On Fri, Jan 10, 2025 at 01:15:30AM +0530, Arun R Murthy wrote:
> ImageEnhancemenT(IET) hardware interpolates the LUT value to generate
> the enhanced output image. LUT takes an input value, outputs a new
> value based on the data within the LUT. 1D LUT can remap individual
> input values to new output values based on the LUT sample. LUT can be
> interpolated by the hardware by multiple modes Ex: Direct Lookup LUT,
> Multiplicative LUT etc
> The list of supported mode by hardware along with the format(exponent
> mantissa) is exposed to user by the iet_lut_caps property. Maximum
> format being 8.24 i.e 8 exponent and 24 mantissa.
> For illustration a hardware supporting 1.9 format denotes this as
> 0x10001FF. In order to know the exponent do a bitwise AND with
> 0xF000000. The LUT value to be provided by user would be a 10bit value
> with 1 bit integer and 9 bit fractional value.
>
> Multiple formats can be supported, hence pointer is used over here.
> User can then provide the LUT with any one of the supported modes in
> any of the supported formats.
> The entries in the LUT can vary depending on the hardware capability
> with max being 255. This will also be exposed as iet_lut_caps so user
> can generate a LUT with the specified entries.
>
> Signed-off-by: Arun R Murthy <arun.r.murthy@xxxxxxxxx>
> ---
> include/uapi/drm/drm_mode.h | 50 +++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 50 insertions(+)
>
> diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
> index 7a7039381142bb5dba269bdaec42c18be34e2d05..056c2efef1589848034afc0089f1838c2547bcf8 100644
> --- a/include/uapi/drm/drm_mode.h
> +++ b/include/uapi/drm/drm_mode.h
> @@ -1367,6 +1367,17 @@ struct drm_mode_closefb {
> */
> #define DRM_MODE_HISTOGRAM_HSV_MAX_RGB (1 << 0)
>
> +/* LUT values are points on exponential graph with x axis and y-axis y=f(x) */
Huh?
> +#define DRM_MODE_IET_LOOKUP_LUT (1 << 0)
Again, what is the reason for a shift? Can these values be OR'd?
> +/*
> + * LUT values, points on negative exponential graph with x-axis and y-axis
> + * y = y/x so upon multiplying x, y is obtained, hence multiplicative. The
Can't parse this sentence.
> + * format of LUT can at max be 8.24(8integer 24 fractional) represented by
> + * u32. Depending on the hardware capability and exponent mantissa can be
> + * chosen.
What does that mean? How is it choosen?
> + */
> +#define DRM_MODE_IET_MULTIPLICATIVE (1 << 1)
> +
> /**
> * struct drm_histogram_caps
> *
> @@ -1414,6 +1425,45 @@ struct drm_histogram {
> __u32 nr_elements;
> };
>
> +/**
> + * struct drm_iet_caps
> + *
> + * @iet_mode: pixel factor enhancement modes defined in the above macros
> + * @iet_sample_format: holds the address of an array of u32 LUT sample formats
> + * depending on the hardware capability. Max being 8.24
> + * Doing a bitwise AND will get the present sample.
> + * Ex: for 1 integer 9 fraction AND with 0x10001FF
?? Can hardware support 16.16? 32.0?
> + * @nr_iet_sample_formats: number of iet_sample_formsts supported by the
> + * hardware
> + * @nr_iet_lut_entries: number of LUT entries
> + */
> +struct drm_iet_caps {
> + __u8 iet_mode;
> + u64 iet_sample_format;
> + __u32 nr_iet_sample_formats;
> + __u32 nr_iet_lut_entries;
> +};
> +
> +/**
> + * struct drm_iet_1dlut_sample
Is it supposed to be used with DRM_MODE_IET_MULTIPLICATIVE only? Or is
it supposed to be used with DRM_MODE_IET_LOOKUP_LUT? In the latter case
what should be the iet_format value?
> + * @iet_mode: image enhancement mode, this will also convey the channel.
> + * @iet_format: LUT exponent and mantissa format, max being 8.24
> + * @data_ptr: pointer to the array of values which is of type u32.
> + * 1 channel: 10 bit corrected value and remaining bits are reserved.
> + * multi channel: pointer to struct drm_color_lut
> + * @nr_elements: number of entries pointed by the data @data_ptr
> + * @reserved: reserved for future use
> + * @reserved1: reserved for future use
> + */
> +struct drm_iet_1dlut_sample {
> + __u8 iet_mode;
> + __u32 iet_format;
> + __u64 data_ptr;
> + __u32 nr_elements;
> + __u32 reserved;
> + __u32 reserved1;
> +};
> +
> #if defined(__cplusplus)
> }
> #endif
>
> --
> 2.25.1
>
--
With best wishes
Dmitry
