From patchwork Sat Nov 21 00:37:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Veera Sundaram Sankaran X-Patchwork-Id: 330513 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A559CC5519F for ; Sat, 21 Nov 2020 00:37:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7841C24137 for ; Sat, 21 Nov 2020 00:37:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728776AbgKUAhV (ORCPT ); Fri, 20 Nov 2020 19:37:21 -0500 Received: from alexa-out-sd-02.qualcomm.com ([199.106.114.39]:20939 "EHLO alexa-out-sd-02.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727773AbgKUAhV (ORCPT ); Fri, 20 Nov 2020 19:37:21 -0500 Received: from unknown (HELO ironmsg01-sd.qualcomm.com) ([10.53.140.141]) by alexa-out-sd-02.qualcomm.com with ESMTP; 20 Nov 2020 16:37:20 -0800 X-QCInternal: smtphost Received: from veeras-linux.qualcomm.com ([10.134.68.137]) by ironmsg01-sd.qualcomm.com with ESMTP; 20 Nov 2020 16:37:19 -0800 Received: by veeras-linux.qualcomm.com (Postfix, from userid 330320) id C4A3221A89; Fri, 20 Nov 2020 16:37:19 -0800 (PST) From: Veera Sundaram Sankaran To: dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, sumit.semwal@linaro.org, gustavo@padovan.org, airlied@linux.ie, daniel@ffwll.ch Cc: Veera Sundaram Sankaran , robdclark@gmail.com, sean@poorly.run, pdhaval@codeaurora.org, abhinavk@codeaurora.org, jsanka@codeaurora.org Subject: [PATCH v2 2/2] drm/drm_vblank: set the dma-fence timestamp during send_vblank_event Date: Fri, 20 Nov 2020 16:37:14 -0800 Message-Id: <1605919034-15065-2-git-send-email-veeras@codeaurora.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1605919034-15065-1-git-send-email-veeras@codeaurora.org> References: <1605919034-15065-1-git-send-email-veeras@codeaurora.org> Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org The explicit out-fences in crtc are signaled as part of vblank event, indicating all framebuffers present on the Atomic Commit request are scanned out on the screen. Though the fence signal and the vblank event notification happens at the same time, triggered by the same hardware vsync event, the timestamp set in both are different. With drivers supporting precise vblank timestamp the difference between the two timestamps would be even higher. This might have an impact on use-mode frameworks using these fence timestamps for purposes other than simple buffer usage. For instance, the Android framework [1] uses the retire-fences as an alternative to vblank when frame-updates are in progress. Set the fence timestamp during send vblank event using a new drm_send_event_timestamp_locked variant to avoid discrepancies. [1] https://android.googlesource.com/platform/frameworks/native/+/master/ services/surfaceflinger/Scheduler/Scheduler.cpp#397 Changes in v2: - Use drm_send_event_timestamp_locked to update fence timestamp - add more information to commit text Signed-off-by: Veera Sundaram Sankaran --- drivers/gpu/drm/drm_file.c | 43 +++++++++++++++++++++++++++++++++++++++++++ drivers/gpu/drm/drm_vblank.c | 9 ++++++++- include/drm/drm_file.h | 3 +++ 3 files changed, 54 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c index 0ac4566..5944bb9 100644 --- a/drivers/gpu/drm/drm_file.c +++ b/drivers/gpu/drm/drm_file.c @@ -775,6 +775,49 @@ void drm_event_cancel_free(struct drm_device *dev, EXPORT_SYMBOL(drm_event_cancel_free); /** + * drm_send_event_timestamp_locked - send DRM event to file descriptor + * @dev: DRM device + * @e: DRM event to deliver + * @timestamp: timestamp to set for the fence event + * + * This function sends the event @e, initialized with drm_event_reserve_init(), + * to its associated userspace DRM file. Callers must already hold + * &drm_device.event_lock, see drm_send_event() for the unlocked version. + * + * Note that the core will take care of unlinking and disarming events when the + * corresponding DRM file is closed. Drivers need not worry about whether the + * DRM file for this event still exists and can call this function upon + * completion of the asynchronous work unconditionally. + */ +void drm_send_event_timestamp_locked(struct drm_device *dev, + struct drm_pending_event *e, ktime_t timestamp) +{ + assert_spin_locked(&dev->event_lock); + + if (e->completion) { + complete_all(e->completion); + e->completion_release(e->completion); + e->completion = NULL; + } + + if (e->fence) { + dma_fence_signal_timestamp(e->fence, timestamp); + dma_fence_put(e->fence); + } + + if (!e->file_priv) { + kfree(e); + return; + } + + list_del(&e->pending_link); + list_add_tail(&e->link, + &e->file_priv->event_list); + wake_up_interruptible(&e->file_priv->event_wait); +} +EXPORT_SYMBOL(drm_send_event_timestamp_locked); + +/** * drm_send_event_locked - send DRM event to file descriptor * @dev: DRM device * @e: DRM event to deliver diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c index b18e1ef..9899187 100644 --- a/drivers/gpu/drm/drm_vblank.c +++ b/drivers/gpu/drm/drm_vblank.c @@ -1000,7 +1000,14 @@ static void send_vblank_event(struct drm_device *dev, break; } trace_drm_vblank_event_delivered(e->base.file_priv, e->pipe, seq); - drm_send_event_locked(dev, &e->base); + /* + * Use the same timestamp for any associated fence signal to avoid + * mismatch in timestamps for vsync & fence events triggered by the + * same HW event. Frameworks like SurfaceFlinger in Android expects the + * retire-fence timestamp to match exactly with HW vsync as it uses it + * for its software vsync modeling. + */ + drm_send_event_timestamp_locked(dev, &e->base, now); } /** diff --git a/include/drm/drm_file.h b/include/drm/drm_file.h index 716990b..b81b3bf 100644 --- a/include/drm/drm_file.h +++ b/include/drm/drm_file.h @@ -399,6 +399,9 @@ void drm_event_cancel_free(struct drm_device *dev, struct drm_pending_event *p); void drm_send_event_locked(struct drm_device *dev, struct drm_pending_event *e); void drm_send_event(struct drm_device *dev, struct drm_pending_event *e); +void drm_send_event_timestamp_locked(struct drm_device *dev, + struct drm_pending_event *e, + ktime_t timestamp); struct file *mock_drm_getfile(struct drm_minor *minor, unsigned int flags);