drm: Skip the waitqueue setup for vblank queries (82c8e025) · Commits · 戴 / test

Avoid adding to the waitqueue and reprobing the current vblank if the caller is only querying the current vblank sequence and timestamp, where we know that the wait would return immediately. v2: Add CRTC identifier to debug messages Signed-off-by:

Chris Wilson <chris@chris-wilson.co.uk> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Michel Dänzer <michel@daenzer.net> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Dave Airlie <airlied@redhat.com>, Cc: Mario Kleiner <mario.kleiner.de@gmail.com> Reviewed-by:

Michel Dänzer <michel@daenzer.net> Reviewed-and-tested-by:

Mario Kleiner <mario.kleiner.de@gmail.com> Signed-off-by:

Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/20170315204027.20160-2-chris@chris-wilson.co.uk

drivers/gpu/drm/drm_irq.c

+13 −11

Original line number	Diff line number	Diff line
		@@ -1610,7 +1610,7 @@ int drm_wait_vblank(struct drm_device dev, void data,

		ret = drm_vblank_get(dev, pipe);
		if (ret) {
		DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
		DRM_DEBUG("crtc %d failed to acquire vblank counter, %d\n", pipe, ret);
		return ret;
		}
		seq = drm_vblank_count(dev, pipe);
		@@ -1638,6 +1638,7 @@ int drm_wait_vblank(struct drm_device dev, void data,
		return drm_queue_vblank_event(dev, pipe, vblwait, file_priv);
		}

		if (vblwait->request.sequence != seq) {
		DRM_DEBUG("waiting on vblank count %u, crtc %u\n",
		vblwait->request.sequence, pipe);
		DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
		@@ -1645,6 +1646,7 @@ int drm_wait_vblank(struct drm_device dev, void data,
		vblwait->request.sequence) <= (1 << 23)) \|\|
		!vblank->enabled \|\|
		!dev->irq_enabled));
		}

		if (ret != -EINTR) {
		struct timeval now;
		@@ -1653,10 +1655,10 @@ int drm_wait_vblank(struct drm_device dev, void data,
		vblwait->reply.tval_sec = now.tv_sec;
		vblwait->reply.tval_usec = now.tv_usec;

		DRM_DEBUG("returning %u to client\n",
		vblwait->reply.sequence);
		DRM_DEBUG("crtc %d returning %u to client\n",
		pipe, vblwait->reply.sequence);
		} else {
		DRM_DEBUG("vblank wait interrupted by signal\n");
		DRM_DEBUG("crtc %d vblank wait interrupted by signal\n", pipe);
		}

		done:

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