From patchwork Wed Dec 11 23:03:18 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Imre Deak X-Patchwork-Id: 13904332 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 199ECE77180 for ; Wed, 11 Dec 2024 23:02:56 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 061B410EC48; Wed, 11 Dec 2024 23:02:54 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="a/2u2hc3"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.17]) by gabe.freedesktop.org (Postfix) with ESMTPS id 88BF110EC48; Wed, 11 Dec 2024 23:02:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1733958173; x=1765494173; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=5AMCYrr3tmfkJeGILEYoPC9m08zwnWcuet8VqnZ36SQ=; b=a/2u2hc3aD/l1mn9XbBr5qeVR32JVvy7xrssnGiV05Q0JEA3W4awgqHU a0FY0iJfoZ84vbri9uW6ozYhWrmxJy94L7+uGos55dHGG/0udcqazTbd8 12mZSKbGRhWc+3SEdl38lT/zMpX+xHeug1bbhSIchCPws7Q1F55qrCI6h Lr5sfr674CYhS/wyAXtgWTDtt+0CIGNQ+R+hrQLM2FcieI52W1o3FY+cH J2ByvzjjBoThccEBpL4hDFRTy9MPZG/BBjm5AEPtfSZ+iYQenw+md+xVB IiyrRzOBcHBo0/742oWkbtZTdopl/f9RuLSGBFKIKZ8bETGlrkguwZP/B g==; X-CSE-ConnectionGUID: Tn3GAuv7TI6dVuMAEA4pPQ== X-CSE-MsgGUID: JOW2xDV5TrW4cffBGoKvyA== X-IronPort-AV: E=McAfee;i="6700,10204,11283"; a="34401466" X-IronPort-AV: E=Sophos;i="6.12,226,1728975600"; d="scan'208";a="34401466" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by orvoesa109.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Dec 2024 15:02:53 -0800 X-CSE-ConnectionGUID: 8SPDvEITS3G0x5huELUbbA== X-CSE-MsgGUID: gHHJxNa2SlyxAdhKGfdRVg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,224,1728975600"; d="scan'208";a="126962338" Received: from ideak-desk.fi.intel.com ([10.237.72.78]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Dec 2024 15:02:50 -0800 From: Imre Deak To: intel-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org, Jani Nikula , Simona Vetter , Maxime Ripard , Rodrigo Vivi Subject: [PATCH v3 01/11] drm/connector: Add a way to init/add a connector in separate steps Date: Thu, 12 Dec 2024 01:03:18 +0200 Message-ID: <20241211230328.4012496-2-imre.deak@intel.com> X-Mailer: git-send-email 2.44.2 In-Reply-To: <20241211230328.4012496-1-imre.deak@intel.com> References: <20241211230328.4012496-1-imre.deak@intel.com> MIME-Version: 1.0 X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Atm when the connector is added to the drm_mode_config::connector_list, the connector may not be fully initialized yet. This is not a problem for static connectors initialized/added during driver loading, for which the driver ensures that look-ups via the above list are not possible until all the connector and other required state is fully initialized already. It's also not a problem for user space looking up either a static or dynamic (see what this is below) connector, since this will be only possible once the connector is registered. A dynamic - atm only a DP MST - connector can be initialized and added after the load time initialization is done. Such a connector may be looked up by in-kernel users once it's added to the connector list. In particular a hotplug handler could perform a detection on all the connectors on the list and hence find a connector there which isn't yet initialized. For instance the connector's helper hooks may be unset, leading to a NULL dereference while the detect helper calls the connector's drm_connector_helper_funcs::detect() or detect_ctx() handler. To resolve the above issue, add a way for dynamic connectors to separately initialize the DRM core specific parts of the connector without adding it to the connector list - by calling the new drm_connector_dynamic_init() - and to add the connector to the list later once all the initialization is complete and the connector is registered - by calling the new drm_connector_dynamic_register(). Adding the above 2 functions was also motivated to make the distinction of the interface between static and dynamic connectors clearer: Drivers should manually initialize and register only dynamic connectors (with the above 2 functions). A driver should only initialize a static connector (with one of the drm_connector_init*, drmm_connector_init* functions) while the registration of the connector will be done automatically by DRM core. v2: (Jani) - Let initing DDC as well via drm_connector_init_core(). - Rename __drm_connector_init to drm_connector_init_core_and_add(). v3: - Rename drm_connector_init_core() to drm_connector_dynamic_init(). (Sima) - Instead of exporting drm_connector_add(), move adding the connector to the registration step via a new drm_connector_dynamic_register(). (Sima) - Update drm_connector_dynamic_init()'s function documentation and the commit log according to the above changes. - Update the commit log describing the problematic scenario during connector detection. (Maxime) Cc: Jani Nikula Cc: Simona Vetter Cc: Maxime Ripard Reviewed-by: Rodrigo Vivi (v1) Signed-off-by: Imre Deak Reviewed-by: Lyude Paul --- drivers/gpu/drm/drm_connector.c | 150 +++++++++++++++++++++++++++----- include/drm/drm_connector.h | 6 ++ 2 files changed, 136 insertions(+), 20 deletions(-) diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index fc35f47e2849e..a53e5629ba6c1 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -218,11 +218,11 @@ void drm_connector_free_work_fn(struct work_struct *work) } } -static int __drm_connector_init(struct drm_device *dev, - struct drm_connector *connector, - const struct drm_connector_funcs *funcs, - int connector_type, - struct i2c_adapter *ddc) +static int drm_connector_init_only(struct drm_device *dev, + struct drm_connector *connector, + const struct drm_connector_funcs *funcs, + int connector_type, + struct i2c_adapter *ddc) { struct drm_mode_config *config = &dev->mode_config; int ret; @@ -273,6 +273,7 @@ static int __drm_connector_init(struct drm_device *dev, /* provide ddc symlink in sysfs */ connector->ddc = ddc; + INIT_LIST_HEAD(&connector->head); INIT_LIST_HEAD(&connector->global_connector_list_entry); INIT_LIST_HEAD(&connector->probed_modes); INIT_LIST_HEAD(&connector->modes); @@ -288,14 +289,6 @@ static int __drm_connector_init(struct drm_device *dev, drm_connector_get_cmdline_mode(connector); - /* We should add connectors at the end to avoid upsetting the connector - * index too much. - */ - spin_lock_irq(&config->connector_list_lock); - list_add_tail(&connector->head, &config->connector_list); - config->num_connector++; - spin_unlock_irq(&config->connector_list_lock); - if (connector_type != DRM_MODE_CONNECTOR_VIRTUAL && connector_type != DRM_MODE_CONNECTOR_WRITEBACK) drm_connector_attach_edid_property(connector); @@ -332,6 +325,58 @@ static int __drm_connector_init(struct drm_device *dev, return ret; } +static void drm_connector_add(struct drm_connector *connector) +{ + struct drm_device *dev = connector->dev; + struct drm_mode_config *config = &dev->mode_config; + + /* + * TODO: Change this to a WARN, once all drivers are converted to + * call drm_connector_dynamic_init() for MST connectors. + */ + if (!list_empty(&connector->head)) + return; + + spin_lock_irq(&config->connector_list_lock); + list_add_tail(&connector->head, &config->connector_list); + config->num_connector++; + spin_unlock_irq(&config->connector_list_lock); +} + +static void drm_connector_remove(struct drm_connector *connector) +{ + struct drm_device *dev = connector->dev; + + /* + * For dynamic connectors drm_connector_cleanup() can call this function + * before the connector is registered and added to the list. + */ + if (list_empty(&connector->head)) + return; + + spin_lock_irq(&dev->mode_config.connector_list_lock); + list_del_init(&connector->head); + dev->mode_config.num_connector--; + spin_unlock_irq(&dev->mode_config.connector_list_lock); +} + +static int drm_connector_init_and_add(struct drm_device *dev, + struct drm_connector *connector, + const struct drm_connector_funcs *funcs, + int connector_type, + struct i2c_adapter *ddc) +{ + int ret; + + ret = drm_connector_init_only(dev, connector, funcs, connector_type, ddc); + if (ret) + return ret; + + drm_connector_add(connector); + + return 0; +} + /** * drm_connector_init - Init a preallocated connector * @dev: DRM device @@ -361,10 +406,51 @@ int drm_connector_init(struct drm_device *dev, if (drm_WARN_ON(dev, !(funcs && funcs->destroy))) return -EINVAL; - return __drm_connector_init(dev, connector, funcs, connector_type, NULL); + return drm_connector_init_and_add(dev, connector, funcs, connector_type, NULL); } EXPORT_SYMBOL(drm_connector_init); +/** + * drm_connector_dynamic_init - Init a preallocated dynamic connector + * @dev: DRM device + * @connector: the connector to init + * @funcs: callbacks for this connector + * @connector_type: user visible type of the connector + * @ddc: pointer to the associated ddc adapter + * + * Initialises a preallocated dynamic connector. Connectors should be + * subclassed as part of driver connector objects. The connector + * structure should not be allocated with devm_kzalloc(). + * + * Drivers should call this for dynamic connectors which can be hotplugged + * after drm_dev_register() has been called already, e.g. DP MST connectors. + * For all other - static - connectors, drivers should call one of the + * drm_connector_init*()/drmm_connector_init*() functions. + * + * After calling this function the drivers must call + * drm_connector_dynamic_register(). + * + * To remove the connector the driver must call drm_connector_unregister() + * followed by drm_connector_put(). Putting the last reference will call the + * driver's &drm_connector_funcs.destroy hook, which in turn must call + * drm_connector_cleanup() and free the connector structure. + * + * Returns: + * Zero on success, error code on failure. + */ +int drm_connector_dynamic_init(struct drm_device *dev, + struct drm_connector *connector, + const struct drm_connector_funcs *funcs, + int connector_type, + struct i2c_adapter *ddc) +{ + if (drm_WARN_ON(dev, !(funcs && funcs->destroy))) + return -EINVAL; + + return drm_connector_init_only(dev, connector, funcs, connector_type, ddc); +} +EXPORT_SYMBOL(drm_connector_dynamic_init); + /** * drm_connector_init_with_ddc - Init a preallocated connector * @dev: DRM device @@ -398,7 +484,7 @@ int drm_connector_init_with_ddc(struct drm_device *dev, if (drm_WARN_ON(dev, !(funcs && funcs->destroy))) return -EINVAL; - return __drm_connector_init(dev, connector, funcs, connector_type, ddc); + return drm_connector_init_and_add(dev, connector, funcs, connector_type, ddc); } EXPORT_SYMBOL(drm_connector_init_with_ddc); @@ -442,7 +528,7 @@ int drmm_connector_init(struct drm_device *dev, if (drm_WARN_ON(dev, funcs && funcs->destroy)) return -EINVAL; - ret = __drm_connector_init(dev, connector, funcs, connector_type, ddc); + ret = drm_connector_init_and_add(dev, connector, funcs, connector_type, ddc); if (ret) return ret; @@ -659,10 +745,8 @@ void drm_connector_cleanup(struct drm_connector *connector) connector->name = NULL; fwnode_handle_put(connector->fwnode); connector->fwnode = NULL; - spin_lock_irq(&dev->mode_config.connector_list_lock); - list_del(&connector->head); - dev->mode_config.num_connector--; - spin_unlock_irq(&dev->mode_config.connector_list_lock); + + drm_connector_remove(connector); WARN_ON(connector->state && !connector->funcs->atomic_destroy_state); if (connector->state && connector->funcs->atomic_destroy_state) @@ -749,6 +833,32 @@ int drm_connector_register(struct drm_connector *connector) } EXPORT_SYMBOL(drm_connector_register); +/** + * drm_connector_dynamic_register - register a dynamic connector + * @connector: the connector to register + * + * Register userspace interfaces for a connector. Only call this for connectors + * initialized by calling drm_connector_dynamic_init(). All other connectors + * will be registered automatically when calling drm_dev_register(). + * + * When the connector is no longer available the driver must call + * drm_connector_unregister(). + * + * Returns: + * Zero on success, error code on failure. + */ +int drm_connector_dynamic_register(struct drm_connector *connector) +{ + /* Was the connector inited already? */ + if (WARN_ON(!(connector->funcs && connector->funcs->destroy))) + return -EINVAL; + + drm_connector_add(connector); + + return drm_connector_register(connector); +} +EXPORT_SYMBOL(drm_connector_dynamic_register); + /** * drm_connector_unregister - unregister a connector * @connector: the connector to unregister diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h index e3fa43291f449..f766d194221d1 100644 --- a/include/drm/drm_connector.h +++ b/include/drm/drm_connector.h @@ -2126,6 +2126,11 @@ int drm_connector_init(struct drm_device *dev, struct drm_connector *connector, const struct drm_connector_funcs *funcs, int connector_type); +int drm_connector_dynamic_init(struct drm_device *dev, + struct drm_connector *connector, + const struct drm_connector_funcs *funcs, + int connector_type, + struct i2c_adapter *ddc); int drm_connector_init_with_ddc(struct drm_device *dev, struct drm_connector *connector, const struct drm_connector_funcs *funcs, @@ -2147,6 +2152,7 @@ int drmm_connector_hdmi_init(struct drm_device *dev, unsigned int max_bpc); void drm_connector_attach_edid_property(struct drm_connector *connector); int drm_connector_register(struct drm_connector *connector); +int drm_connector_dynamic_register(struct drm_connector *connector); void drm_connector_unregister(struct drm_connector *connector); int drm_connector_attach_encoder(struct drm_connector *connector, struct drm_encoder *encoder);