Re: [PATCH v3] drm: Guard DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE

[Borah, Chaitanya Kumar]

On 7/7/2026 6:31 PM, Maarten Lankhorst wrote:
> Hey,
>
> On 7/7/26 10:03, Borah, Chaitanya Kumar wrote:
> > On 7/3/2026 1:02 PM, Robert Mader wrote:
> > > The client cap is currently advertised unconditionally, even for drivers
> > > that do not support plane color pipelines. If clients supporting the later,
> > s/later/latter
> >
> > > like Wayland compositors or tools like drm_info, enable the client cap on
> > > such drivers they will be left without both color pipeline and the legacy
> > > properties COLOR_ENCODING and COLOR_RANGE, effectively breaking YUV->RGB
> > > conversion support.
> > >
> > > Prevent that by only marking the cap supported if there are actually planes
> > > with color pipelines.
> > >
> > > Note: while the color pipeline replacement for the legacy properties is
> > > still under review (1), we can assume that it will work as a drop-in
> > > replacement.
> > This change will but a driver can also choose to export colorops like programmable CTM_3x4 to achieve the same.
> >
> > We should also perhaps document this somewhere that if a driver supports LEGACY properties, it is imperative to implement some version of it with the color pipeline line property.
> Would this be doable inside drm core? Implement the color pipeline properties, get the fixed pipeline for free?

Right now, the Bypass(default) pipeline is automatically created when we 
call drm_plane_create_color_pipeline_property(), we could come up with a 
similar helper that could also create a pipeline that replaces the 
legacy properties.

But this can't replace the existing helper entirely because some HW 
(though unlikely) might not support YUV buffers.

==
Chaitanya