From 4c684596cde44d03dfd9624c86e1de4db0dcf121 Mon Sep 17 00:00:00 2001 From: Cristian Ciocaltea Date: Tue, 3 Mar 2026 21:24:18 +0200 Subject: drm: Add CRTC background color property MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Some display controllers can be hardware programmed to show non-black colors for pixels that are either not covered by any plane or are exposed through transparent regions of higher planes. This feature can help reduce memory bandwidth usage, e.g. in compositors managing a UI with a solid background color while using smaller planes to render the remaining content. To support this capability, introduce the BACKGROUND_COLOR standard DRM mode property, which can be attached to a CRTC through the drm_crtc_attach_background_color_property() helper function. Additionally, define a 64-bit ARGB format value to be built with the help of a couple of dedicated DRM_ARGB64_PREP*() helpers. Individual color components can be extracted with desired precision using the corresponding DRM_ARGB64_GET*() macros. Co-developed-by: Matt Roper Signed-off-by: Matt Roper Reviewed-by: Nícolas F. R. A. Prado Tested-by: Diederik de Haas Signed-off-by: Cristian Ciocaltea Link: https://patch.msgid.link/20260303-rk3588-bgcolor-v8-2-fee377037ad1@collabora.com Signed-off-by: Daniel Stone --- include/drm/drm_blend.h | 4 +++- include/drm/drm_crtc.h | 12 ++++++++++++ include/drm/drm_mode_config.h | 5 +++++ 3 files changed, 20 insertions(+), 1 deletion(-) (limited to 'include/drm') diff --git a/include/drm/drm_blend.h b/include/drm/drm_blend.h index 88bdfec3bd88..c7e888767c81 100644 --- a/include/drm/drm_blend.h +++ b/include/drm/drm_blend.h @@ -31,8 +31,9 @@ #define DRM_MODE_BLEND_COVERAGE 1 #define DRM_MODE_BLEND_PIXEL_NONE 2 -struct drm_device; struct drm_atomic_state; +struct drm_crtc; +struct drm_device; struct drm_plane; static inline bool drm_rotation_90_or_270(unsigned int rotation) @@ -58,4 +59,5 @@ int drm_atomic_normalize_zpos(struct drm_device *dev, struct drm_atomic_state *state); int drm_plane_create_blend_mode_property(struct drm_plane *plane, unsigned int supported_modes); +void drm_crtc_attach_background_color_property(struct drm_crtc *crtc); #endif diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index 66278ffeebd6..312fc1e745d2 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -274,6 +274,18 @@ struct drm_crtc_state { */ struct drm_property_blob *gamma_lut; + /** + * @background_color: + * + * RGB value representing the CRTC's background color. The background + * color (aka "canvas color") of a CRTC is the color that will be used + * for pixels not covered by a plane, or covered by transparent pixels + * of a plane. The value here should be built using DRM_ARGB64_PREP*() + * helpers, while the individual color components can be extracted with + * desired precision via the DRM_ARGB64_GET*() macros. + */ + u64 background_color; + /** * @target_vblank: * diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h index 5e1dd0cfccde..687c0ee163d2 100644 --- a/include/drm/drm_mode_config.h +++ b/include/drm/drm_mode_config.h @@ -836,6 +836,11 @@ struct drm_mode_config { * gamma LUT as supported by the driver (read-only). */ struct drm_property *gamma_lut_size_property; + /** + * @background_color_property: Optional CRTC property to set the + * background color. + */ + struct drm_property *background_color_property; /** * @suggested_x_property: Optional connector property with a hint for -- cgit v1.2.3