[PATCH] drm/doc: Interlink color manager docs better

[Lionel Landwerlin]

I have a tiny suggestion down there. Regardless this is :

Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>

On 12/04/17 08:20, Daniel Vetter wrote:
> Motivated by a request from Eric.
>
> Cc: Eric Anholt <eric at anholt.net>
> Cc: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> ---
>   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().

Maybe you can add that the blob is either NULL or an array of drm_color_lut.

> +	 */
>   	struct drm_property_blob *degamma_lut;
> +
> +	/**
> +	 * @ctm:
> +	 *
> +	 * Color transformation matrix. See drm_crtc_enable_color_mgmt().

Here is blob is drm_color_ctm.

> +	 */
>   	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().

Here again NULL or an array of drm_color_lut.

> +	 */
>   	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