Hi Ville, On 10.10.2017 15:33, 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> > --- > 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; With this patch drm_crtc_arm_vblank_event calls drm_crtc_accurate_vblank_count, which requires get_vblank_timestamp callback, otherwise it issue WARN every time it is called. On the other side most of the users of drm_crtc_arm_vblank_event do not implement this callback. As a result one can observe multiple WARNs. It was observed on Exynos platform but grep shows it can affect many other platforms: $ git grep -l drm_crtc_arm_vblank_event drivers/gpu/drm/ drivers/gpu/drm/arm/hdlcd_crtc.c drivers/gpu/drm/arm/malidp_drv.c drivers/gpu/drm/drm_vblank.c drivers/gpu/drm/exynos/exynos_drm_crtc.c drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c drivers/gpu/drm/hisilicon/kirin/kirin_drm_ade.c drivers/gpu/drm/i915/intel_sprite.c drivers/gpu/drm/imx/ipuv3-crtc.c drivers/gpu/drm/mxsfb/mxsfb_crtc.c drivers/gpu/drm/nouveau/nouveau_display.c drivers/gpu/drm/pl111/pl111_display.c drivers/gpu/drm/sti/sti_crtc.c drivers/gpu/drm/stm/ltdc.c drivers/gpu/drm/sun4i/sun4i_crtc.c drivers/gpu/drm/tve200/tve200_display.c drivers/gpu/drm/vmwgfx/vmwgfx_kms.c drivers/gpu/drm/zte/zx_vou.c $ git grep -l get_vblank_timestamp drivers/gpu/drm/ drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c drivers/gpu/drm/drm_vblank.c drivers/gpu/drm/i915/i915_irq.c drivers/gpu/drm/msm/mdp/mdp5/mdp5_kms.c drivers/gpu/drm/nouveau/nouveau_drm.c drivers/gpu/drm/radeon/radeon_drv.c drivers/gpu/drm/vc4/vc4_drv.c Regards Andrzej > e->event.crtc_id = crtc->base.id; > list_add_tail(&e->base.link, &dev->vblank_event_list); > } _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
