Re: [PATCH v4 09/11] drm: xlnx: zynqmp: Add support for Y8 and Y10_P32

[Laurent Pinchart]

Hi Tomi,

Thank you for the patch.

On Wed, Mar 26, 2025 at 03:22:52PM +0200, Tomi Valkeinen wrote:
> Add support for Y8 and Y10_P32 formats. We also need to add new csc
> matrices for the y-only formats.
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/xlnx/zynqmp_disp.c | 26 +++++++++++++++++++++++++-
>  1 file changed, 25 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xlnx/zynqmp_disp.c b/drivers/gpu/drm/xlnx/zynqmp_disp.c
> index 1dc77f2e4262..ae8b4073edf6 100644
> --- a/drivers/gpu/drm/xlnx/zynqmp_disp.c
> +++ b/drivers/gpu/drm/xlnx/zynqmp_disp.c
> @@ -307,6 +307,16 @@ static const struct zynqmp_disp_format avbuf_vid_fmts[] = {
>  		.buf_fmt	= ZYNQMP_DISP_AV_BUF_FMT_NL_VID_YV16CI_10,
>  		.swap		= false,
>  		.sf		= scaling_factors_101010,
> +	}, {
> +		.drm_fmt	= DRM_FORMAT_Y8,
> +		.buf_fmt	= ZYNQMP_DISP_AV_BUF_FMT_NL_VID_MONO,
> +		.swap		= false,
> +		.sf		= scaling_factors_888,
> +	}, {
> +		.drm_fmt	= DRM_FORMAT_Y10_P32,
> +		.buf_fmt	= ZYNQMP_DISP_AV_BUF_FMT_NL_VID_YONLY_10,
> +		.swap		= false,
> +		.sf		= scaling_factors_101010,

Assuming the DRM format definitions get approved, this looks good to me.

>  	},
>  };
>  
> @@ -697,6 +707,16 @@ static const u32 csc_sdtv_to_rgb_offsets[] = {
>  	0x0, 0x1800, 0x1800
>  };
>  
> +static const u16 csc_sdtv_to_rgb_yonly_matrix[] = {

TODO: Add support for colorspaces to the driver.

> +	0x0, 0x0, 0x1000,
> +	0x0, 0x0, 0x1000,
> +	0x0, 0x0, 0x1000,

This surprises me a bit, I was expecting 0x1000 to be in the first
column. What am I missing ?

> +};
> +
> +static const u32 csc_sdtv_to_rgb_yonly_offsets[] = {
> +	0x1800, 0x1800, 0x0

Why do you need offsets ? Those values correspond to -128 in a 8-bit
range, and that's what would need to be applied to the chroma values.
There's no chroma here. I think you could use csc_zero_offsets.

> +};
> +
>  /**
>   * zynqmp_disp_blend_set_output_format - Set the output format of the blender
>   * @disp: Display controller
> @@ -846,7 +866,11 @@ static void zynqmp_disp_blend_layer_enable(struct zynqmp_disp *disp,
>  				ZYNQMP_DISP_V_BLEND_LAYER_CONTROL(layer->id),
>  				val);
>  
> -	if (layer->drm_fmt->is_yuv) {
> +	if (layer->drm_fmt->format == DRM_FORMAT_Y8 ||
> +	    layer->drm_fmt->format == DRM_FORMAT_Y10_P32) {
> +		coeffs = csc_sdtv_to_rgb_yonly_matrix;
> +		offsets = csc_sdtv_to_rgb_yonly_offsets;
> +	} else if (layer->drm_fmt->is_yuv) {
>  		coeffs = csc_sdtv_to_rgb_matrix;
>  		offsets = csc_sdtv_to_rgb_offsets;
>  	} else {

-- 
Regards,

Laurent Pinchart