[PATCH] drm: don't run atomic_async_check for disabled planes

[Murthy, Arun R]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Alex
> Deucher
> Sent: Tuesday, July 29, 2025 12:30 AM
> To: Xaver Hugl <xaver.hugl at kde.org>
> Cc: dri-devel at lists.freedesktop.org; andrealmeid at igalia.com;
> chris at kode54.net; Kumar, Naveen1 <naveen1.kumar at intel.com>;
> ville.syrjala at linux.intel.com; mdaenzer at redhat.com; intel-
> gfx at lists.freedesktop.org; amd-gfx at lists.freedesktop.org
> Subject: Re: [PATCH] drm: don't run atomic_async_check for disabled planes
> 
> On Wed, Jul 23, 2025 at 11:08 AM Xaver Hugl <xaver.hugl at kde.org> wrote:
> >
> > It's entirely valid and correct for compositors to include disabled
> > planes in the atomic commit, and doing that should not prevent async
> > flips from working. To fix that, this commit skips the async checks if
> > the plane was and still is not visible.
> >
> > Fixes: fd40a63c drm/atomic: Let drivers decide which planes to async
> > flip
> 
> This should be:
> Fixes: fd40a63c63a1 ("drm/atomic: Let drivers decide which planes to async
> flip")
> 
> > Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4263
> >
> > Signed-off-by: Xaver Hugl <xaver.hugl at kde.org>
> > ---
> >  drivers/gpu/drm/drm_atomic_uapi.c | 10 +++++++++-
> >  1 file changed, 9 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/drm_atomic_uapi.c
> > b/drivers/gpu/drm/drm_atomic_uapi.c
> > index c2726af6698e..2e62561fd94d 100644
> > --- a/drivers/gpu/drm/drm_atomic_uapi.c
> > +++ b/drivers/gpu/drm/drm_atomic_uapi.c
> > @@ -1066,6 +1066,7 @@ int drm_atomic_set_property(struct
> drm_atomic_state *state,
> >         }
> >         case DRM_MODE_OBJECT_PLANE: {
> >                 struct drm_plane *plane = obj_to_plane(obj);
> > +               struct drm_plane_state *old_plane_state;
> >                 struct drm_plane_state *plane_state;
> >                 struct drm_mode_config *config = &plane->dev->mode_config;
> >                 const struct drm_plane_helper_funcs *plane_funcs =
> > plane->helper_private; @@ -1086,8 +1087,15 @@ int
> drm_atomic_set_property(struct drm_atomic_state *state,
> >                                 ret = drm_atomic_check_prop_changes(ret, old_val,
> prop_value, prop);
> >                         }
> >
> > +                       old_plane_state = drm_atomic_get_old_plane_state(state,
> plane);
> > +                       if (IS_ERR(old_plane_state)) {
> > +                               ret = PTR_ERR(plane_state);

This should be PTR_ERR(old_plane_state)

> > +                               break;
> > +                       }
> > +
> >                         /* ask the driver if this non-primary plane is supported */
> > -                       if (plane->type != DRM_PLANE_TYPE_PRIMARY) {
> > +                       if (plane->type != DRM_PLANE_TYPE_PRIMARY &&
> > +                                       (plane_state->visible ||
> > + old_plane_state->visible)) {
The present plane_state->visible will be updated based on the current list of properties in atomic_check() which is called after this set_property().
For ex in the present flip the FB is NULL then we disable the plane, the flag for doing this is done later in atomic_check().

Thanks and Regards,
Arun R Murthy
-------------------
> >                                 ret = -EINVAL;
> >
> >                                 if (plane_funcs &&
> > plane_funcs->atomic_async_check)
> > --
> > 2.50.1
> >