Re: [PATCH 0/2] drm/atomic: Allow drivers to write their own plane check for async

[André Almeida]

+ Joshua

Em 16/01/2024 10:14, Pekka Paalanen escreveu:
> On Tue, 16 Jan 2024 08:50:59 -0300
> André Almeida <andrealmeid@xxxxxxxxxx> wrote:
>
> > Hi Pekka,
> >
> > Em 16/01/2024 06:45, Pekka Paalanen escreveu:
> > > On Tue, 16 Jan 2024 01:51:57 -0300
> > > André Almeida <andrealmeid@xxxxxxxxxx> wrote:
> > >    
> > > > Hi,
> > > >
> > > > AMD hardware can do more on the async flip path than just the primary plane, so
> > > > to lift up the current restrictions, this patchset allows drivers to write their
> > > > own check for planes for async flips.
> > >
> > > Hi,
> > >
> > > what's the userspace story for this, how could userspace know it could do more?
> > > What kind of userspace would take advantage of this and in what situations?
> > >
> > > Or is this not meant for generic userspace?
> >
> > Sorry, I forgot to document this. So the idea is that userspace will
> > query what they can do here with DRM_MODE_ATOMIC_TEST_ONLY calls,
> > instead of having capabilities for each prop.
>
> That's the theory, but do you have a practical example?
>
> What other planes and props would one want change in some specific use
> case?
>
> Is it just "all or nothing", or would there be room to choose and pick
> which props you change and which you don't based on what the driver
> supports? If the latter, then relying on TEST_ONLY might be yet another
> combinatorial explosion to iterate through.

That's a good question, maybe Simon, Xaver or Joshua can share how they 
were planning to use this on Gamescope or Kwin.

> Thanks,
> pq
>
> > > > I'm not sure if adding something new to drm_plane_funcs is the right way to do,
> > > > because if we want to expand the other object types (crtc, connector) we would
> > > > need to add their own drm_XXX_funcs, so feedbacks are welcome!
> > > >
> > > > 	André
> > > >
> > > > André Almeida (2):
> > > >     drm/atomic: Allow drivers to write their own plane check for async
> > > >       flips
> > > >     drm/amdgpu: Implement check_async_props for planes
> > > >
> > > >    .../amd/display/amdgpu_dm/amdgpu_dm_plane.c   | 30 +++++++++
> > > >    drivers/gpu/drm/drm_atomic_uapi.c             | 62 ++++++++++++++-----
> > > >    include/drm/drm_atomic_uapi.h                 | 12 ++++
> > > >    include/drm/drm_plane.h                       |  5 ++
> > > >    4 files changed, 92 insertions(+), 17 deletions(-)
> > > >   
> > >