From 7c33c32d39b9d11338624d4a7bad4e75bf64fbf8 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Tue, 10 Oct 2017 16:33:22 +0300 Subject: [PATCH] drm/vblank: Fix flip event vblank count MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit commit 632c6e4edef17c40bba3be67c980d959790d142f upstream. 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: Daniel Vetter Suggested-by: Daniel Vetter Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20171010133322.24029-1-ville.syrjala@linux.intel.com Reviewed-by: Daniel Vetter #irc Signed-off-by: Greg Kroah-Hartman --- 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); } -- 2.20.1