Re: [PATCH v12 2/2] drm/amdgpu: Enable async flip on overlay planes

[André Almeida]

Em 29/01/2025 11:36, Xaver Hugl escreveu:
> Am Mo., 27. Jan. 2025 um 21:00 Uhr schrieb André Almeida
> <andrealmeid@xxxxxxxxxx>:
> > amdgpu can handle async flips on overlay planes, so allow it for atomic
> > async checks.
> >
> > Signed-off-by: André Almeida <andrealmeid@xxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c | 10 ++++++----
> >   1 file changed, 6 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
> > index 774cc3f4f3fd9a964fe48c66eb596d2f6dfee602..6bfed3d1530e6610eea025b477f409ee505870da 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
> > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
> > @@ -1258,21 +1258,23 @@ static int amdgpu_dm_plane_atomic_check(struct drm_plane *plane,
> >   }
> >
> >   static int amdgpu_dm_plane_atomic_async_check(struct drm_plane *plane,
> > -                                             struct drm_atomic_state *state)
> > +                                             struct drm_atomic_state *state, bool flip)
> >   {
> >          struct drm_crtc_state *new_crtc_state;
> >          struct drm_plane_state *new_plane_state;
> >          struct dm_crtc_state *dm_new_crtc_state;
> >
> > -       /* Only support async updates on cursor planes. */
> > -       if (plane->type != DRM_PLANE_TYPE_CURSOR)
> > +       if (flip) {
> > +               if (plane->type != DRM_PLANE_TYPE_OVERLAY)
> > +                       return -EINVAL;
> > +       } else if (plane->type != DRM_PLANE_TYPE_CURSOR)
> >                  return -EINVAL;
>
> This changes the logic for cursor updates, flipping on the cursor
> plane allowed async updates before. Is that intentional?

It's not the intention of this patch to disable async updates on cursor 
planes... but I don't think it's happening here? Async plane updates and 
async page flips are different things.

Any function that used to call amdgpu_dm_plane_atomic_async_check() for 
an async update on a cursor plane will continue to being able to do that.

For callers of _atomic_async_check() from a page flip path (like 
drm_atomic_set_property()), those couldn't flip a cursor plane, and will 
continue to be like that for now.

At least this is my analysis, please let me know if I got something wrong.