Re: [PATCH v5 11/16] drm/vkms: Add YUV support

[Philipp Zabel <p.zabel@pengutronix.de>]

Hi Louis,

On Mi, 2024-03-13 at 18:45 +0100, Louis Chauvet wrote:
> From: Arthur Grillo <arthurgrillo@riseup.net>
> 
> Add support to the YUV formats bellow:
> 
> - NV12/NV16/NV24
> - NV21/NV61/NV42
> - YUV420/YUV422/YUV444
> - YVU420/YVU422/YVU444
> 
> The conversion from yuv to rgb is done with fixed-point arithmetic, using
> 32.32 floats and the drm_fixed helpers.

s/floats/fixed-point numbers/

Nothing floating here, the point is fixed.

[...]
> diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
> index 23e1d247468d..f3116084de5a 100644
> --- a/drivers/gpu/drm/vkms/vkms_drv.h
> +++ b/drivers/gpu/drm/vkms/vkms_drv.h
> @@ -99,6 +99,27 @@ typedef void (*pixel_read_line_t)(const struct vkms_plane_state *plane, int x_st
>  				  int y_start, enum pixel_read_direction direction, int count,
>  				  struct pixel_argb_u16 out_pixel[]);
>  
> +/**
> + * CONVERSION_MATRIX_FLOAT_DEPTH - Number of digits after the point for conversion matrix values

s/CONVERSION_MATRIX_FLOAT_DEPTH/CONVERSION_MATRIX_FRACTIONAL_BITS/

Just a suggestion, maybe there are better terms, but using "FLOAT" here
is confusing.

> + */
> +#define CONVERSION_MATRIX_FLOAT_DEPTH 32
> +
> +/**
> + * struct conversion_matrix - Matrix to use for a specific encoding and range
> + *
> + * @matrix: Conversion matrix from yuv to rgb. The matrix is stored in a row-major manner and is
> + * used to compute rgb values from yuv values:
> + *     [[r],[g],[b]] = @matrix * [[y],[u],[v]]
> + *   OR for yvu formats:
> + *     [[r],[g],[b]] = @matrix * [[y],[v],[u]]
> + *  The values of the matrix are fixed floats, 32.CONVERSION_MATRIX_FLOAT_DEPTH

s/fixed floats/fixed-point numbers/

regards
Philipp