Re: [PATCH 1/8] display: fix blend_mode for non-overlay planes

[Joshua Peisach]

On Fri Aug 14, 2026 at 11:17 AM EDT, Bert Karwatzki wrote:
> Previously drm_plane_create_blend_mode_property() was only called for
> planes of type DRM_PLANE_TYPE_OVERLAY. Since commit commit 860e748bddcc
> ("drm: ensure blend mode supported if pixel format with alpha exposed")
> this results in warnings from validate_blend_mode_for_alpha_formats().
> We fix this here by calling drm_plane_create_blend_mode_property() for
> all plane types if the plane is supporting a format with
> per_pixel_alpha.
>
> Signed-off-by: Bert Karwatzki <spasswolf@xxxxxx>
> ---
>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c  | 5 ++++-
>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c | 3 +--
>  2 files changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
> index 62eac6e65334..a6a54351ea56 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_crtc.c
> @@ -755,13 +755,16 @@ int amdgpu_dm_crtc_init(struct amdgpu_display_manager *dm,
>  	struct drm_plane *cursor_plane;
>  	bool has_degamma;
>  	int res = -ENOMEM;
> +	struct dc_plane_cap dummy_cap = {
> +		.per_pixel_alpha = 1,
> +	};
>  
>  	cursor_plane = kzalloc_obj(*cursor_plane);
>  	if (!cursor_plane)
>  		goto fail;
>  
>  	cursor_plane->type = DRM_PLANE_TYPE_CURSOR;
> -	res = amdgpu_dm_plane_init(dm, cursor_plane, 0, NULL);
> +	res = amdgpu_dm_plane_init(dm, cursor_plane, 0, &dummy_cap);
>  
>  	acrtc = kzalloc_obj(struct amdgpu_crtc);
>  	if (!acrtc)
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
> index 824ef3ce5de0..4c0c6a8a0dac 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
> @@ -2208,8 +2208,7 @@ int amdgpu_dm_plane_init(struct amdgpu_display_manager *dm,
>  	if (res)
>  		return res;
>  
> -	if (plane->type == DRM_PLANE_TYPE_OVERLAY &&
> -	    plane_cap && plane_cap->per_pixel_alpha) {
> +	if (plane_cap && plane_cap->per_pixel_alpha) {
>  		unsigned int blend_caps = BIT(DRM_MODE_BLEND_PIXEL_NONE) |
>  					  BIT(DRM_MODE_BLEND_PREMULTI) |
>  					  BIT(DRM_MODE_BLEND_COVERAGE);

Not sure where the full patch set is, but this does make the warning
go away.

Tested-by: Joshua Peisach <jpeisach@xxxxxxxxxx>