On Tue, Oct 10, 2017 at 04:33:22PM +0300, Ville Syrjala wrote: > 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> Pushed to drm-misc-next with Daniel's irc r-b: 16:48 < danvet> vsyrjala, r-b, I think ... 17:31 < vsyrjala> danvet: your irc r-b for vblank_accurate+1 still holds? 17:32 < danvet> vsyrjala, yeah > --- > 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 -- Ville Syrjälä Intel OTC