On 30.06.26 18:57, Melissa Wen wrote:

On 30/06/2026 10:42, 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, like Wayland
compositors and drm_info, enable the client cap on sich drivers they will be
left without both color pipeline and the legacy properties COLOR_ENCODING and
COLOR_RANGE, effectively breaking YUV->RGB conversion support.

Add a new driver feature and guard the client cap behind it, allowing
plane color pipeline and legacy YUV->RGB support to co-exist.

Ouch, that's indeed a problem. Nice catch!

I'm not sure if this is the right way to go because plane color pipeline can be supported per plane and per hw family.
My suggestion would be to only deprecate COLOR_ENCODING and COLOR_RANGE in drm_mode_object_get_properties() if a plane COLOR_PIPELINE property is attached.
WDYT?

Hi Melissa!

I don't think we need or should use the legacy properties for drivers and clients that supports the new API. Once Harrys YUV conversion colorop series(1) lands, every plane on every hardware currently supporting COLOR_ENCODING and COLOR_RANGE could express that with the colorop API as well - even if not supporting any other operations. It would look roughly like this:

└───"COLOR_PIPELINE" (atomic): enum {Bypass, YUV Pipeline 123} = Bypass
    ├───Bypass
    └───YUV Pipeline 123
        └───Color Operation 123
            └───Properties
                ├───"TYPE" (immutable): enum {1D Curve, 1D LUT, 3x4 Matrix, Multiplier, 3D LUT, Fixed Matrix} = Fixed Matrix
                ├───"BYPASS" (atomic): range [0, 1] = 1
                ├───"NEXT" (atomic, immutable): object colorop = 465
                └───"FIXED_MATRIX_TYPE" (atomic): enum {YCbCr 601 Full to RGB, YCbCr 601 Limited to RGB, YCbCr 709 Full to RGB, YCbCr 709 Limited to RGB, YCbCr 2020 NC Full to RGB, YCbCr 2020 NC Limited to RGB} = YCbCr 601 Full to RGB

Doing so will be nicer for compositors/clients going forward as they'd only need to support a single API if they don't care about legacy drivers (and we can adapt all in-tree drivers).

Do you agree?

Best regards

Robert

1: https://lists.freedesktop.org/archives/dri-devel/2026-June/575655.html

P.S.: sorry for the noise, just resending with all to/cc headers to make sure it doesn't get lost - and wanted to add that I'm currently working on the Weston implementation for the YUV conversion colorop to get it over the line.

-- 
Robert Mader
Consultant Software Developer 

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