &= available_crtcs;
> > > > > +
> > > > > +		if (!crtcs_for_connector)
> > > > > +			return -ENOENT;
> > > > > +
> > > > > +		if (active_crtcs)
> > > > > +			crtc_idx = ffs(active_crtcs) - 1;
> > > > > +		else
> > > > > +			crtc_idx = ffs(crtcs_for_connector) - 1;
> > > > > +
> > > > > +		if (crtc_idx >= client->num_crtcs)
> > > > > +			return -EINVAL;
> > > > > +
> > > > > +		display->connectors[i]->crtc_id = client->crtcs[crtc_idx];
> > > > > +		available_crtcs &= ~BIT(crtc_idx);
> > > > > +	}
> > > > > +
> > > > > +	return 0;
> > > > > +}
> > > > > +
> > > > > +/**
> > > > > + * drm_client_display_commit_mode - Commit a mode to the crtc(s)
> > > > > + * @display: Client display
> > > > > + * @fb_id: Framebuffer id
> > > > > + * @mode: Video mode
> > > > > + *
> > > > > + * Returns:
> > > > > + * Zero on success, negative error code on failure.
> > > > > + */
> > > > > +int drm_client_display_commit_mode(struct drm_client_display *display,
> > > > > +				   u32 fb_id, struct drm_mode_modeinfo *mode)
> > > > > +{
> > > > > +	struct drm_client_dev *client = display->client;
> > > > > +	struct drm_device *dev = client->dev;
> > > > > +	unsigned int num_crtcs = client->num_crtcs;
> > > > > +	struct drm_file *file = client->file;
> > > > > +	unsigned int *xoffsets = NULL, *yoffsets = NULL;
> > > > > +	struct drm_mode_crtc *crtc_reqs, *req;
> > > > > +	u32 cloned_conn_ids[2];
> > > > > +	unsigned int i;
> > > > > +	int idx, ret;
> > > > > +
> > > > > +	ret = drm_client_display_find_crtcs(display);
> > > > > +	if (ret)
> > > > > +		return ret;
> > > > > +
> > > > > +	crtc_reqs = kcalloc(num_crtcs, sizeof(*crtc_reqs), GFP_KERNEL);
> > > > > +	if (!crtc_reqs)
> > > > > +		return -ENOMEM;
> > > > > +
> > > > > +	for (i = 0; i < num_crtcs; i++)
> > > > > +		crtc_reqs[i].crtc_id = client->crtcs[i];
> > > > > +
> > > > > +	if (drm_client_display_is_tiled(display)) {
> > > > > +		/* TODO calculate tile crtc offsets */
> > > > > +	}
> > > > > +
> > > > > +	for (i = 0; i < display->num_connectors; i++) {
> > > > > +		idx = drm_client_get_crtc_index(client, display->connectors[i]->crtc_id);
> > > > > +		if (idx < 0)
> > > > > +			return -ENOENT;
> > > > > +
> > > > > +		req = &crtc_reqs[idx];
> > > > > +
> > > > > +		req->fb_id = fb_id;
> > > > > +		if (xoffsets) {
> > > > > +			req->x = xoffsets[i];
> > > > > +			req->y = yoffsets[i];
> > > > > +		}
> > > > > +		req->mode_valid = 1;
> > > > > +		req->mode = *mode;
> > > > > +
> > > > > +		if (display->cloned) {
> > > > > +			cloned_conn_ids[0] = display->connectors[0]->conn_id;
> > > > > +			cloned_conn_ids[1] = display->connectors[1]->conn_id;
> > > > > +			req->set_connectors_ptr = (unsigned long)(cloned_conn_ids);
> > > > > +			req->count_connectors = 2;
> > > > > +			break;
> > > > > +		}
> > > > > +
> > > > > +		req->set_connectors_ptr = (unsigned long)(&display->connectors[i]->conn_id);
> > > > > +		req->count_connectors = 1;
> > > > > +	}
> > > > > +
> > > > > +	for (i = 0; i < num_crtcs; i++) {
> > > > > +		ret = drm_mode_setcrtc(dev, &crtc_reqs[i], file, false);
> > > > > +		if (ret)
> > > > > +			break;
> > > > > +	}
> > > > > +
> > > > > +	kfree(xoffsets);
> > > > > +	kfree(yoffsets);
> > > > > +	kfree(crtc_reqs);
> > > > > +
> > > > > +	return ret;
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_display_commit_mode);
> > > > > +
> > > > > +unsigned int drm_client_display_current_fb(struct drm_client_display *display)
> > > > > +{
> > > > > +	struct drm_client_dev *client = display->client;
> > > > > +	int ret;
> > > > > +	struct drm_mode_crtc crtc_req = {
> > > > > +		.crtc_id = display->connectors[0]->crtc_id,
> > > > > +	};
> > > > > +
> > > > > +	ret = drm_mode_getcrtc(client->dev, &crtc_req, client->file);
> > > > > +	if (ret)
> > > > > +		return 0;
> > > > > +
> > > > > +	return crtc_req.fb_id;
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_display_current_fb);
> > > > > +
> > > > > +int drm_client_display_flush(struct drm_client_display *display, u32 fb_id,
> > > > > +			     struct drm_clip_rect *clips, unsigned int num_clips)
> > > > > +{
> > > > > +	struct drm_client_dev *client = display->client;
> > > > > +	struct drm_mode_fb_dirty_cmd dirty_req = {
> > > > > +		.fb_id = fb_id,
> > > > > +		.clips_ptr = (unsigned long)clips,
> > > > > +		.num_clips = num_clips,
> > > > > +	};
> > > > > +	int ret;
> > > > > +
> > > > > +	if (display->no_flushing)
> > > > > +		return 0;
> > > > > +
> > > > > +	ret = drm_mode_dirtyfb(client->dev, &dirty_req, client->file, false);
> > > > > +	if (ret == -ENOSYS) {
> > > > > +		ret = 0;
> > > > > +		display->no_flushing = true;
> > > > > +	}
> > > > > +
> > > > > +	return ret;
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_display_flush);
> > > > > +
> > > > > +int drm_client_display_page_flip(struct drm_client_display *display, u32 fb_id,
> > > > > +				 bool event)
> > > > > +{
> > > > > +	struct drm_client_dev *client = display->client;
> > > > > +	struct drm_mode_crtc_page_flip_target page_flip_req = {
> > > > > +		.crtc_id = display->connectors[0]->crtc_id,
> > > > > +		.fb_id = fb_id,
> > > > > +	};
> > > > > +
> > > > > +	if (event)
> > > > > +		page_flip_req.flags = DRM_MODE_PAGE_FLIP_EVENT;
> > > > > +
> > > > > +	return drm_mode_page_flip(client->dev, &page_flip_req, client->file);
> > > > > +	/*
> > > > > +	 * TODO:
> > > > > +	 * Where do we flush on page flip? Should the driver handle that?
> > > > > +	 */
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_display_page_flip);
> > > > > +
> > > > > +/**
> > > > > + * drm_client_framebuffer_create - Create a client framebuffer
> > > > > + * @client: DRM client
> > > > > + * @mode: Display mode to create a buffer for
> > > > > + * @format: Buffer format
> > > > > + *
> > > > > + * This function creates a &drm_client_buffer which consists of a
> > > > > + * &drm_framebuffer backed by a dumb buffer. The dumb buffer is &dma_buf
> > > > > + * exported to aquire a virtual address which is stored in
> > > > > + * &drm_client_buffer->vaddr.
> > > > > + * Call drm_client_framebuffer_delete() to free the buffer.
> > > > > + *
> > > > > + * Returns:
> > > > > + * Pointer to a client buffer or an error pointer on failure.
> > > > > + */
> > > > > +struct drm_client_buffer *
> > > > > +drm_client_framebuffer_create(struct drm_client_dev *client,
> > > > > +			      struct drm_mode_modeinfo *mode, u32 format)
> > > > > +{
> > > > > +	struct drm_client_buffer *buffer;
> > > > > +	int ret;
> > > > > +
> > > > > +	buffer = drm_client_buffer_create(client, mode->hdisplay,
> > > > > +					  mode->vdisplay, format);
> > > > > +	if (IS_ERR(buffer))
> > > > > +		return buffer;
> > > > > +
> > > > > +	ret = drm_client_buffer_addfb(buffer, mode);
> > > > > +	if (ret) {
> > > > > +		drm_client_buffer_delete(buffer);
> > > > > +		return ERR_PTR(ret);
> > > > > +	}
> > > > > +
> > > > > +	return buffer;
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_framebuffer_create);
> > > > > +
> > > > > +void drm_client_framebuffer_delete(struct drm_client_buffer *buffer)
> > > > > +{
> > > > > +	drm_client_buffer_rmfb(buffer);
> > > > > +	drm_client_buffer_delete(buffer);
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_framebuffer_delete);
> > > > > +
> > > > > +struct drm_client_buffer *
> > > > > +drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height,
> > > > > +			 u32 format)
> > > > > +{
> > > > > +	struct drm_mode_create_dumb dumb_args = { 0 };
> > > > > +	struct drm_prime_handle prime_args = { 0 };
> > > > > +	struct drm_client_buffer *buffer;
> > > > > +	struct dma_buf *dma_buf;
> > > > > +	void *vaddr;
> > > > > +	int ret;
> > > > > +
> > > > > +	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
> > > > > +	if (!buffer)
> > > > > +		return ERR_PTR(-ENOMEM);
> > > > > +
> > > > > +	ret = drm_client_get_file(client);
> > > > > +	if (ret)
> > > > > +		goto err_free;
> > > > > +
> > > > > +	buffer->client = client;
> > > > > +	buffer->width = width;
> > > > > +	buffer->height = height;
> > > > > +	buffer->format = format;
> > > > > +
> > > > > +	dumb_args.width = buffer->width;
> > > > > +	dumb_args.height = buffer->height;
> > > > > +	dumb_args.bpp = drm_format_plane_cpp(format, 0) * 8;
> > > > > +	ret = drm_mode_create_dumb(client->dev, &dumb_args, client->file);
> > > > > +	if (ret)
> > > > > +		goto err_put_file;
> > > > > +
> > > > > +	buffer->handle = dumb_args.handle;
> > > > > +	buffer->pitch = dumb_args.pitch;
> > > > > +	buffer->size = dumb_args.size;
> > > > > +
> > > > > +	prime_args.handle = dumb_args.handle;
> > > > > +	ret = drm_prime_handle_to_fd(client->dev, &prime_args, client->file);
> > > > > +	if (ret)
> > > > > +		goto err_delete;
> > > > > +
> > > > > +	dma_buf = dma_buf_get(prime_args.fd);
> > > > > +	if (IS_ERR(dma_buf)) {
> > > > > +		ret = PTR_ERR(dma_buf);
> > > > > +		goto err_delete;
> > > > > +	}
> > > > > +
> > > > > +	buffer->dma_buf = dma_buf;
> > > > > +
> > > > > +	vaddr = dma_buf_vmap(dma_buf);
> > > > > +	if (!vaddr) {
> > > > > +		ret = -ENOMEM;
> > > > > +		goto err_delete;
> > > > > +	}
> > > > > +
> > > > > +	buffer->vaddr = vaddr;
> > > > > +
> > > > > +	return buffer;
> > > > > +
> > > > > +err_delete:
> > > > > +	drm_client_buffer_delete(buffer);
> > > > > +err_put_file:
> > > > > +	drm_client_put_file(client);
> > > > > +err_free:
> > > > > +	kfree(buffer);
> > > > > +
> > > > > +	return ERR_PTR(ret);
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_buffer_create);
> > > > > +
> > > > > +void drm_client_buffer_delete(struct drm_client_buffer *buffer)
> > > > > +{
> > > > > +	if (!buffer)
> > > > > +		return;
> > > > > +
> > > > > +	if (buffer->vaddr)
> > > > > +		dma_buf_vunmap(buffer->dma_buf, buffer->vaddr);
> > > > > +
> > > > > +	if (buffer->dma_buf)
> > > > > +		dma_buf_put(buffer->dma_buf);
> > > > > +
> > > > > +	drm_mode_destroy_dumb(buffer->client->dev, buffer->handle,
> > > > > +			      buffer->client->file);
> > > > > +	drm_client_put_file(buffer->client);
> > > > > +	kfree(buffer);
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_buffer_delete);
> > > > > +
> > > > > +int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
> > > > > +			    struct drm_mode_modeinfo *mode)
> > > > > +{
> > > > > +	struct drm_client_dev *client = buffer->client;
> > > > > +	struct drm_mode_fb_cmd2 fb_req = { };
> > > > > +	unsigned int num_fbs, *fb_ids;
> > > > > +	int i, ret;
> > > > > +
> > > > > +	if (buffer->num_fbs)
> > > > > +		return -EINVAL;
> > > > > +
> > > > > +	if (mode->hdisplay > buffer->width || mode->vdisplay > buffer->height)
> > > > > +		return -EINVAL;
> > > > > +
> > > > > +	num_fbs = buffer->height / mode->vdisplay;
> > > > > +	fb_ids = kcalloc(num_fbs, sizeof(*fb_ids), GFP_KERNEL);
> > > > > +	if (!fb_ids)
> > > > > +		return -ENOMEM;
> > > > > +
> > > > > +	fb_req.width = mode->hdisplay;
> > > > > +	fb_req.height = mode->vdisplay;
> > > > > +	fb_req.pixel_format = buffer->format;
> > > > > +	fb_req.handles[0] = buffer->handle;
> > > > > +	fb_req.pitches[0] = buffer->pitch;
> > > > > +
> > > > > +	for (i = 0; i < num_fbs; i++) {
> > > > > +		fb_req.offsets[0] = i * mode->vdisplay * buffer->pitch;
> > > > > +		ret = drm_mode_addfb2(client->dev, &fb_req, client->file,
> > > > > +				      client->funcs->name);
> > > > > +		if (ret)
> > > > > +			goto err_remove;
> > > > > +		fb_ids[i] = fb_req.fb_id;
> > > > > +	}
> > > > > +
> > > > > +	buffer->fb_ids = fb_ids;
> > > > > +	buffer->num_fbs = num_fbs;
> > > > > +
> > > > > +	return 0;
> > > > > +
> > > > > +err_remove:
> > > > > +	for (i--; i >= 0; i--)
> > > > > +		drm_mode_rmfb(client->dev, fb_ids[i], client->file);
> > > > > +	kfree(fb_ids);
> > > > > +
> > > > > +	return ret;
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_buffer_addfb);
> > > > > +
> > > > > +int drm_client_buffer_rmfb(struct drm_client_buffer *buffer)
> > > > > +{
> > > > > +	unsigned int i;
> > > > > +	int ret;
> > > > > +
> > > > > +	if (!buffer || !buffer->num_fbs)
> > > > > +		return 0;
> > > > > +
> > > > > +	for (i = 0; i < buffer->num_fbs; i++) {
> > > > > +		ret = drm_mode_rmfb(buffer->client->dev, buffer->fb_ids[i],
> > > > > +				    buffer->client->file);
> > > > > +		if (ret)
> > > > > +			DRM_DEV_ERROR(buffer->client->dev->dev,
> > > > > +				      "Error removing FB:%u (%d)\n",
> > > > > +				      buffer->fb_ids[i], ret);
> > > > > +	}
> > > > > +
> > > > > +	kfree(buffer->fb_ids);
> > > > > +	buffer->fb_ids = NULL;
> > > > > +	buffer->num_fbs = 0;
> > > > > +
> > > > > +	return 0;
> > > > > +}
> > > > > +EXPORT_SYMBOL(drm_client_buffer_rmfb);
> > > > > diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> > > > > index f869de185986..db161337d87c 100644
> > > > > --- a/drivers/gpu/drm/drm_drv.c
> > > > > +++ b/drivers/gpu/drm/drm_drv.c
> > > > > @@ -33,6 +33,7 @@
> > > > >    #include <linux/mount.h>
> > > > >    #include <linux/slab.h>
> > > > > +#include <drm/drm_client.h>
> > > > >    #include <drm/drm_drv.h>
> > > > >    #include <drm/drmP.h>
> > > > > @@ -463,6 +464,7 @@ int drm_dev_init(struct drm_device *dev,
> > > > >    	dev->driver = driver;
> > > > >    	INIT_LIST_HEAD(&dev->filelist);
> > > > > +	INIT_LIST_HEAD(&dev->filelist_internal);
> > > > >    	INIT_LIST_HEAD(&dev->ctxlist);
> > > > >    	INIT_LIST_HEAD(&dev->vmalist);
> > > > >    	INIT_LIST_HEAD(&dev->maplist);
> > > > > @@ -787,6 +789,8 @@ int drm_dev_register(struct drm_device *dev, unsigned long flags)
> > > > >    		 dev->dev ? dev_name(dev->dev) : "virtual device",
> > > > >    		 dev->primary->index);
> > > > > +	drm_client_dev_register(dev);
> > > > > +
> > > > >    	goto out_unlock;
> > > > >    err_minors:
> > > > > @@ -839,6 +843,8 @@ void drm_dev_unregister(struct drm_device *dev)
> > > > >    	drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
> > > > >    	drm_minor_unregister(dev, DRM_MINOR_RENDER);
> > > > >    	drm_minor_unregister(dev, DRM_MINOR_CONTROL);
> > > > > +
> > > > > +	drm_client_dev_unregister(dev);
> > > > >    }
> > > > >    EXPORT_SYMBOL(drm_dev_unregister);
> > > > > diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
> > > > > index 55505378df47..bcc688e58776 100644
> > > > > --- a/drivers/gpu/drm/drm_file.c
> > > > > +++ b/drivers/gpu/drm/drm_file.c
> > > > > @@ -35,6 +35,7 @@
> > > > >    #include <linux/slab.h>
> > > > >    #include <linux/module.h>
> > > > > +#include <drm/drm_client.h>
> > > > >    #include <drm/drm_file.h>
> > > > >    #include <drm/drmP.h>
> > > > > @@ -443,6 +444,8 @@ void drm_lastclose(struct drm_device * dev)
> > > > >    	if (drm_core_check_feature(dev, DRIVER_LEGACY))
> > > > >    		drm_legacy_dev_reinit(dev);
> > > > > +
> > > > > +	drm_client_dev_lastclose(dev);
> > > > >    }
> > > > >    /**
> > > > > diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
> > > > > index 2d1643bdae78..5d2a6c6717f5 100644
> > > > > --- a/drivers/gpu/drm/drm_probe_helper.c
> > > > > +++ b/drivers/gpu/drm/drm_probe_helper.c
> > > > > @@ -33,6 +33,7 @@
> > > > >    #include <linux/moduleparam.h>
> > > > >    #include <drm/drmP.h>
> > > > > +#include <drm/drm_client.h>
> > > > >    #include <drm/drm_crtc.h>
> > > > >    #include <drm/drm_fourcc.h>
> > > > >    #include <drm/drm_crtc_helper.h>
> > > > > @@ -563,6 +564,8 @@ void drm_kms_helper_hotplug_event(struct drm_device *dev)
> > > > >    	drm_sysfs_hotplug_event(dev);
> > > > >    	if (dev->mode_config.funcs->output_poll_changed)
> > > > >    		dev->mode_config.funcs->output_poll_changed(dev);
> > > > > +
> > > > > +	drm_client_dev_hotplug(dev);
> > > > >    }
> > > > >    EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
> > > > > diff --git a/include/drm/drm_client.h b/include/drm/drm_client.h
> > > > > new file mode 100644
> > > > > index 000000000000..88f6f87919c5
> > > > > --- /dev/null
> > > > > +++ b/include/drm/drm_client.h
> > > > > @@ -0,0 +1,192 @@
> > > > > +/* SPDX-License-Identifier: GPL-2.0 */
> > > > > +
> > > > > +#include <linux/mutex.h>
> > > > > +
> > > > > +struct dma_buf;
> > > > > +struct drm_clip_rect;
> > > > > +struct drm_device;
> > > > > +struct drm_file;
> > > > > +struct drm_mode_modeinfo;
> > > > > +
> > > > > +struct drm_client_dev;
> > > > > +
> > > > > +/**
> > > > > + * struct drm_client_funcs - DRM client  callbacks
> > > > > + */
> > > > > +struct drm_client_funcs {
> > > > > +	/**
> > > > > +	 * @name:
> > > > > +	 *
> > > > > +	 * Name of the client.
> > > > > +	 */
> > > > > +	const char *name;
> > > > > +
> > > > > +	/**
> > > > > +	 * @new:
> > > > > +	 *
> > > > > +	 * Called when a client or a &drm_device is registered.
> > > > > +	 * If the callback returns anything but zero, then this client instance
> > > > > +	 * is dropped.
> > > > > +	 *
> > > > > +	 * This callback is mandatory.
> > > > > +	 */
> > > > > +	int (*new)(struct drm_client_dev *client);
> > > > > +
> > > > > +	/**
> > > > > +	 * @remove:
> > > > > +	 *
> > > > > +	 * Called when a &drm_device is unregistered or the client is
> > > > > +	 * unregistered. If zero is returned drm_client_free() is called
> > > > > +	 * automatically. If the client can't drop it's resources it should
> > > > > +	 * return non-zero and call drm_client_free() later.
> > > > > +	 *
> > > > > +	 * This callback is optional.
> > > > > +	 */
> > > > > +	int (*remove)(struct drm_client_dev *client);
> > > > > +
> > > > > +	/**
> > > > > +	 * @lastclose:
> > > > > +	 *
> > > > > +	 * Called on drm_lastclose(). The first client instance in the list
> > > > > +	 * that returns zero gets the privilege to restore and no more clients
> > > > > +	 * are called.
> > > > > +	 *
> > > > > +	 * This callback is optional.
> > > > > +	 */
> > > > > +	int (*lastclose)(struct drm_client_dev *client);
> > > > > +
> > > > > +	/**
> > > > > +	 * @hotplug:
> > > > > +	 *
> > > > > +	 * Called on drm_kms_helper_hotplug_event().
> > > > > +	 *
> > > > > +	 * This callback is optional.
> > > > > +	 */
> > > > > +	int (*hotplug)(struct drm_client_dev *client);
> > > > > +
> > > > > +// TODO
> > > > > +//	void (*suspend)(struct drm_client_dev *client);
> > > > > +//	void (*resume)(struct drm_client_dev *client);
> > > > > +};
> > > > > +
> > > > > +/**
> > > > > + * struct drm_client_dev - DRM client instance
> > > > > + */
> > > > > +struct drm_client_dev {
> > > > > +	struct list_head list;
> > > > > +	struct drm_device *dev;
> > > > > +	const struct drm_client_funcs *funcs;
> > > > > +	struct mutex lock;
> > > > > +	struct drm_file *file;
> > > > > +	unsigned int file_ref_count;
> > > > > +	u32 *crtcs;
> > > > > +	unsigned int num_crtcs;
> > > > > +	u32 min_width;
> > > > > +	u32 max_width;
> > > > > +	u32 min_height;
> > > > > +	u32 max_height;
> > > > > +	void *private;
> > > > > +};
> > > > > +
> > > > > +void drm_client_free(struct drm_client_dev *client);
> > > > > +int drm_client_register(const struct drm_client_funcs *funcs);
> > > > > +void drm_client_unregister(const struct drm_client_funcs *funcs);
> > > > > +
> > > > > +void drm_client_dev_register(struct drm_device *dev);
> > > > > +void drm_client_dev_unregister(struct drm_device *dev);
> > > > > +void drm_client_dev_hotplug(struct drm_device *dev);
> > > > > +void drm_client_dev_lastclose(struct drm_device *dev);
> > > > > +
> > > > > +int drm_client_get_file(struct drm_client_dev *client);
> > > > > +void drm_client_put_file(struct drm_client_dev *client);
> > > > > +struct drm_event *
> > > > > +drm_client_read_event(struct drm_client_dev *client, bool block);
> > > > > +
> > > > > +struct drm_client_connector {
> > > > > +	unsigned int conn_id;
> > > > > +	unsigned int status;
> > > > > +	unsigned int crtc_id;
> > > > > +	struct drm_mode_modeinfo *modes;
> > > > > +	unsigned int num_modes;
> > > > > +	bool has_tile;
> > > > > +	int tile_group;
> > > > > +	u8 tile_h_loc, tile_v_loc;
> > > > > +};
> > > > > +
> > > > > +struct drm_client_display {
> > > > > +	struct drm_client_dev *client;
> > > > > +
> > > > > +	struct drm_client_connector **connectors;
> > > > > +	unsigned int num_connectors;
> > > > > +
> > > > > +	struct mutex modes_lock;
> > > > > +	struct drm_mode_modeinfo *modes;
> > > > > +	unsigned int num_modes;
> > > > > +
> > > > > +	bool cloned;
> > > > > +	bool no_flushing;
> > > > > +};
> > > > > +
> > > > > +void drm_client_display_free(struct drm_client_display *display);
> > > > > +struct drm_client_display *
> > > > > +drm_client_display_get_first_enabled(struct drm_client_dev *client, bool strict);
> > > > > +
> > > > > +int drm_client_display_update_modes(struct drm_client_display *display,
> > > > > +				    bool *mode_changed);
> > > > > +
> > > > > +static inline bool
> > > > > +drm_client_display_is_tiled(struct drm_client_display *display)
> > > > > +{
> > > > > +	return !display->cloned && display->num_connectors > 1;
> > > > > +}
> > > > > +
> > > > > +int drm_client_display_dpms(struct drm_client_display *display, int mode);
> > > > > +int drm_client_display_wait_vblank(struct drm_client_display *display);
> > > > > +
> > > > > +struct drm_mode_modeinfo *
> > > > > +drm_client_display_first_mode(struct drm_client_display *display);
> > > > > +struct drm_mode_modeinfo *
> > > > > +drm_client_display_next_mode(struct drm_client_display *display,
> > > > > +			     struct drm_mode_modeinfo *mode);
> > > > > +
> > > > > +#define drm_client_display_for_each_mode(display, mode) \
> > > > > +	for (mode = drm_client_display_first_mode(display); mode; \
> > > > > +	     mode = drm_client_display_next_mode(display, mode))
> > > > > +
> > > > > +unsigned int
> > > > > +drm_client_display_preferred_depth(struct drm_client_display *display);
> > > > > +
> > > > > +int drm_client_display_commit_mode(struct drm_client_display *display,
> > > > > +				   u32 fb_id, struct drm_mode_modeinfo *mode);
> > > > > +unsigned int drm_client_display_current_fb(struct drm_client_display *display);
> > > > > +int drm_client_display_flush(struct drm_client_display *display, u32 fb_id,
> > > > > +			     struct drm_clip_rect *clips, unsigned int num_clips);
> > > > > +int drm_client_display_page_flip(struct drm_client_display *display, u32 fb_id,
> > > > > +				 bool event);
> > > > > +
> > > > > +struct drm_client_buffer {
> > > > > +	struct drm_client_dev *client;
> > > > > +	u32 width;
> > > > > +	u32 height;
> > > > > +	u32 format;
> > > > > +	u32 handle;
> > > > > +	u32 pitch;
> > > > > +	u64 size;
> > > > > +	struct dma_buf *dma_buf;
> > > > > +	void *vaddr;
> > > > > +
> > > > > +	unsigned int *fb_ids;
> > > > > +	unsigned int num_fbs;
> > > > > +};
> > > > > +
> > > > > +struct drm_client_buffer *
> > > > > +drm_client_framebuffer_create(struct drm_client_dev *client,
> > > > > +			      struct drm_mode_modeinfo *mode, u32 format);
> > > > > +void drm_client_framebuffer_delete(struct drm_client_buffer *buffer);
> > > > > +struct drm_client_buffer *
> > > > > +drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height,
> > > > > +			 u32 format);
> > > > > +void drm_client_buffer_delete(struct drm_client_buffer *buffer);
> > > > > +int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
> > > > > +			    struct drm_mode_modeinfo *mode);
> > > > > +int drm_client_buffer_rmfb(struct drm_client_buffer *buffer);
> > > > > diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h
> > > > > index 7c4fa32f3fc6..32dfed3d5a86 100644
> > > > > --- a/include/drm/drm_device.h
> > > > > +++ b/include/drm/drm_device.h
> > > > > @@ -67,6 +67,7 @@ struct drm_device {
> > > > >    	struct mutex filelist_mutex;
> > > > >    	struct list_head filelist;
> > > > > +	struct list_head filelist_internal;
> > > > >    	/** \name Memory management */
> > > > >    	/*@{ */
> > > > > diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
> > > > > index 5176c3797680..39af8a4be7b3 100644
> > > > > --- a/include/drm/drm_file.h
> > > > > +++ b/include/drm/drm_file.h
> > > > > @@ -248,6 +248,13 @@ struct drm_file {
> > > > >    	 */
> > > > >    	void *driver_priv;
> > > > > +	/**
> > > > > +	 * @user_priv:
> > > > > +	 *
> > > > > +	 * Optional pointer for user private data. Useful for in-kernel clients.
> > > > > +	 */
> > > > > +	void *user_priv;
> > > > > +
> > > > >    	/**
> > > > >    	 * @fbs:
> > > > >    	 *
> > > > > -- 
> > > > > 2.15.1
> > > > > 
>

Patch

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index deeefa7a1773..d4ae15f9ee9f 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -154,6 +154,8 @@  config DRM_SCHED
 	tristate
 	depends on DRM
 
+source "drivers/gpu/drm/client/Kconfig"
+
 source "drivers/gpu/drm/i2c/Kconfig"
 
 source "drivers/gpu/drm/arm/Kconfig"
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 50093ff4479b..8e06dc7eeca1 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -18,7 +18,7 @@  drm-y       :=	drm_auth.o drm_bufs.o drm_cache.o \
 		drm_encoder.o drm_mode_object.o drm_property.o \
 		drm_plane.o drm_color_mgmt.o drm_print.o \
 		drm_dumb_buffers.o drm_mode_config.o drm_vblank.o \
-		drm_syncobj.o drm_lease.o
+		drm_syncobj.o drm_lease.o client/drm_client.o
 
 drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o
 drm-$(CONFIG_DRM_VM) += drm_vm.o
@@ -103,3 +103,4 @@  obj-$(CONFIG_DRM_MXSFB)	+= mxsfb/
 obj-$(CONFIG_DRM_TINYDRM) += tinydrm/
 obj-$(CONFIG_DRM_PL111) += pl111/
 obj-$(CONFIG_DRM_TVE200) += tve200/
+obj-y			+= client/
diff --git a/drivers/gpu/drm/client/Kconfig b/drivers/gpu/drm/client/Kconfig
new file mode 100644
index 000000000000..4bb8e4655ff7
--- /dev/null
+++ b/drivers/gpu/drm/client/Kconfig
@@ -0,0 +1,4 @@ 
+menu "DRM Clients"
+	depends on DRM
+
+endmenu
diff --git a/drivers/gpu/drm/client/Makefile b/drivers/gpu/drm/client/Makefile
new file mode 100644
index 000000000000..f66554cd5c45
--- /dev/null
+++ b/drivers/gpu/drm/client/Makefile
@@ -0,0 +1 @@ 
+# SPDX-License-Identifier: GPL-2.0
diff --git a/drivers/gpu/drm/client/drm_client.c b/drivers/gpu/drm/client/drm_client.c
new file mode 100644
index 000000000000..a633bf747316
--- /dev/null
+++ b/drivers/gpu/drm/client/drm_client.c
@@ -0,0 +1,1612 @@ 
+// SPDX-License-Identifier: GPL-2.0
+// Copyright 2018 Noralf Trønnes
+
+#include <linux/dma-buf.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include <drm/drm_client.h>
+#include <drm/drm_connector.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_file.h>
+#include <drm/drm_ioctl.h>
+#include <drm/drmP.h>
+
+#include "drm_crtc_internal.h"
+#include "drm_internal.h"
+
+struct drm_client_funcs_entry {
+	struct list_head list;
+	const struct drm_client_funcs *funcs;
+};
+
+static LIST_HEAD(drm_client_list);
+static LIST_HEAD(drm_client_funcs_list);
+static DEFINE_MUTEX(drm_client_list_lock);
+
+static void drm_client_new(struct drm_device *dev,
+			   const struct drm_client_funcs *funcs)
+{
+	struct drm_client_dev *client;
+	int ret;
+
+	lockdep_assert_held(&drm_client_list_lock);
+
+	client = kzalloc(sizeof(*client), GFP_KERNEL);
+	if (!client)
+		return;
+
+	mutex_init(&client->lock);
+	client->dev = dev;
+	client->funcs = funcs;
+
+	ret = funcs->new(client);
+	DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n", funcs->name, ret);
+	if (ret) {
+		drm_client_free(client);
+		return;
+	}
+
+	list_add(&client->list, &drm_client_list);
+}
+
+/**
+ * drm_client_free - Free DRM client resources
+ * @client: DRM client
+ *
+ * This is called automatically on client removal unless the client returns
+ * non-zero in the &drm_client_funcs->remove callback. The fbdev client does
+ * this when it can't close &drm_file because userspace has an open fd.
+ */
+void drm_client_free(struct drm_client_dev *client)
+{
+	DRM_DEV_DEBUG_KMS(client->dev->dev, "%s\n", client->funcs->name);
+	if (WARN_ON(client->file)) {
+		client->file_ref_count = 1;
+		drm_client_put_file(client);
+	}
+	mutex_destroy(&client->lock);
+	kfree(client->crtcs);
+	kfree(client);
+}
+EXPORT_SYMBOL(drm_client_free);
+
+static void drm_client_remove(struct drm_client_dev *client)
+{
+	lockdep_assert_held(&drm_client_list_lock);
+
+	list_del(&client->list);
+
+	if (!client->funcs->remove || !client->funcs->remove(client))
+		drm_client_free(client);
+}
+
+/**
+ * drm_client_register - Register a DRM client
+ * @funcs: Client callbacks
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int drm_client_register(const struct drm_client_funcs *funcs)
+{
+	struct drm_client_funcs_entry *funcs_entry;
+	struct drm_device_list_iter iter;
+	struct drm_device *dev;
+
+	funcs_entry = kzalloc(sizeof(*funcs_entry), GFP_KERNEL);
+	if (!funcs_entry)
+		return -ENOMEM;
+
+	funcs_entry->funcs = funcs;
+
+	mutex_lock(&drm_global_mutex);
+	mutex_lock(&drm_client_list_lock);
+
+	drm_device_list_iter_begin(&iter);
+	drm_for_each_device_iter(dev, &iter)
+		if (drm_core_check_feature(dev, DRIVER_MODESET))
+			drm_client_new(dev, funcs);
+	drm_device_list_iter_end(&iter);
+
+	list_add(&funcs_entry->list, &drm_client_funcs_list);
+
+	mutex_unlock(&drm_client_list_lock);
+	mutex_unlock(&drm_global_mutex);
+
+	DRM_DEBUG_KMS("%s\n", funcs->name);
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_client_register);
+
+/**
+ * drm_client_unregister - Unregister a DRM client
+ * @funcs: Client callbacks
+ */
+void drm_client_unregister(const struct drm_client_funcs *funcs)
+{
+	struct drm_client_funcs_entry *funcs_entry;
+	struct drm_client_dev *client, *tmp;
+
+	mutex_lock(&drm_client_list_lock);
+
+	list_for_each_entry_safe(client, tmp, &drm_client_list, list) {
+		if (client->funcs == funcs)
+			drm_client_remove(client);
+	}
+
+	list_for_each_entry(funcs_entry, &drm_client_funcs_list, list) {
+		if (funcs_entry->funcs == funcs) {
+			list_del(&funcs_entry->list);
+			kfree(funcs_entry);
+			break;
+		}
+	}
+
+	mutex_unlock(&drm_client_list_lock);
+
+	DRM_DEBUG_KMS("%s\n", funcs->name);
+}
+EXPORT_SYMBOL(drm_client_unregister);
+
+void drm_client_dev_register(struct drm_device *dev)
+{
+	struct drm_client_funcs_entry *funcs_entry;
+
+	/*
+	 * Minors are created at the beginning of drm_dev_register(), but can
+	 * be removed again if the function fails. Since we iterate DRM devices
+	 * by walking DRM minors, we need to stay under this lock.
+	 */
+	lockdep_assert_held(&drm_global_mutex);
+
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return;
+
+	mutex_lock(&drm_client_list_lock);
+	list_for_each_entry(funcs_entry, &drm_client_funcs_list, list)
+		drm_client_new(dev, funcs_entry->funcs);
+	mutex_unlock(&drm_client_list_lock);
+}
+
+void drm_client_dev_unregister(struct drm_device *dev)
+{
+	struct drm_client_dev *client, *tmp;
+
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return;
+
+	mutex_lock(&drm_client_list_lock);
+	list_for_each_entry_safe(client, tmp, &drm_client_list, list)
+		if (client->dev == dev)
+			drm_client_remove(client);
+	mutex_unlock(&drm_client_list_lock);
+}
+
+void drm_client_dev_hotplug(struct drm_device *dev)
+{
+	struct drm_client_dev *client;
+	int ret;
+
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return;
+
+	mutex_lock(&drm_client_list_lock);
+	list_for_each_entry(client, &drm_client_list, list)
+		if (client->dev == dev && client->funcs->hotplug) {
+			ret = client->funcs->hotplug(client);
+			DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n",
+					  client->funcs->name, ret);
+		}
+	mutex_unlock(&drm_client_list_lock);
+}
+
+void drm_client_dev_lastclose(struct drm_device *dev)
+{
+	struct drm_client_dev *client;
+	int ret;
+
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return;
+
+	mutex_lock(&drm_client_list_lock);
+	list_for_each_entry(client, &drm_client_list, list)
+		if (client->dev == dev && client->funcs->lastclose) {
+			ret = client->funcs->lastclose(client);
+			DRM_DEV_DEBUG_KMS(dev->dev, "%s: ret=%d\n",
+					  client->funcs->name, ret);
+		}
+	mutex_unlock(&drm_client_list_lock);
+}
+
+/* Get static info */
+static int drm_client_init(struct drm_client_dev *client, struct drm_file *file)
+{
+	struct drm_mode_card_res card_res = {};
+	struct drm_device *dev = client->dev;
+	u32 *crtcs;
+	int ret;
+
+	ret = drm_mode_getresources(dev, &card_res, file, false);
+	if (ret)
+		return ret;
+	if (!card_res.count_crtcs)
+		return -ENOENT;
+
+	crtcs = kmalloc_array(card_res.count_crtcs, sizeof(*crtcs), GFP_KERNEL);
+	if (!crtcs)
+		return -ENOMEM;
+
+	card_res.count_fbs = 0;
+	card_res.count_connectors = 0;
+	card_res.count_encoders = 0;
+	card_res.crtc_id_ptr = (unsigned long)crtcs;
+
+	ret = drm_mode_getresources(dev, &card_res, file, false);
+	if (ret) {
+		kfree(crtcs);
+		return ret;
+	}
+
+	client->crtcs = crtcs;
+	client->num_crtcs = card_res.count_crtcs;
+	client->min_width = card_res.min_width;
+	client->max_width = card_res.max_width;
+	client->min_height = card_res.min_height;
+	client->max_height = card_res.max_height;
+
+	return 0;
+}
+
+/**
+ * drm_client_get_file - Get a DRM file
+ * @client: DRM client
+ *
+ * This function makes sure the client has a &drm_file available. The client
+ * doesn't normally need to call this, since all client functions that depends
+ * on a DRM file will call it. A matching call to drm_client_put_file() is
+ * necessary.
+ *
+ * The reason for not opening a DRM file when a @client is created is because
+ * we have to take a ref on the driver module due to &drm_driver->postclose
+ * being called in drm_file_free(). Having a DRM file open for the lifetime of
+ * the client instance would block driver module unload.
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int drm_client_get_file(struct drm_client_dev *client)
+{
+	struct drm_device *dev = client->dev;
+	struct drm_file *file;
+	int ret = 0;
+
+	mutex_lock(&client->lock);
+
+	if (client->file_ref_count++) {
+		mutex_unlock(&client->lock);
+		return 0;
+	}
+
+	if (!try_module_get(dev->driver->fops->owner)) {
+		ret = -ENODEV;
+		goto err_unlock;
+	}
+
+	drm_dev_get(dev);
+
+	file = drm_file_alloc(dev->primary);
+	if (IS_ERR(file)) {
+		ret = PTR_ERR(file);
+		goto err_put;
+	}
+
+	if (!client->crtcs) {
+		ret = drm_client_init(client, file);
+		if (ret)
+			goto err_free;
+	}
+
+	mutex_lock(&dev->filelist_mutex);
+	list_add(&file->lhead, &dev->filelist_internal);
+	mutex_unlock(&dev->filelist_mutex);
+
+	client->file = file;
+
+	mutex_unlock(&client->lock);
+
+	return 0;
+
+err_free:
+	drm_file_free(file);
+err_put:
+	drm_dev_put(dev);
+	module_put(dev->driver->fops->owner);
+err_unlock:
+	client->file_ref_count = 0;
+	mutex_unlock(&client->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL(drm_client_get_file);
+
+void drm_client_put_file(struct drm_client_dev *client)
+{
+	struct drm_device *dev = client->dev;
+
+	if (!client)
+		return;
+
+	mutex_lock(&client->lock);
+
+	if (WARN_ON(!client->file_ref_count))
+		goto out_unlock;
+
+	if (--client->file_ref_count)
+		goto out_unlock;
+
+	mutex_lock(&dev->filelist_mutex);
+	list_del(&client->file->lhead);
+	mutex_unlock(&dev->filelist_mutex);
+
+	drm_file_free(client->file);
+	client->file = NULL;
+	drm_dev_put(dev);
+	module_put(dev->driver->fops->owner);
+out_unlock:
+	mutex_unlock(&client->lock);
+}
+EXPORT_SYMBOL(drm_client_put_file);
+
+static struct drm_pending_event *
+drm_client_read_get_pending_event(struct drm_device *dev, struct drm_file *file)
+{
+	struct drm_pending_event *e = NULL;
+	int ret;
+
+	ret = mutex_lock_interruptible(&file->event_read_lock);
+	if (ret)
+		return ERR_PTR(ret);
+
+	spin_lock_irq(&dev->event_lock);
+	if (!list_empty(&file->event_list)) {
+		e = list_first_entry(&file->event_list,
+				     struct drm_pending_event, link);
+		file->event_space += e->event->length;
+		list_del(&e->link);
+	}
+	spin_unlock_irq(&dev->event_lock);
+
+	mutex_unlock(&file->event_read_lock);
+
+	return e;
+}
+
+struct drm_event *
+drm_client_read_event(struct drm_client_dev *client, bool block)
+{
+	struct drm_file *file = client->file;
+	struct drm_device *dev = client->dev;
+	struct drm_pending_event *e;
+	struct drm_event *event;
+	int ret;
+
+	/* Allocate so it fits all events, there's a sanity check later */
+	event = kzalloc(128, GFP_KERNEL);
+	if (!event)
+		return ERR_PTR(-ENOMEM);
+
+	e = drm_client_read_get_pending_event(dev, file);
+	if (IS_ERR(e)) {
+		ret = PTR_ERR(e);
+		goto err_free;
+	}
+
+	if (!e && !block) {
+		ret = 0;
+		goto err_free;
+	}
+
+	ret = wait_event_interruptible_timeout(file->event_wait,
+					       !list_empty(&file->event_list),
+					       5 * HZ);
+	if (!ret)
+		ret = -ETIMEDOUT;
+	if (ret < 0)
+		goto err_free;
+
+	e = drm_client_read_get_pending_event(dev, file);
+	if (IS_ERR_OR_NULL(e)) {
+		ret = PTR_ERR_OR_ZERO(e);
+		goto err_free;
+	}
+
+	if (WARN_ON(e->event->length > 128)) {
+		/* Increase buffer if this happens */
+		ret = -ENOMEM;
+		goto err_free;
+	}
+
+	memcpy(event, e->event, e->event->length);
+	kfree(e);
+
+	return event;
+
+err_free:
+	kfree(event);
+
+	return ret ? ERR_PTR(ret) : NULL;
+}
+EXPORT_SYMBOL(drm_client_read_event);
+
+static void drm_client_connector_free(struct drm_client_connector *connector)
+{
+	if (!connector)
+		return;
+	kfree(connector->modes);
+	kfree(connector);
+}
+
+static struct drm_client_connector *
+drm_client_get_connector(struct drm_client_dev *client, unsigned int id)
+{
+	struct drm_mode_get_connector req = {
+		.connector_id = id,
+	};
+	struct drm_client_connector *connector;
+	struct drm_mode_modeinfo *modes = NULL;
+	struct drm_device *dev = client->dev;
+	struct drm_connector *conn;
+	bool non_desktop;
+	int ret;
+
+	connector = kzalloc(sizeof(*connector), GFP_KERNEL);
+	if (!connector)
+		return ERR_PTR(-ENOMEM);
+
+	ret = drm_mode_getconnector(dev, &req, client->file, false);
+	if (ret)
+		goto err_free;
+
+	connector->conn_id = id;
+	connector->status = req.connection;
+
+	conn = drm_connector_lookup(dev, client->file, id);
+	if (!conn) {
+		ret = -ENOENT;
+		goto err_free;
+	}
+
+	non_desktop = conn->display_info.non_desktop;
+
+	connector->has_tile = conn->has_tile;
+	connector->tile_h_loc = conn->tile_h_loc;
+	connector->tile_v_loc = conn->tile_v_loc;
+	if (conn->tile_group)
+		connector->tile_group = conn->tile_group->id;
+
+	drm_connector_put(conn);
+
+	if (non_desktop) {
+		kfree(connector);
+		return NULL;
+	}
+
+	if (!req.count_modes)
+		return connector;
+
+	modes = kcalloc(req.count_modes, sizeof(*modes), GFP_KERNEL);
+	if (!modes) {
+		ret = -ENOMEM;
+		goto err_free;
+	}
+
+	connector->modes = modes;
+	connector->num_modes = req.count_modes;
+
+	req.count_props = 0;
+	req.count_encoders = 0;
+	req.modes_ptr = (unsigned long)modes;
+
+	ret = drm_mode_getconnector(dev, &req, client->file, false);
+	if (ret)
+		goto err_free;
+
+	return connector;
+
+err_free:
+	kfree(modes);
+	kfree(connector);
+
+	return ERR_PTR(ret);
+}
+
+static int drm_client_get_connectors(struct drm_client_dev *client,
+				     struct drm_client_connector ***connectors)
+{
+	struct drm_mode_card_res card_res = {};
+	struct drm_device *dev = client->dev;
+	int ret, num_connectors;
+	u32 *connector_ids;
+	unsigned int i;
+
+	ret = drm_mode_getresources(dev, &card_res, client->file, false);
+	if (ret)
+		return ret;
+	if (!card_res.count_connectors)
+		return 0;
+
+	num_connectors = card_res.count_connectors;
+	connector_ids = kcalloc(num_connectors,
+				sizeof(*connector_ids), GFP_KERNEL);
+	if (!connector_ids)
+		return -ENOMEM;
+
+	card_res.count_fbs = 0;
+	card_res.count_crtcs = 0;
+	card_res.count_encoders = 0;
+	card_res.connector_id_ptr = (unsigned long)connector_ids;
+
+	ret = drm_mode_getresources(dev, &card_res, client->file, false);
+	if (ret)
+		goto err_free;
+
+	*connectors = kcalloc(num_connectors, sizeof(**connectors), GFP_KERNEL);
+	if (!(*connectors)) {
+		ret = -ENOMEM;
+		goto err_free;
+	}
+
+	for (i = 0; i < num_connectors; i++) {
+		struct drm_client_connector *connector;
+
+		connector = drm_client_get_connector(client, connector_ids[i]);
+		if (IS_ERR(connector)) {
+			ret = PTR_ERR(connector);
+			goto err_free;
+		}
+		if (connector)
+			(*connectors)[i] = connector;
+		else
+			num_connectors--;
+	}
+
+	if (!num_connectors) {
+		ret = 0;
+		goto err_free;
+	}
+
+	return num_connectors;
+
+err_free:
+	if (connectors)
+		for (i = 0; i < num_connectors; i++)
+			drm_client_connector_free((*connectors)[i]);
+
+	kfree(connectors);
+	kfree(connector_ids);
+
+	return ret;
+}
+
+static bool
+drm_client_connector_is_enabled(struct drm_client_connector *connector,
+				bool strict)
+{
+	if (strict)
+		return connector->status == connector_status_connected;
+	else
+		return connector->status != connector_status_disconnected;
+}
+
+struct drm_mode_modeinfo *
+drm_client_display_first_mode(struct drm_client_display *display)
+{
+	if (!display->num_modes)
+		return NULL;
+	return display->modes;
+}
+EXPORT_SYMBOL(drm_client_display_first_mode);
+
+struct drm_mode_modeinfo *
+drm_client_display_next_mode(struct drm_client_display *display,
+			     struct drm_mode_modeinfo *mode)
+{
+	struct drm_mode_modeinfo *modes = display->modes;
+
+	if (++mode < &modes[display->num_modes])
+		return mode;
+
+	return NULL;
+}
+EXPORT_SYMBOL(drm_client_display_next_mode);
+
+static void
+drm_client_display_fill_tile_modes(struct drm_client_display *display,
+				   struct drm_mode_modeinfo *tile_modes)
+{
+	unsigned int i, j, num_modes = display->connectors[0]->num_modes;
+	struct drm_mode_modeinfo *tile_mode, *conn_mode;
+
+	if (!num_modes) {
+		kfree(tile_modes);
+		kfree(display->modes);
+		display->modes = NULL;
+		display->num_modes = 0;
+		return;
+	}
+
+	for (i = 0; i < num_modes; i++) {
+		tile_mode = &tile_modes[i];
+
+		conn_mode = &display->connectors[0]->modes[i];
+		tile_mode->clock = conn_mode->clock;
+		tile_mode->vscan = conn_mode->vscan;
+		tile_mode->vrefresh = conn_mode->vrefresh;
+		tile_mode->flags = conn_mode->flags;
+		tile_mode->type = conn_mode->type;
+
+		for (j = 0; j < display->num_connectors; j++) {
+			conn_mode = &display->connectors[j]->modes[i];
+
+			if (!display->connectors[j]->tile_h_loc) {
+				tile_mode->hdisplay += conn_mode->hdisplay;
+				tile_mode->hsync_start += conn_mode->hsync_start;
+				tile_mode->hsync_end += conn_mode->hsync_end;
+				tile_mode->htotal += conn_mode->htotal;
+			}
+
+			if (!display->connectors[j]->tile_v_loc) {
+				tile_mode->vdisplay += conn_mode->vdisplay;
+				tile_mode->vsync_start += conn_mode->vsync_start;
+				tile_mode->vsync_end += conn_mode->vsync_end;
+				tile_mode->vtotal += conn_mode->vtotal;
+			}
+		}
+	}
+
+	kfree(display->modes);
+	display->modes = tile_modes;
+	display->num_modes = num_modes;
+}
+
+/**
+ * drm_client_display_update_modes - Fetch display modes
+ * @display: Client display
+ * @mode_changed: Optional pointer to boolen which return whether the modes
+ *                have changed or not.
+ *
+ * This function can be used in the client hotplug callback to check if the
+ * video modes have changed and get them up-to-date.
+ *
+ * Returns:
+ * Number of modes on success, negative error code on failure.
+ */
+int drm_client_display_update_modes(struct drm_client_display *display,
+				    bool *mode_changed)
+{
+	unsigned int num_connectors = display->num_connectors;
+	struct drm_client_dev *client = display->client;
+	struct drm_mode_modeinfo *display_tile_modes;
+	struct drm_client_connector **connectors;
+	unsigned int i, num_modes = 0;
+	bool dummy_changed = false;
+	int ret;
+
+	if (mode_changed)
+		*mode_changed = false;
+	else
+		mode_changed = &dummy_changed;
+
+	if (display->cloned)
+		return 2;
+
+	ret = drm_client_get_file(client);
+	if (ret)
+		return ret;
+
+	connectors = kcalloc(num_connectors, sizeof(*connectors), GFP_KERNEL);
+	if (!connectors) {
+		ret = -ENOMEM;
+		goto out_put_file;
+	}
+
+	/* Get a new set for comparison */
+	for (i = 0; i < num_connectors; i++) {
+		connectors[i] = drm_client_get_connector(client, display->connectors[i]->conn_id);
+		if (IS_ERR_OR_NULL(connectors[i])) {
+			ret = PTR_ERR_OR_ZERO(connectors[i]);
+			if (!ret)
+				ret = -ENOENT;
+			goto out_cleanup;
+		}
+	}
+
+	/* All connectors should have the same number of modes */
+	num_modes = connectors[0]->num_modes;
+	for (i = 0; i < num_connectors; i++) {
+		if (num_modes != connectors[i]->num_modes) {
+			ret = -EINVAL;
+			goto out_cleanup;
+		}
+	}
+
+	if (num_connectors > 1) {
+		display_tile_modes = kcalloc(num_modes, sizeof(*display_tile_modes), GFP_KERNEL);
+		if (!display_tile_modes) {
+			ret = -ENOMEM;
+			goto out_cleanup;
+		}
+	}
+
+	mutex_lock(&display->modes_lock);
+
+	for (i = 0; i < num_connectors; i++) {
+		display->connectors[i]->status = connectors[i]->status;
+		if (display->connectors[i]->num_modes != connectors[i]->num_modes) {
+			display->connectors[i]->num_modes = connectors[i]->num_modes;
+			kfree(display->connectors[i]->modes);
+			display->connectors[i]->modes = connectors[i]->modes;
+			connectors[i]->modes = NULL;
+			*mode_changed = true;
+		}
+	}
+
+	if (num_connectors > 1)
+		drm_client_display_fill_tile_modes(display, display_tile_modes);
+	else
+		display->modes = display->connectors[0]->modes;
+
+	mutex_unlock(&display->modes_lock);
+
+out_cleanup:
+	for (i = 0; i < num_connectors; i++)
+		drm_client_connector_free(connectors[i]);
+	kfree(connectors);
+out_put_file:
+	drm_client_put_file(client);
+
+	return ret ? ret : num_modes;
+}
+EXPORT_SYMBOL(drm_client_display_update_modes);
+
+void drm_client_display_free(struct drm_client_display *display)
+{
+	unsigned int i;
+
+	if (!display)
+		return;
+
+	/* tile modes? */
+	if (display->modes != display->connectors[0]->modes)
+		kfree(display->modes);
+
+	for (i = 0; i < display->num_connectors; i++)
+		drm_client_connector_free(display->connectors[i]);
+
+	kfree(display->connectors);
+	mutex_destroy(&display->modes_lock);
+	kfree(display);
+}
+EXPORT_SYMBOL(drm_client_display_free);
+
+static struct drm_client_display *
+drm_client_display_alloc(struct drm_client_dev *client,
+			 unsigned int num_connectors)
+{
+	struct drm_client_display *display;
+	struct drm_client_connector **connectors;
+
+	display = kzalloc(sizeof(*display), GFP_KERNEL);
+	connectors = kcalloc(num_connectors, sizeof(*connectors), GFP_KERNEL);
+	if (!display || !connectors) {
+		kfree(display);
+		kfree(connectors);
+		return NULL;
+	}
+
+	mutex_init(&display->modes_lock);
+	display->client = client;
+	display->connectors = connectors;
+	display->num_connectors = num_connectors;
+
+	return display;
+}
+
+/* Logic is from drm_fb_helper */
+static struct drm_client_display *
+drm_client_connector_pick_cloned(struct drm_client_dev *client,
+				 struct drm_client_connector **connectors,
+				 unsigned int num_connectors)
+{
+	struct drm_mode_modeinfo modes[2], udmt_mode, *mode, *tmp;
+	struct drm_display_mode *dmt_display_mode = NULL;
+	unsigned int i, j, conns[2], num_conns = 0;
+	struct drm_client_connector *connector;
+	struct drm_device *dev = client->dev;
+	struct drm_client_display *display;
+
+	/* only contemplate cloning in the single crtc case */
+	if (dev->mode_config.num_crtc > 1)
+		return NULL;
+retry:
+	for (i = 0; i < num_connectors; i++) {
+		connector = connectors[i];
+		if (!connector || connector->has_tile || !connector->num_modes)
+			continue;
+
+		for (j = 0; j < connector->num_modes; j++) {
+			mode = &connector->modes[j];
+			if (dmt_display_mode) {
+				if (drm_umode_equal(&udmt_mode, mode)) {
+					conns[num_conns] = i;
+					modes[num_conns++] = *mode;
+					break;
+				}
+			} else {
+				if (mode->type & DRM_MODE_TYPE_USERDEF) {
+					conns[num_conns] = i;
+					modes[num_conns++] = *mode;
+					break;
+				}
+			}
+		}
+		if (num_conns == 2)
+			break;
+	}
+
+	if (num_conns == 2)
+		goto found;
+
+	if (dmt_display_mode)
+		return NULL;
+
+	dmt_display_mode = drm_mode_find_dmt(dev, 1024, 768, 60, false);
+	drm_mode_convert_to_umode(&udmt_mode, dmt_display_mode);
+	drm_mode_destroy(dev, dmt_display_mode);
+
+	goto retry;
+
+found:
+	tmp = kcalloc(2, sizeof(*tmp), GFP_KERNEL);
+	if (!tmp)
+		return ERR_PTR(-ENOMEM);
+
+	display = drm_client_display_alloc(client, 2);
+	if (!display) {
+		kfree(tmp);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	for (i = 0; i < 2; i++) {
+		connector = connectors[conns[i]];
+		display->connectors[i] = connector;
+		connectors[conns[i]] = NULL;
+		kfree(connector->modes);
+		tmp[i] = modes[i];
+		connector->modes = &tmp[i];
+		connector->num_modes = 1;
+	}
+
+	display->cloned = true;
+	display->modes = &tmp[0];
+	display->num_modes = 1;
+
+	return display;
+}
+
+static struct drm_client_display *
+drm_client_connector_pick_tile(struct drm_client_dev *client,
+			       struct drm_client_connector **connectors,
+			       unsigned int num_connectors)
+{
+	unsigned int i, num_conns, num_modes, tile_group = 0;
+	struct drm_mode_modeinfo *tile_modes = NULL;
+	struct drm_client_connector *connector;
+	struct drm_client_display *display;
+	u16 conns[32];
+
+	for (i = 0; i < num_connectors; i++) {
+		connector = connectors[i];
+		if (!connector || !connector->tile_group)
+			continue;
+
+		if (!tile_group) {
+			tile_group = connector->tile_group;
+			num_modes = connector->num_modes;
+		}
+
+		if (connector->tile_group != tile_group)
+			continue;
+
+		if (num_modes != connector->num_modes) {
+			DRM_ERROR("Tile connectors must have the same number of modes\n");
+			return ERR_PTR(-EINVAL);
+		}
+
+		conns[num_conns++] = i;
+		if (WARN_ON(num_conns == 33))
+			return ERR_PTR(-EINVAL);
+	}
+
+	if (!num_conns)
+		return NULL;
+
+	if (num_modes) {
+		tile_modes = kcalloc(num_modes, sizeof(*tile_modes), GFP_KERNEL);
+		if (!tile_modes)
+			return ERR_PTR(-ENOMEM);
+	}
+
+	display = drm_client_display_alloc(client, num_conns);
+	if (!display) {
+		kfree(tile_modes);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	if (num_modes)
+		drm_client_display_fill_tile_modes(display, tile_modes);
+
+	return display;
+}
+
+static struct drm_client_display *
+drm_client_connector_pick_not_tile(struct drm_client_dev *client,
+				   struct drm_client_connector **connectors,
+				   unsigned int num_connectors)
+{
+	struct drm_client_display *display;
+	unsigned int i;
+
+	for (i = 0; i < num_connectors; i++) {
+		if (!connectors[i] || connectors[i]->has_tile)
+			continue;
+		break;
+	}
+
+	if (i == num_connectors)
+		return NULL;
+
+	display = drm_client_display_alloc(client, 1);
+	if (!display)
+		return ERR_PTR(-ENOMEM);
+
+	display->connectors[0] = connectors[i];
+	connectors[i] = NULL;
+	display->modes = display->connectors[0]->modes;
+	display->num_modes = display->connectors[0]->num_modes;
+
+	return display;
+}
+
+/* Get connectors and bundle them up into displays */
+static int drm_client_get_displays(struct drm_client_dev *client,
+				   struct drm_client_display ***displays)
+{
+	int ret, num_connectors, num_displays = 0;
+	struct drm_client_connector **connectors;
+	struct drm_client_display *display;
+	unsigned int i;
+
+	ret = drm_client_get_file(client);
+	if (ret)
+		return ret;
+
+	num_connectors = drm_client_get_connectors(client, &connectors);
+	if (num_connectors <= 0) {
+		ret = num_connectors;
+		goto err_put_file;
+	}
+
+	*displays = kcalloc(num_connectors, sizeof(*displays), GFP_KERNEL);
+	if (!(*displays)) {
+		ret = -ENOMEM;
+		goto err_free;
+	}
+
+	display = drm_client_connector_pick_cloned(client, connectors,
+						   num_connectors);
+	if (IS_ERR(display)) {
+		ret = PTR_ERR(display);
+		goto err_free;
+	}
+	if (display)
+		(*displays)[num_displays++] = display;
+
+	for (i = 0; i < num_connectors; i++) {
+		display = drm_client_connector_pick_tile(client, connectors,
+							 num_connectors);
+		if (IS_ERR(display)) {
+			ret = PTR_ERR(display);
+			goto err_free;
+		}
+		if (!display)
+			break;
+		(*displays)[num_displays++] = display;
+	}
+
+	for (i = 0; i < num_connectors; i++) {
+		display = drm_client_connector_pick_not_tile(client, connectors,
+							     num_connectors);
+		if (IS_ERR(display)) {
+			ret = PTR_ERR(display);
+			goto err_free;
+		}
+		if (!display)
+			break;
+		(*displays)[num_displays++] = display;
+	}
+
+	for (i = 0; i < num_connectors; i++) {
+		if (connectors[i]) {
+			DRM_INFO("Connector %u fell through the cracks.\n",
+				 connectors[i]->conn_id);
+			drm_client_connector_free(connectors[i]);
+		}
+	}
+
+	drm_client_put_file(client);
+	kfree(connectors);
+
+	return num_displays;
+
+err_free:
+	for (i = 0; i < num_displays; i++)
+		drm_client_display_free((*displays)[i]);
+	kfree(*displays);
+	*displays = NULL;
+	for (i = 0; i < num_connectors; i++)
+		drm_client_connector_free(connectors[i]);
+	kfree(connectors);
+err_put_file:
+	drm_client_put_file(client);
+
+	return ret;
+}
+
+static bool
+drm_client_display_is_enabled(struct drm_client_display *display, bool strict)
+{
+	unsigned int i;
+
+	if (!display->num_modes)
+		return false;
+
+	for (i = 0; i < display->num_connectors; i++)
+		if (!drm_client_connector_is_enabled(display->connectors[i], strict))
+			return false;
+
+	return true;
+}
+
+/**
+ * drm_client_display_get_first_enabled - Get first enabled display
+ * @client: DRM client
+ * @strict: If true the connector(s) have to be connected, if false they can
+ *          also have unknown status.
+ *
+ * This function gets all connectors and bundles them into displays
+ * (tiled/cloned). It then picks the first one with connectors that is enabled
+ * according to @strict.
+ *
+ * Returns:
+ * Pointer to a client display if such a display was found, NULL if not found
+ * or an error pointer on failure.
+ */
+struct drm_client_display *
+drm_client_display_get_first_enabled(struct drm_client_dev *client, bool strict)
+{
+	struct drm_client_display **displays, *display = NULL;
+	int num_displays;
+	unsigned int i;
+
+	num_displays = drm_client_get_displays(client, &displays);
+	if (num_displays < 0)
+		return ERR_PTR(num_displays);
+	if (!num_displays)
+		return NULL;
+
+	for (i = 0; i < num_displays; i++) {
+		if (!display &&
+		    drm_client_display_is_enabled(displays[i], strict)) {
+			display = displays[i];
+			continue;
+		}
+		drm_client_display_free(displays[i]);
+	}
+
+	kfree(displays);
+
+	return display;
+}
+EXPORT_SYMBOL(drm_client_display_get_first_enabled);
+
+unsigned int
+drm_client_display_preferred_depth(struct drm_client_display *display)
+{
+	struct drm_connector *conn;
+	unsigned int ret;
+
+	conn = drm_connector_lookup(display->client->dev, NULL,
+				    display->connectors[0]->conn_id);
+	if (!conn)
+		return 0;
+
+	if (conn->cmdline_mode.bpp_specified)
+		ret = conn->cmdline_mode.bpp;
+	else
+		ret = display->client->dev->mode_config.preferred_depth;
+
+	drm_connector_put(conn);
+
+	return ret;
+}
+EXPORT_SYMBOL(drm_client_display_preferred_depth);
+
+int drm_client_display_dpms(struct drm_client_display *display, int mode)
+{
+	struct drm_mode_obj_set_property prop;
+
+	prop.value = mode;
+	prop.prop_id = display->client->dev->mode_config.dpms_property->base.id;
+	prop.obj_id = display->connectors[0]->conn_id;
+	prop.obj_type = DRM_MODE_OBJECT_CONNECTOR;
+
+	return drm_mode_obj_set_property(display->client->dev, &prop,
+					 display->client->file);
+}
+EXPORT_SYMBOL(drm_client_display_dpms);
+
+int drm_client_display_wait_vblank(struct drm_client_display *display)
+{
+	struct drm_crtc *crtc;
+	union drm_wait_vblank vblank_req = {
+		.request = {
+			.type = _DRM_VBLANK_RELATIVE,
+			.sequence = 1,
+		},
+	};
+
+	crtc = drm_crtc_find(display->client->dev, display->client->file,
+			     display->connectors[0]->crtc_id);
+	if (!crtc)
+		return -ENOENT;
+
+	vblank_req.request.type |= drm_crtc_index(crtc) << _DRM_VBLANK_HIGH_CRTC_SHIFT;
+
+	return drm_wait_vblank(display->client->dev, &vblank_req,
+			       display->client->file);
+}
+EXPORT_SYMBOL(drm_client_display_wait_vblank);
+
+static int drm_client_get_crtc_index(struct drm_client_dev *client, u32 id)
+{
+	int i;
+
+	for (i = 0; i < client->num_crtcs; i++)
+		if (client->crtcs[i] == id)
+			return i;
+
+	return -ENOENT;
+}
+
+static int drm_client_display_find_crtcs(struct drm_client_display *display)
+{
+	struct drm_client_dev *client = display->client;
+	struct drm_device *dev = client->dev;
+	struct drm_file *file = client->file;
+	u32 encoder_ids[DRM_CONNECTOR_MAX_ENCODER];
+	unsigned int i, j, available_crtcs = ~0;
+	struct drm_mode_get_connector conn_req;
+	struct drm_mode_get_encoder enc_req;
+	int ret;
+
+	/* Already done? */
+	if (display->connectors[0]->crtc_id)
+		return 0;
+
+	for (i = 0; i < display->num_connectors; i++) {
+		u32 active_crtcs = 0, crtcs_for_connector = 0;
+		int crtc_idx;
+
+		memset(&conn_req, 0, sizeof(conn_req));
+		conn_req.connector_id = display->connectors[i]->conn_id;
+		conn_req.encoders_ptr = (unsigned long)(encoder_ids);
+		conn_req.count_encoders = DRM_CONNECTOR_MAX_ENCODER;
+		ret = drm_mode_getconnector(dev, &conn_req, file, false);
+		if (ret)
+			return ret;
+
+		if (conn_req.encoder_id) {
+			memset(&enc_req, 0, sizeof(enc_req));
+			enc_req.encoder_id = conn_req.encoder_id;
+			ret = drm_mode_getencoder(dev, &enc_req, file);
+			if (ret)
+				return ret;
+			crtcs_for_connector |= enc_req.possible_crtcs;
+			if (crtcs_for_connector & available_crtcs)
+				goto found;
+		}
+
+		for (j = 0; j < conn_req.count_encoders; j++) {
+			memset(&enc_req, 0, sizeof(enc_req));
+			enc_req.encoder_id = encoder_ids[j];
+			ret = drm_mode_getencoder(dev, &enc_req, file);
+			if (ret)
+				return ret;
+
+			crtcs_for_connector |= enc_req.possible_crtcs;
+
+			if (enc_req.crtc_id) {
+				crtc_idx = drm_client_get_crtc_index(client, enc_req.crtc_id);
+				if (crtc_idx >= 0)
+					active_crtcs |= 1 << crtc_idx;
+			}
+		}
+
+found:
+		crtcs_for_connector &= available_crtcs;
+		active_crtcs &= available_crtcs;
+
+		if (!crtcs_for_connector)
+			return -ENOENT;
+
+		if (active_crtcs)
+			crtc_idx = ffs(active_crtcs) - 1;
+		else
+			crtc_idx = ffs(crtcs_for_connector) - 1;
+
+		if (crtc_idx >= client->num_crtcs)
+			return -EINVAL;
+
+		display->connectors[i]->crtc_id = client->crtcs[crtc_idx];
+		available_crtcs &= ~BIT(crtc_idx);
+	}
+
+	return 0;
+}
+
+/**
+ * drm_client_display_commit_mode - Commit a mode to the crtc(s)
+ * @display: Client display
+ * @fb_id: Framebuffer id
+ * @mode: Video mode
+ *
+ * Returns:
+ * Zero on success, negative error code on failure.
+ */
+int drm_client_display_commit_mode(struct drm_client_display *display,
+				   u32 fb_id, struct drm_mode_modeinfo *mode)
+{
+	struct drm_client_dev *client = display->client;
+	struct drm_device *dev = client->dev;
+	unsigned int num_crtcs = client->num_crtcs;
+	struct drm_file *file = client->file;
+	unsigned int *xoffsets = NULL, *yoffsets = NULL;
+	struct drm_mode_crtc *crtc_reqs, *req;
+	u32 cloned_conn_ids[2];
+	unsigned int i;
+	int idx, ret;
+
+	ret = drm_client_display_find_crtcs(display);
+	if (ret)
+		return ret;
+
+	crtc_reqs = kcalloc(num_crtcs, sizeof(*crtc_reqs), GFP_KERNEL);
+	if (!crtc_reqs)
+		return -ENOMEM;
+
+	for (i = 0; i < num_crtcs; i++)
+		crtc_reqs[i].crtc_id = client->crtcs[i];
+
+	if (drm_client_display_is_tiled(display)) {
+		/* TODO calculate tile crtc offsets */
+	}
+
+	for (i = 0; i < display->num_connectors; i++) {
+		idx = drm_client_get_crtc_index(client, display->connectors[i]->crtc_id);
+		if (idx < 0)
+			return -ENOENT;
+
+		req = &crtc_reqs[idx];
+
+		req->fb_id = fb_id;
+		if (xoffsets) {
+			req->x = xoffsets[i];
+			req->y = yoffsets[i];
+		}
+		req->mode_valid = 1;
+		req->mode = *mode;
+
+		if (display->cloned) {
+			cloned_conn_ids[0] = display->connectors[0]->conn_id;
+			cloned_conn_ids[1] = display->connectors[1]->conn_id;
+			req->set_connectors_ptr = (unsigned long)(cloned_conn_ids);
+			req->count_connectors = 2;
+			break;
+		}
+
+		req->set_connectors_ptr = (unsigned long)(&display->connectors[i]->conn_id);
+		req->count_connectors = 1;
+	}
+
+	for (i = 0; i < num_crtcs; i++) {
+		ret = drm_mode_setcrtc(dev, &crtc_reqs[i], file, false);
+		if (ret)
+			break;
+	}
+
+	kfree(xoffsets);
+	kfree(yoffsets);
+	kfree(crtc_reqs);
+
+	return ret;
+}
+EXPORT_SYMBOL(drm_client_display_commit_mode);
+
+unsigned int drm_client_display_current_fb(struct drm_client_display *display)
+{
+	struct drm_client_dev *client = display->client;
+	int ret;
+	struct drm_mode_crtc crtc_req = {
+		.crtc_id = display->connectors[0]->crtc_id,
+	};
+
+	ret = drm_mode_getcrtc(client->dev, &crtc_req, client->file);
+	if (ret)
+		return 0;
+
+	return crtc_req.fb_id;
+}
+EXPORT_SYMBOL(drm_client_display_current_fb);
+
+int drm_client_display_flush(struct drm_client_display *display, u32 fb_id,
+			     struct drm_clip_rect *clips, unsigned int num_clips)
+{
+	struct drm_client_dev *client = display->client;
+	struct drm_mode_fb_dirty_cmd dirty_req = {
+		.fb_id = fb_id,
+		.clips_ptr = (unsigned long)clips,
+		.num_clips = num_clips,
+	};
+	int ret;
+
+	if (display->no_flushing)
+		return 0;
+
+	ret = drm_mode_dirtyfb(client->dev, &dirty_req, client->file, false);
+	if (ret == -ENOSYS) {
+		ret = 0;
+		display->no_flushing = true;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(drm_client_display_flush);
+
+int drm_client_display_page_flip(struct drm_client_display *display, u32 fb_id,
+				 bool event)
+{
+	struct drm_client_dev *client = display->client;
+	struct drm_mode_crtc_page_flip_target page_flip_req = {
+		.crtc_id = display->connectors[0]->crtc_id,
+		.fb_id = fb_id,
+	};
+
+	if (event)
+		page_flip_req.flags = DRM_MODE_PAGE_FLIP_EVENT;
+
+	return drm_mode_page_flip(client->dev, &page_flip_req, client->file);
+	/*
+	 * TODO:
+	 * Where do we flush on page flip? Should the driver handle that?
+	 */
+}
+EXPORT_SYMBOL(drm_client_display_page_flip);
+
+/**
+ * drm_client_framebuffer_create - Create a client framebuffer
+ * @client: DRM client
+ * @mode: Display mode to create a buffer for
+ * @format: Buffer format
+ *
+ * This function creates a &drm_client_buffer which consists of a
+ * &drm_framebuffer backed by a dumb buffer. The dumb buffer is &dma_buf
+ * exported to aquire a virtual address which is stored in
+ * &drm_client_buffer->vaddr.
+ * Call drm_client_framebuffer_delete() to free the buffer.
+ *
+ * Returns:
+ * Pointer to a client buffer or an error pointer on failure.
+ */
+struct drm_client_buffer *
+drm_client_framebuffer_create(struct drm_client_dev *client,
+			      struct drm_mode_modeinfo *mode, u32 format)
+{
+	struct drm_client_buffer *buffer;
+	int ret;
+
+	buffer = drm_client_buffer_create(client, mode->hdisplay,
+					  mode->vdisplay, format);
+	if (IS_ERR(buffer))
+		return buffer;
+
+	ret = drm_client_buffer_addfb(buffer, mode);
+	if (ret) {
+		drm_client_buffer_delete(buffer);
+		return ERR_PTR(ret);
+	}
+
+	return buffer;
+}
+EXPORT_SYMBOL(drm_client_framebuffer_create);
+
+void drm_client_framebuffer_delete(struct drm_client_buffer *buffer)
+{
+	drm_client_buffer_rmfb(buffer);
+	drm_client_buffer_delete(buffer);
+}
+EXPORT_SYMBOL(drm_client_framebuffer_delete);
+
+struct drm_client_buffer *
+drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height,
+			 u32 format)
+{
+	struct drm_mode_create_dumb dumb_args = { 0 };
+	struct drm_prime_handle prime_args = { 0 };
+	struct drm_client_buffer *buffer;
+	struct dma_buf *dma_buf;
+	void *vaddr;
+	int ret;
+
+	buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
+	if (!buffer)
+		return ERR_PTR(-ENOMEM);
+
+	ret = drm_client_get_file(client);
+	if (ret)
+		goto err_free;
+
+	buffer->client = client;
+	buffer->width = width;
+	buffer->height = height;
+	buffer->format = format;
+
+	dumb_args.width = buffer->width;
+	dumb_args.height = buffer->height;
+	dumb_args.bpp = drm_format_plane_cpp(format, 0) * 8;
+	ret = drm_mode_create_dumb(client->dev, &dumb_args, client->file);
+	if (ret)
+		goto err_put_file;
+
+	buffer->handle = dumb_args.handle;
+	buffer->pitch = dumb_args.pitch;
+	buffer->size = dumb_args.size;
+
+	prime_args.handle = dumb_args.handle;
+	ret = drm_prime_handle_to_fd(client->dev, &prime_args, client->file);
+	if (ret)
+		goto err_delete;
+
+	dma_buf = dma_buf_get(prime_args.fd);
+	if (IS_ERR(dma_buf)) {
+		ret = PTR_ERR(dma_buf);
+		goto err_delete;
+	}
+
+	buffer->dma_buf = dma_buf;
+
+	vaddr = dma_buf_vmap(dma_buf);
+	if (!vaddr) {
+		ret = -ENOMEM;
+		goto err_delete;
+	}
+
+	buffer->vaddr = vaddr;
+
+	return buffer;
+
+err_delete:
+	drm_client_buffer_delete(buffer);
+err_put_file:
+	drm_client_put_file(client);
+err_free:
+	kfree(buffer);
+
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(drm_client_buffer_create);
+
+void drm_client_buffer_delete(struct drm_client_buffer *buffer)
+{
+	if (!buffer)
+		return;
+
+	if (buffer->vaddr)
+		dma_buf_vunmap(buffer->dma_buf, buffer->vaddr);
+
+	if (buffer->dma_buf)
+		dma_buf_put(buffer->dma_buf);
+
+	drm_mode_destroy_dumb(buffer->client->dev, buffer->handle,
+			      buffer->client->file);
+	drm_client_put_file(buffer->client);
+	kfree(buffer);
+}
+EXPORT_SYMBOL(drm_client_buffer_delete);
+
+int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
+			    struct drm_mode_modeinfo *mode)
+{
+	struct drm_client_dev *client = buffer->client;
+	struct drm_mode_fb_cmd2 fb_req = { };
+	unsigned int num_fbs, *fb_ids;
+	int i, ret;
+
+	if (buffer->num_fbs)
+		return -EINVAL;
+
+	if (mode->hdisplay > buffer->width || mode->vdisplay > buffer->height)
+		return -EINVAL;
+
+	num_fbs = buffer->height / mode->vdisplay;
+	fb_ids = kcalloc(num_fbs, sizeof(*fb_ids), GFP_KERNEL);
+	if (!fb_ids)
+		return -ENOMEM;
+
+	fb_req.width = mode->hdisplay;
+	fb_req.height = mode->vdisplay;
+	fb_req.pixel_format = buffer->format;
+	fb_req.handles[0] = buffer->handle;
+	fb_req.pitches[0] = buffer->pitch;
+
+	for (i = 0; i < num_fbs; i++) {
+		fb_req.offsets[0] = i * mode->vdisplay * buffer->pitch;
+		ret = drm_mode_addfb2(client->dev, &fb_req, client->file,
+				      client->funcs->name);
+		if (ret)
+			goto err_remove;
+		fb_ids[i] = fb_req.fb_id;
+	}
+
+	buffer->fb_ids = fb_ids;
+	buffer->num_fbs = num_fbs;
+
+	return 0;
+
+err_remove:
+	for (i--; i >= 0; i--)
+		drm_mode_rmfb(client->dev, fb_ids[i], client->file);
+	kfree(fb_ids);
+
+	return ret;
+}
+EXPORT_SYMBOL(drm_client_buffer_addfb);
+
+int drm_client_buffer_rmfb(struct drm_client_buffer *buffer)
+{
+	unsigned int i;
+	int ret;
+
+	if (!buffer || !buffer->num_fbs)
+		return 0;
+
+	for (i = 0; i < buffer->num_fbs; i++) {
+		ret = drm_mode_rmfb(buffer->client->dev, buffer->fb_ids[i],
+				    buffer->client->file);
+		if (ret)
+			DRM_DEV_ERROR(buffer->client->dev->dev,
+				      "Error removing FB:%u (%d)\n",
+				      buffer->fb_ids[i], ret);
+	}
+
+	kfree(buffer->fb_ids);
+	buffer->fb_ids = NULL;
+	buffer->num_fbs = 0;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_client_buffer_rmfb);
diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index f869de185986..db161337d87c 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -33,6 +33,7 @@ 
 #include <linux/mount.h>
 #include <linux/slab.h>
 
+#include <drm/drm_client.h>
 #include <drm/drm_drv.h>
 #include <drm/drmP.h>
 
@@ -463,6 +464,7 @@  int drm_dev_init(struct drm_device *dev,
 	dev->driver = driver;
 
 	INIT_LIST_HEAD(&dev->filelist);
+	INIT_LIST_HEAD(&dev->filelist_internal);
 	INIT_LIST_HEAD(&dev->ctxlist);
 	INIT_LIST_HEAD(&dev->vmalist);
 	INIT_LIST_HEAD(&dev->maplist);
@@ -787,6 +789,8 @@  int drm_dev_register(struct drm_device *dev, unsigned long flags)
 		 dev->dev ? dev_name(dev->dev) : "virtual device",
 		 dev->primary->index);
 
+	drm_client_dev_register(dev);
+
 	goto out_unlock;
 
 err_minors:
@@ -839,6 +843,8 @@  void drm_dev_unregister(struct drm_device *dev)
 	drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
 	drm_minor_unregister(dev, DRM_MINOR_RENDER);
 	drm_minor_unregister(dev, DRM_MINOR_CONTROL);
+
+	drm_client_dev_unregister(dev);
 }
 EXPORT_SYMBOL(drm_dev_unregister);
 
diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
index 55505378df47..bcc688e58776 100644
--- a/drivers/gpu/drm/drm_file.c
+++ b/drivers/gpu/drm/drm_file.c
@@ -35,6 +35,7 @@ 
 #include <linux/slab.h>
 #include <linux/module.h>
 
+#include <drm/drm_client.h>
 #include <drm/drm_file.h>
 #include <drm/drmP.h>
 
@@ -443,6 +444,8 @@  void drm_lastclose(struct drm_device * dev)
 
 	if (drm_core_check_feature(dev, DRIVER_LEGACY))
 		drm_legacy_dev_reinit(dev);
+
+	drm_client_dev_lastclose(dev);
 }
 
 /**
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index 2d1643bdae78..5d2a6c6717f5 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -33,6 +33,7 @@ 
 #include <linux/moduleparam.h>
 
 #include <drm/drmP.h>
+#include <drm/drm_client.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_fourcc.h>
 #include <drm/drm_crtc_helper.h>
@@ -563,6 +564,8 @@  void drm_kms_helper_hotplug_event(struct drm_device *dev)
 	drm_sysfs_hotplug_event(dev);
 	if (dev->mode_config.funcs->output_poll_changed)
 		dev->mode_config.funcs->output_poll_changed(dev);
+
+	drm_client_dev_hotplug(dev);
 }
 EXPORT_SYMBOL(drm_kms_helper_hotplug_event);
 
diff --git a/include/drm/drm_client.h b/include/drm/drm_client.h
new file mode 100644
index 000000000000..88f6f87919c5
--- /dev/null
+++ b/include/drm/drm_client.h
@@ -0,0 +1,192 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/mutex.h>
+
+struct dma_buf;
+struct drm_clip_rect;
+struct drm_device;
+struct drm_file;
+struct drm_mode_modeinfo;
+
+struct drm_client_dev;
+
+/**
+ * struct drm_client_funcs - DRM client  callbacks
+ */
+struct drm_client_funcs {
+	/**
+	 * @name:
+	 *
+	 * Name of the client.
+	 */
+	const char *name;
+
+	/**
+	 * @new:
+	 *
+	 * Called when a client or a &drm_device is registered.
+	 * If the callback returns anything but zero, then this client instance
+	 * is dropped.
+	 *
+	 * This callback is mandatory.
+	 */
+	int (*new)(struct drm_client_dev *client);
+
+	/**
+	 * @remove:
+	 *
+	 * Called when a &drm_device is unregistered or the client is
+	 * unregistered. If zero is returned drm_client_free() is called
+	 * automatically. If the client can't drop it's resources it should
+	 * return non-zero and call drm_client_free() later.
+	 *
+	 * This callback is optional.
+	 */
+	int (*remove)(struct drm_client_dev *client);
+
+	/**
+	 * @lastclose:
+	 *
+	 * Called on drm_lastclose(). The first client instance in the list
+	 * that returns zero gets the privilege to restore and no more clients
+	 * are called.
+	 *
+	 * This callback is optional.
+	 */
+	int (*lastclose)(struct drm_client_dev *client);
+
+	/**
+	 * @hotplug:
+	 *
+	 * Called on drm_kms_helper_hotplug_event().
+	 *
+	 * This callback is optional.
+	 */
+	int (*hotplug)(struct drm_client_dev *client);
+
+// TODO
+//	void (*suspend)(struct drm_client_dev *client);
+//	void (*resume)(struct drm_client_dev *client);
+};
+
+/**
+ * struct drm_client_dev - DRM client instance
+ */
+struct drm_client_dev {
+	struct list_head list;
+	struct drm_device *dev;
+	const struct drm_client_funcs *funcs;
+	struct mutex lock;
+	struct drm_file *file;
+	unsigned int file_ref_count;
+	u32 *crtcs;
+	unsigned int num_crtcs;
+	u32 min_width;
+	u32 max_width;
+	u32 min_height;
+	u32 max_height;
+	void *private;
+};
+
+void drm_client_free(struct drm_client_dev *client);
+int drm_client_register(const struct drm_client_funcs *funcs);
+void drm_client_unregister(const struct drm_client_funcs *funcs);
+
+void drm_client_dev_register(struct drm_device *dev);
+void drm_client_dev_unregister(struct drm_device *dev);
+void drm_client_dev_hotplug(struct drm_device *dev);
+void drm_client_dev_lastclose(struct drm_device *dev);
+
+int drm_client_get_file(struct drm_client_dev *client);
+void drm_client_put_file(struct drm_client_dev *client);
+struct drm_event *
+drm_client_read_event(struct drm_client_dev *client, bool block);
+
+struct drm_client_connector {
+	unsigned int conn_id;
+	unsigned int status;
+	unsigned int crtc_id;
+	struct drm_mode_modeinfo *modes;
+	unsigned int num_modes;
+	bool has_tile;
+	int tile_group;
+	u8 tile_h_loc, tile_v_loc;
+};
+
+struct drm_client_display {
+	struct drm_client_dev *client;
+
+	struct drm_client_connector **connectors;
+	unsigned int num_connectors;
+
+	struct mutex modes_lock;
+	struct drm_mode_modeinfo *modes;
+	unsigned int num_modes;
+
+	bool cloned;
+	bool no_flushing;
+};
+
+void drm_client_display_free(struct drm_client_display *display);
+struct drm_client_display *
+drm_client_display_get_first_enabled(struct drm_client_dev *client, bool strict);
+
+int drm_client_display_update_modes(struct drm_client_display *display,
+				    bool *mode_changed);
+
+static inline bool
+drm_client_display_is_tiled(struct drm_client_display *display)
+{
+	return !display->cloned && display->num_connectors > 1;
+}
+
+int drm_client_display_dpms(struct drm_client_display *display, int mode);
+int drm_client_display_wait_vblank(struct drm_client_display *display);
+
+struct drm_mode_modeinfo *
+drm_client_display_first_mode(struct drm_client_display *display);
+struct drm_mode_modeinfo *
+drm_client_display_next_mode(struct drm_client_display *display,
+			     struct drm_mode_modeinfo *mode);
+
+#define drm_client_display_for_each_mode(display, mode) \
+	for (mode = drm_client_display_first_mode(display); mode; \
+	     mode = drm_client_display_next_mode(display, mode))
+
+unsigned int
+drm_client_display_preferred_depth(struct drm_client_display *display);
+
+int drm_client_display_commit_mode(struct drm_client_display *display,
+				   u32 fb_id, struct drm_mode_modeinfo *mode);
+unsigned int drm_client_display_current_fb(struct drm_client_display *display);
+int drm_client_display_flush(struct drm_client_display *display, u32 fb_id,
+			     struct drm_clip_rect *clips, unsigned int num_clips);
+int drm_client_display_page_flip(struct drm_client_display *display, u32 fb_id,
+				 bool event);
+
+struct drm_client_buffer {
+	struct drm_client_dev *client;
+	u32 width;
+	u32 height;
+	u32 format;
+	u32 handle;
+	u32 pitch;
+	u64 size;
+	struct dma_buf *dma_buf;
+	void *vaddr;
+
+	unsigned int *fb_ids;
+	unsigned int num_fbs;
+};
+
+struct drm_client_buffer *
+drm_client_framebuffer_create(struct drm_client_dev *client,
+			      struct drm_mode_modeinfo *mode, u32 format);
+void drm_client_framebuffer_delete(struct drm_client_buffer *buffer);
+struct drm_client_buffer *
+drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height,
+			 u32 format);
+void drm_client_buffer_delete(struct drm_client_buffer *buffer);
+int drm_client_buffer_addfb(struct drm_client_buffer *buffer,
+			    struct drm_mode_modeinfo *mode);
+int drm_client_buffer_rmfb(struct drm_client_buffer *buffer);
diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h
index 7c4fa32f3fc6..32dfed3d5a86 100644
--- a/include/drm/drm_device.h
+++ b/include/drm/drm_device.h
@@ -67,6 +67,7 @@  struct drm_device {
 
 	struct mutex filelist_mutex;
 	struct list_head filelist;
+	struct list_head filelist_internal;
 
 	/** \name Memory management */
 	/*@{ */
diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h
index 5176c3797680..39af8a4be7b3 100644
--- a/include/drm/drm_file.h
+++ b/include/drm/drm_file.h
@@ -248,6 +248,13 @@  struct drm_file {
 	 */
 	void *driver_priv;
 
+	/**
+	 * @user_priv:
+	 *
+	 * Optional pointer for user private data. Useful for in-kernel clients.
+	 */
+	void *user_priv;
+
 	/**
 	 * @fbs:
 	 *