[Intel-gfx] [PATCH] drm/atomic-helper: Don't set deadline for modesets

[Daniel Vetter]

On Wed, Apr 05, 2023 at 06:50:22AM -0700, Rob Clark wrote:
> On Wed, Apr 5, 2023 at 6:31 AM Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> >
> > If the crtc is being switched on or off then the semantics of
> > computing the timestampe of the next vblank is somewhat ill-defined.
> > And indeed, the code splats with a warning in the timestamp
> > computation code. Specifically it hits the check to make sure that
> > atomic drivers have full set up the timing constants in the drm_vblank
> > structure, and that's just not the case before the crtc is actually
> > on.
> >
> > For robustness it seems best to just not set deadlines for modesets.
> >
> > v2: Also skip on inactive crtc (Ville)
> >
> > Link: https://lore.kernel.org/dri-devel/dfc21f18-7e1e-48f0-c05a-d659b9c90b91@linaro.org/
> > Fixes: d39e48ca80c0 ("drm/atomic-helper: Set fence deadline for vblank")
> > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > Cc: Rob Clark <robdclark at chromium.org>
> > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> > Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > Cc: Maxime Ripard <mripard at kernel.org>
> > Cc: Thomas Zimmermann <tzimmermann at suse.de>
> > Reported-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> > Tested-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org> # test patch only
> > Cc: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
> > Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> 
> Reviewed-by: Rob Clark <robdclark at gmail.com>

Merged to drm-misc-next, thanks for review.

> 
> > ---
> >  drivers/gpu/drm/drm_atomic_helper.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> > index f21b5a74176c..d44fb9b87ef8 100644
> > --- a/drivers/gpu/drm/drm_atomic_helper.c
> > +++ b/drivers/gpu/drm/drm_atomic_helper.c
> > @@ -1528,6 +1528,12 @@ static void set_fence_deadline(struct drm_device *dev,
> >         for_each_new_crtc_in_state (state, crtc, new_crtc_state, i) {
> >                 ktime_t v;
> >
> > +               if (drm_atomic_crtc_needs_modeset(new_crtc_state))
> > +                       continue;
> > +
> > +               if (!new_crtc_state->active)
> > +                       continue;
> > +
> >                 if (drm_crtc_next_vblank_start(crtc, &v))
> >                         continue;
> >
> > --
> > 2.40.0
> >

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch