From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> On machines where the vblank interrupt fires some time after the start of vblank (or we just manage to race with the vblank interrupt handler) we will currently stuff a stale vblank counter value into the flip event, and thus we'll prematurely complete the flip. Switch over to drm_crtc_accurate_vblank_count() to make sure we have an up to date counter value, crucially also remember to add the +1 so that the delayed vblank interrupt won't complete the flip prematurely. Cc: stable@xxxxxxxxxxxxxxx Cc: Daniel Vetter <daniel@xxxxxxxx> Suggested-by: Daniel Vetter <daniel@xxxxxxxx> Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> --- drivers/gpu/drm/drm_vblank.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c index 70f2b9593edc..f14e6c92e332 100644 --- a/drivers/gpu/drm/drm_vblank.c +++ b/drivers/gpu/drm/drm_vblank.c @@ -869,7 +869,7 @@ void drm_crtc_arm_vblank_event(struct drm_crtc *crtc, assert_spin_locked(&dev->event_lock); e->pipe = pipe; - e->event.sequence = drm_vblank_count(dev, pipe); + e->event.sequence = drm_crtc_accurate_vblank_count(crtc) + 1; e->event.crtc_id = crtc->base.id; list_add_tail(&e->base.link, &dev->vblank_event_list); } -- 2.13.6