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

[Shankar, Uma]

> -----Original Message-----
> From: Pekka Paalanen <ppaalanen at gmail.com>
> Sent: Wednesday, June 2, 2021 3:04 PM
> To: Shankar, Uma <uma.shankar at intel.com>
> Cc: intel-gfx at lists.freedesktop.org; dri-devel at lists.freedesktop.org; Modem,
> Bhanuprakash <bhanuprakash.modem at intel.com>
> Subject: Re: [PATCH 01/21] drm: Add Enhanced Gamma and color lut range
> attributes
> 
> 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.

Ok, will rename these.

> > +	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?

The concept and idea is similar and the range definition is also common. But this series
focuses on plane color management while the other one is for pipe/crtc color features.
Hence separated and floated them as unique series for review.

Regards,
Uma Shankar
> 
> 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