From patchwork Wed Jan 29 12:05:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Zimmermann X-Patchwork-Id: 11356019 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 91861138C for ; Wed, 29 Jan 2020 12:07:07 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6D6CE2071E for ; Wed, 29 Jan 2020 12:07:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6D6CE2071E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iwm6N-0005as-UB; Wed, 29 Jan 2020 12:05:47 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1iwm6N-0005ac-4Q for xen-devel@lists.xenproject.org; Wed, 29 Jan 2020 12:05:47 +0000 X-Inumbo-ID: a8404d85-428f-11ea-889e-12813bfff9fa Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id a8404d85-428f-11ea-889e-12813bfff9fa; Wed, 29 Jan 2020 12:05:36 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id B1235AE46; Wed, 29 Jan 2020 12:05:34 +0000 (UTC) From: Thomas Zimmermann To: airlied@linux.ie, daniel@ffwll.ch, kraxel@redhat.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, hdegoede@redhat.com, david@lechnology.com, noralf@tronnes.org, sean@poorly.run, oleksandr_andrushchenko@epam.com, sam@ravnborg.org, laurent.pinchart@ideasonboard.com, emil.velikov@collabora.com Date: Wed, 29 Jan 2020 13:05:17 +0100 Message-Id: <20200129120531.6891-2-tzimmermann@suse.de> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200129120531.6891-1-tzimmermann@suse.de> References: <20200129120531.6891-1-tzimmermann@suse.de> MIME-Version: 1.0 Subject: [Xen-devel] [PATCH v5 01/15] drm: Initialize struct drm_crtc_state.no_vblank from device settings X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Daniel Vetter , xen-devel@lists.xenproject.org, Thomas Zimmermann , dri-devel@lists.freedesktop.org, virtualization@lists.linux-foundation.org Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" At the end of a commit, atomic helpers can generate a fake VBLANK event automatically. Originally implemented for writeback connectors, the functionality can be used by any driver and/or hardware without proper VBLANK interrupt. The patch updates the documentation to make this behaviour official: settings struct drm_crtc_state.no_vblank to true enables automatic generation of fake VBLANK events. The new interface drm_dev_has_vblank() returns true if vblanking has been initialized for a device, or false otherwise. Atomic helpers use this function when initializing no_vblank in the CRTC state in drm_atomic_helper_check_modeset(). If vblanking has been initialized for a device, no_blank is disabled. Otherwise it's enabled. Hence, atomic helpers will automatically send out fake VBLANK events with any driver that did not initialize vblanking. v5: * more precise documentation and commit message v4: * replace drm_crtc_has_vblank() with drm_dev_has_vblank() * add drm_dev_has_vblank() in this patch * move driver changes into separate patches v3: * squash all related changes patches into this patch Signed-off-by: Thomas Zimmermann Acked-by: Gerd Hoffmann Reviewed-by: Daniel Vetter --- drivers/gpu/drm/drm_atomic_helper.c | 10 ++++++++- drivers/gpu/drm/drm_vblank.c | 28 ++++++++++++++++++++++++ include/drm/drm_crtc.h | 34 +++++++++++++++++++++++------ include/drm/drm_simple_kms_helper.h | 7 ++++-- include/drm/drm_vblank.h | 1 + 5 files changed, 70 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 4511c2e07bb9..d7b73cd89b79 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -583,6 +583,7 @@ mode_valid(struct drm_atomic_state *state) * &drm_crtc_state.connectors_changed is set when a connector is added or * removed from the CRTC. &drm_crtc_state.active_changed is set when * &drm_crtc_state.active changes, which is used for DPMS. + * &drm_crtc_state.no_vblank is set from the result of drm_dev_has_vblank(). * See also: drm_atomic_crtc_needs_modeset() * * IMPORTANT: @@ -649,6 +650,11 @@ drm_atomic_helper_check_modeset(struct drm_device *dev, return -EINVAL; } + + if (drm_dev_has_vblank(dev)) + new_crtc_state->no_vblank = false; + else + new_crtc_state->no_vblank = true; } ret = handle_conflicting_encoders(state, false); @@ -2215,7 +2221,9 @@ EXPORT_SYMBOL(drm_atomic_helper_wait_for_dependencies); * when a job is queued, and any change to the pipeline that does not touch the * connector is leading to timeouts when calling * drm_atomic_helper_wait_for_vblanks() or - * drm_atomic_helper_wait_for_flip_done(). + * drm_atomic_helper_wait_for_flip_done(). In addition to writeback + * connectors, this function can also fake VBLANK events for CRTCs without + * VBLANK interrupt. * * This is part of the atomic helper support for nonblocking commits, see * drm_atomic_helper_setup_commit() for an overview. diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c index 1659b13b178c..27a99c486f02 100644 --- a/drivers/gpu/drm/drm_vblank.c +++ b/drivers/gpu/drm/drm_vblank.c @@ -69,6 +69,12 @@ * &drm_driver.max_vblank_count. In that case the vblank core only disables the * vblanks after a timer has expired, which can be configured through the * ``vblankoffdelay`` module parameter. + * + * Drivers for hardware without support for vertical-blanking interrupts + * must not call drm_vblank_init(). For such drivers, atomic helpers will + * automatically generate fake vblank events as part of the display update. + * This functionality also can be controlled by the driver by enabling and + * disabling struct drm_crtc_state.no_vblank. */ /* Retry timestamp calculation up to 3 times to satisfy @@ -501,6 +507,28 @@ int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs) } EXPORT_SYMBOL(drm_vblank_init); +/** + * drm_dev_has_vblank - test if vblanking has been initialized for + * a device + * @dev: the device + * + * Drivers may call this function to test if vblank support is + * initialized for a device. For most hardware this means that vblanking + * can also be enabled. + * + * Atomic helpers use this function to initialize + * &drm_crtc_state.no_vblank. See also drm_atomic_helper_check_modeset(). + * + * Returns: + * True if vblanking has been initialized for the given device, false + * otherwise. + */ +bool drm_dev_has_vblank(const struct drm_device *dev) +{ + return dev->num_crtcs != 0; +} +EXPORT_SYMBOL(drm_dev_has_vblank); + /** * drm_crtc_vblank_waitqueue - get vblank waitqueue for the CRTC * @crtc: which CRTC's vblank waitqueue to retrieve diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index 5e9b15a0e8c5..6bef2f41d4d7 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -174,12 +174,25 @@ struct drm_crtc_state { * @no_vblank: * * Reflects the ability of a CRTC to send VBLANK events. This state - * usually depends on the pipeline configuration, and the main usuage - * is CRTCs feeding a writeback connector operating in oneshot mode. - * In this case the VBLANK event is only generated when a job is queued - * to the writeback connector, and we want the core to fake VBLANK - * events when this part of the pipeline hasn't changed but others had - * or when the CRTC and connectors are being disabled. + * usually depends on the pipeline configuration. If set to true, DRM + * atomic helpers will send out a fake VBLANK event during display + * updates after all hardware changes have been committed. This is + * implemented in drm_atomic_helper_fake_vblank(). + * + * One usage is for drivers and/or hardware without support for VBLANK + * interrupts. Such drivers typically do not initialize vblanking + * (i.e., call drm_vblank_init() with the number of CRTCs). For CRTCs + * without initialized vblanking, this field is set to true in + * drm_atomic_helper_check_modeset(), and a fake VBLANK event will be + * send out on each update of the display pipeline by + * drm_atomic_helper_fake_vblank(). + * + * Another usage is CRTCs feeding a writeback connector operating in + * oneshot mode. In this case the fake VBLANK event is only generated + * when a job is queued to the writeback connector, and we want the + * core to fake VBLANK events when this part of the pipeline hasn't + * changed but others had or when the CRTC and connectors are being + * disabled. * * __drm_atomic_helper_crtc_duplicate_state() will not reset the value * from the current state, the CRTC driver is then responsible for @@ -335,7 +348,14 @@ struct drm_crtc_state { * - Events for disabled CRTCs are not allowed, and drivers can ignore * that case. * - * This can be handled by the drm_crtc_send_vblank_event() function, + * For very simple hardware without VBLANK interrupt, enabling + * &struct drm_crtc_state.no_vblank makes DRM's atomic commit helpers + * send a fake VBLANK event at the end of the display update after all + * hardware changes have been applied. See + * drm_atomic_helper_fake_vblank(). + * + * For more complex hardware this + * can be handled by the drm_crtc_send_vblank_event() function, * which the driver should call on the provided event upon completion of * the atomic commit. Note that if the driver supports vblank signalling * and timestamping the vblank counters and timestamps must agree with diff --git a/include/drm/drm_simple_kms_helper.h b/include/drm/drm_simple_kms_helper.h index 15afee9cf049..e253ba7bea9d 100644 --- a/include/drm/drm_simple_kms_helper.h +++ b/include/drm/drm_simple_kms_helper.h @@ -100,8 +100,11 @@ struct drm_simple_display_pipe_funcs { * This is the function drivers should submit the * &drm_pending_vblank_event from. Using either * drm_crtc_arm_vblank_event(), when the driver supports vblank - * interrupt handling, or drm_crtc_send_vblank_event() directly in case - * the hardware lacks vblank support entirely. + * interrupt handling, or drm_crtc_send_vblank_event() for more + * complex case. In case the hardware lacks vblank support entirely, + * drivers can set &struct drm_crtc_state.no_vblank in + * &struct drm_simple_display_pipe_funcs.check and let DRM's + * atomic helper fake a vblank event. */ void (*update)(struct drm_simple_display_pipe *pipe, struct drm_plane_state *old_plane_state); diff --git a/include/drm/drm_vblank.h b/include/drm/drm_vblank.h index c16c44052b3d..94275e93fd27 100644 --- a/include/drm/drm_vblank.h +++ b/include/drm/drm_vblank.h @@ -206,6 +206,7 @@ struct drm_vblank_crtc { }; int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs); +bool drm_dev_has_vblank(const struct drm_device *dev); u64 drm_crtc_vblank_count(struct drm_crtc *crtc); u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc, ktime_t *vblanktime);