Hey,

On 07.07.26 10:26, Maarten Lankhorst wrote:
Hey,

This probably would be useful to backport to stable, can I add those tags and 
merge it?

yes, also please feel free to apply any suggestions by Chaitanyaand.

Thanks!


Fixes: 179ab8e7d7b3 ("drm/colorop: Introduce 
DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE")
Cc: <[email protected]> # v6.19+

Kind regards,
~Maarten Lankhorst

On 7/3/26 09:32, 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 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. That means any plane on any hardware currently supporting
the legacy properties will be able to offer a functionally equal color
pipeline and there will be no technical reason keep using the legacy
properties if both the driver and the client support the new API.

1: 
https://lore.kernel.org/dri-devel/[email protected]/

Signed-off-by: Robert Mader <[email protected]>

---

Changes in v3:
  - Move the new check behind the existing EINVAL ones
  - Rebase on latest drm-misc-next

Changes in v2:
  - Replace the driver feature with a simple check (suggested by Maarten
    Lankhorst <[email protected]>)
  - Expand the commit message slightly and change the title
---
  drivers/gpu/drm/drm_ioctl.c | 14 +++++++++++++-
  1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_ioctl.c b/drivers/gpu/drm/drm_ioctl.c
index e2df4becce62..9039a39c4324 100644
--- a/drivers/gpu/drm/drm_ioctl.c
+++ b/drivers/gpu/drm/drm_ioctl.c
@@ -373,13 +373,25 @@ drm_setclientcap(struct drm_device *dev, void *data, 
struct drm_file *file_priv)
                        return -EINVAL;
                file_priv->supports_virtualized_cursor_plane = req->value;
                break;
-       case DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE:
+       case DRM_CLIENT_CAP_PLANE_COLOR_PIPELINE: {
+               struct drm_plane *plane;
+               bool has_plane_with_color_pipeline = false;
+
                if (!file_priv->atomic)
                        return -EINVAL;
                if (req->value > 1)
                        return -EINVAL;
+               drm_for_each_plane(plane, dev) {
+                       if (plane->color_pipeline_property) {
+                               has_plane_with_color_pipeline = true;
+                               break;
+                       }
+               }
+               if (!has_plane_with_color_pipeline)
+                       return -EOPNOTSUPP;
                file_priv->plane_color_pipeline = req->value;
                break;
+       }
        default:
                return -EINVAL;
        }

--
Robert Mader
Consultant Software Developer

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