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authorDaniel Vetter <daniel.vetter@ffwll.ch>2022-01-24 23:16:33 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2022-01-25 09:36:20 +0100
commit4fd5e720b709b87f67809a871fde9fb6cb910f28 (patch)
treed71db39296e4770637771b6ef23d7bfadf38b389 /include/drm
parent8b250cd3b5da18bd90f34ecb04c01661213b65ba (diff)
drm/docs: Document where the C8 color lut is stored
Also add notes that for atomic drivers it's really somewhere else and no longer in struct drm_crtc. Maybe we should put a bigger warning here that this is confusing, since the pixel format is a plane property, but the GAMMA_LUT property is on the crtc. But I think we can fix this if/when someone finds a need for a per-plane CLUT, since I'm not sure such hw even exists. I'm also not sure whether even hardware with a CLUT and a full color correction pipeline with degamm/cgm/gamma exists. Motivated by comments from Geert that we have a gap here. v2: More names for color luts (Laurent). Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Thomas Zimmermann <tzimmermann@suse.de> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220124221633.952374-1-daniel.vetter@ffwll.ch
Diffstat (limited to 'include/drm')
-rw-r--r--include/drm/drm_crtc.h10
1 files changed, 10 insertions, 0 deletions
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 13eeba2a750a..f9f9af8b5448 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -285,6 +285,10 @@ struct drm_crtc_state {
* Lookup table for converting pixel data after the color conversion
* matrix @ctm. See drm_crtc_enable_color_mgmt(). The blob (if not
* NULL) is an array of &struct drm_color_lut.
+ *
+ * Note that for mostly historical reasons stemming from Xorg heritage,
+ * this is also used to store the color map (also sometimes color lut,
+ * CLUT or color palette) for indexed formats like DRM_FORMAT_C8.
*/
struct drm_property_blob *gamma_lut;
@@ -1075,12 +1079,18 @@ struct drm_crtc {
/**
* @gamma_size: Size of legacy gamma ramp reported to userspace. Set up
* by calling drm_mode_crtc_set_gamma_size().
+ *
+ * Note that atomic drivers need to instead use
+ * &drm_crtc_state.gamma_lut. See drm_crtc_enable_color_mgmt().
*/
uint32_t gamma_size;
/**
* @gamma_store: Gamma ramp values used by the legacy SETGAMMA and
* GETGAMMA IOCTls. Set up by calling drm_mode_crtc_set_gamma_size().
+ *
+ * Note that atomic drivers need to instead use
+ * &drm_crtc_state.gamma_lut. See drm_crtc_enable_color_mgmt().
*/
uint16_t *gamma_store;