[Intel-gfx] [PATCH 01/21] drm: Add Enhanced Gamma and color lut range attributes

Pekka Paalanen ppaalanen at gmail.com
Wed Jun 2 09:33:35 UTC 2021


On Tue,  1 Jun 2021 16:21:58 +0530
Uma Shankar <uma.shankar at intel.com> wrote:

> Existing LUT precision structure is having only 16 bit
> precision. This is not enough for upcoming enhanced hardwares
> and advance usecases like HDR processing. Hence added a new
> structure with 32 bit precision values.
> 
> This also defines a new structure to define color lut ranges,
> along with related macro definitions and enums. This will help
> describe multi segmented lut ranges in the hardware.
> 
> Signed-off-by: Uma Shankar <uma.shankar at intel.com>
> ---
>  include/uapi/drm/drm_mode.h | 58 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 58 insertions(+)
> 
> diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
> index 9b6722d45f36..d0ce48d2e732 100644
> --- a/include/uapi/drm/drm_mode.h
> +++ b/include/uapi/drm/drm_mode.h
> @@ -819,6 +819,64 @@ struct hdr_output_metadata {
>  	};
>  };
>  
> +/*
> + * DRM_MODE_LUT_GAMMA|DRM_MODE_LUT_DEGAMMA is legal and means the LUT
> + * can be used for either purpose, but not simultaneously. To expose
> + * modes that support gamma and degamma simultaneously the gamma mode
> + * must declare distinct DRM_MODE_LUT_GAMMA and DRM_MODE_LUT_DEGAMMA
> + * ranges.
> + */
> +/* LUT is for gamma (after CTM) */
> +#define DRM_MODE_LUT_GAMMA BIT(0)
> +/* LUT is for degamma (before CTM) */
> +#define DRM_MODE_LUT_DEGAMMA BIT(1)
> +/* linearly interpolate between the points */
> +#define DRM_MODE_LUT_INTERPOLATE BIT(2)
> +/*
> + * the last value of the previous range is the
> + * first value of the current range.
> + */
> +#define DRM_MODE_LUT_REUSE_LAST BIT(3)
> +/* the curve must be non-decreasing */
> +#define DRM_MODE_LUT_NON_DECREASING BIT(4)
> +/* the curve is reflected across origin for negative inputs */
> +#define DRM_MODE_LUT_REFLECT_NEGATIVE BIT(5)
> +/* the same curve (red) is used for blue and green channels as well */
> +#define DRM_MODE_LUT_SINGLE_CHANNEL BIT(6)
> +
> +struct drm_color_lut_range {
> +	/* DRM_MODE_LUT_* */
> +	__u32 flags;
> +	/* number of points on the curve */
> +	__u16 count;
> +	/* input/output bits per component */
> +	__u8 input_bpc, output_bpc;
> +	/* input start/end values */
> +	__s32 start, end;
> +	/* output min/max values */
> +	__s32 min, max;
> +};
> +
> +enum lut_type {

Unprefixed type name in UAPI headers is probably not a good idea.

> +	LUT_TYPE_DEGAMMA = 0,
> +	LUT_TYPE_GAMMA = 1,
> +};

All the above stuff seems to be the same in your other patch series'
patch "[PATCH 1/9] drm: Add gamma mode property". Is this series
replacing the series "[PATCH 0/9] Enhance pipe color support for multi
segmented luts" or what does this mean?


Thanks,
pq

> +
> +/*
> + * Creating 64 bit palette entries for better data
> + * precision. This will be required for HDR and
> + * similar color processing usecases.
> + */
> +struct drm_color_lut_ext {
> +	/*
> +	 * Data is U32.32 fixed point format.
> +	 */
> +	__u64 red;
> +	__u64 green;
> +	__u64 blue;
> +	__u64 reserved;
> +};
> +
>  #define DRM_MODE_PAGE_FLIP_EVENT 0x01
>  #define DRM_MODE_PAGE_FLIP_ASYNC 0x02
>  #define DRM_MODE_PAGE_FLIP_TARGET_ABSOLUTE 0x4

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