Commit 5f87e090 authored Jul 17, 2014 by Mario Kleiner Committed by Alex Deucher Jul 17, 2014

drm/radeon: Make classic pageflip completion path less racy.



Need to protect mmio flip programming by event lock as well.

Need to also first enable pflip irq, then mmio program,
otherwise a flip completion may get unnoticed in the vblank
of actual completion if the flip is programmed, but
radeon_flip_work_func gets preempted immediately after
mmio programming and before vblank. In that case the
vblank irq handler wouldn't run radeon_crtc_handle_vblank()
with the completion check routine, miss the completed flip,
and only notice one vblank after actual completion, causing
a false/delayed report of flip completion.

Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

parent 82648497

drivers/gpu/drm/radeon/radeon_display.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -407,15 +407,15 @@ static void radeon_flip_work_func(struct work_struct *__work)
		radeon_fence_unref(&work->fence);
		}

		/* do the flip (mmio) */
		radeon_page_flip(rdev, radeon_crtc->crtc_id, work->base);

		/* We borrow the event spin lock for protecting flip_status */
		spin_lock_irqsave(&crtc->dev->event_lock, flags);

		/* set the proper interrupt */
		radeon_irq_kms_pflip_irq_get(rdev, radeon_crtc->crtc_id);

		/* do the flip (mmio) */
		radeon_page_flip(rdev, radeon_crtc->crtc_id, work->base);

		radeon_crtc->flip_status = RADEON_FLIP_SUBMITTED;
		spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
		up_read(&rdev->exclusive_lock);