Motivated by a request from Eric.
Cc: Eric Anholt <eric@xxxxxxxxxx>
Cc: Lionel Landwerlin <lionel.g.landwerlin@xxxxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
---
drivers/gpu/drm/drm_atomic_helper.c | 3 ++-
drivers/gpu/drm/drm_color_mgmt.c | 9 ++++++---
include/drm/drm_crtc.h | 31 +++++++++++++++++++++++++------
3 files changed, 33 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index c3403edd0285..442724a80010 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -3518,7 +3518,8 @@ EXPORT_SYMBOL(drm_atomic_helper_connector_destroy_state);
*
* Implements support for legacy gamma correction table for drivers
* that support color management through the DEGAMMA_LUT/GAMMA_LUT
- * properties.
+ * properties. See drm_crtc_enable_color_mgmt() and the containing chapter for
+ * how the atomic color management and gamma tables work.
*/
int drm_atomic_helper_legacy_gamma_set(struct drm_crtc *crtc,
u16 *red, u16 *green, u16 *blue,
diff --git a/drivers/gpu/drm/drm_color_mgmt.c b/drivers/gpu/drm/drm_color_mgmt.c
index 533f3a3e6877..3eda500fc005 100644
--- a/drivers/gpu/drm/drm_color_mgmt.c
+++ b/drivers/gpu/drm/drm_color_mgmt.c
@@ -43,7 +43,8 @@
*
* Setting this to NULL (blob property value set to 0) means a
* linear/pass-thru gamma table should be used. This is generally the
- * driver boot-up state too.
+ * driver boot-up state too. Drivers can access this blob through
+ * &drm_crtc_state.degamma_lut.
*
* “DEGAMMA_LUT_SIZE”:
* Unsinged range property to give the size of the lookup table to be set
@@ -60,7 +61,8 @@
*
* Setting this to NULL (blob property value set to 0) means a
* unit/pass-thru matrix should be used. This is generally the driver
- * boot-up state too.
+ * boot-up state too. Drivers can access the blob for the color conversion
+ * matrix through &drm_crtc_state.ctm.
*
* “GAMMA_LUT”:
* Blob property to set the gamma lookup table (LUT) mapping pixel data
@@ -72,7 +74,8 @@
*
* Setting this to NULL (blob property value set to 0) means a
* linear/pass-thru gamma table should be used. This is generally the
- * driver boot-up state too.
+ * driver boot-up state too. Drivers can access this blob through
+ * &drm_crtc_state.gamma_lut.
*
* “GAMMA_LUT_SIZE”:
* Unsigned range property to give the size of the lookup table to be set
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index a8176a836e25..60b128a9e723 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -93,11 +93,6 @@ struct drm_plane_helper_funcs;
* @adjusted_mode: for use by helpers and drivers to compute adjusted mode timings
* @mode: current mode timings
* @mode_blob: &drm_property_blob for @mode
- * @degamma_lut: Lookup table for converting framebuffer pixel data
- * before apply the conversion matrix
- * @ctm: Transformation matrix
- * @gamma_lut: Lookup table for converting pixel data after the
- * conversion matrix
* @state: backpointer to global drm_atomic_state
*
* Note that the distinction between @enable and @active is rather subtile:
@@ -144,9 +139,27 @@ struct drm_crtc_state {
/* blob property to expose current mode to atomic userspace */
struct drm_property_blob *mode_blob;
- /* blob property to expose color management to userspace */
+ /**
+ * @degamma_lut:
+ *
+ * Lookup table for converting framebuffer pixel data before apply the
+ * color conversion matrix @ctm. See drm_crtc_enable_color_mgmt().
+ */
struct drm_property_blob *degamma_lut;
+
+ /**
+ * @ctm:
+ *
+ * Color transformation matrix. See drm_crtc_enable_color_mgmt().
+ */
struct drm_property_blob *ctm;
+
+ /**
+ * @gamma_lut:
+ *
+ * Lookup table for converting pixel data after the color conversion
+ * matrix @ctm. See drm_crtc_enable_color_mgmt().
+ */
struct drm_property_blob *gamma_lut;
/**
@@ -313,6 +326,12 @@ struct drm_crtc_funcs {
*
* This callback is optional.
*
+ * Atomic drivers who want to support gamma tables should implement the
+ * atomic color management support, enabled by calling
+ * drm_crtc_enable_color_mgmt(), which then supports the legacy gamma
+ * interface through the drm_atomic_helper_legacy_gamma_set()
+ * compatibility implementation.
+ *
* NOTE:
*
* Drivers that support gamma tables and also fbdev emulation through
--
2.11.0
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