[RFC PATCH 1/3] drm: Introduce color fill properties for drm plane

[Simon Ser]

On Saturday, October 29th, 2022 at 13:23, Dmitry Baryshkov <dmitry.baryshkov at linaro.org> wrote:

> On 29/10/2022 01:59, Jessica Zhang wrote:
> 
> > Add support for COLOR_FILL and COLOR_FILL_FORMAT properties for
> > drm_plane. In addition, add support for setting and getting the values
> > of these properties.
> > 
> > COLOR_FILL represents the color fill of a plane while COLOR_FILL_FORMAT
> > represents the format of the color fill. Userspace can set enable solid
> > fill on a plane by assigning COLOR_FILL to a uint64_t value, assigning
> > the COLOR_FILL_FORMAT property to a uint32_t value, and setting the
> > framebuffer to NULL.
> 
> I suppose that COLOR_FILL should override framebuffer rather than
> requiring that FB is set to NULL. In other words, if color_filL_format
> is non-zero, it would make sense to ignore the FB. Then one can use the
> color_fill_format property to quickly switch between filled plane and
> FB-backed one.

That would be inconsistent with the rest of the KMS uAPI. For instance,
the kernel will error out if CRTC has active=0 but a connector is still
linked to the CRTC. IOW, the current uAPI errors out if the KMS state
is inconsistent.