Re: [PATCH v13 11/27] drm/i915/hdmi: Add YCBCR444 handling for sink formats

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Mon, Apr 13, 2026 at 12:07:25PM +0200, Nicolas Frattaroli wrote:
> In anticipation of userspace being able to explicitly select supported
> sink formats, add handling of the YCBCR444 sink format. The AUTO path
> does not choose this format, but with explicit format selection added to
> the driver, it becomes a possibility.
> 
> Check for YCBCR444 support on the sink in both sink_bpc_possible, and
> sink_format_valid.
> 
> Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
> ---
>  drivers/gpu/drm/i915/display/intel_hdmi.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
> index 874076a29da4..5ab5b5f85cde 100644
> --- a/drivers/gpu/drm/i915/display/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
> @@ -1966,6 +1966,8 @@ static bool intel_hdmi_sink_bpc_possible(struct drm_connector *_connector,
>  
>  		if (sink_format == INTEL_OUTPUT_FORMAT_YCBCR420)
>  			return hdmi->y420_dc_modes & DRM_EDID_YCBCR420_DC_36;
> +		else if (sink_format == INTEL_OUTPUT_FORMAT_YCBCR444)
> +			return info->edid_hdmi_ycbcr444_dc_modes & DRM_EDID_HDMI_DC_36;
>  		else
>  			return info->edid_hdmi_rgb444_dc_modes & DRM_EDID_HDMI_DC_36;
>  	case 10:
> @@ -1974,6 +1976,8 @@ static bool intel_hdmi_sink_bpc_possible(struct drm_connector *_connector,
>  
>  		if (sink_format == INTEL_OUTPUT_FORMAT_YCBCR420)
>  			return hdmi->y420_dc_modes & DRM_EDID_YCBCR420_DC_30;
> +		else if (sink_format == INTEL_OUTPUT_FORMAT_YCBCR444)
> +			return info->edid_hdmi_ycbcr444_dc_modes & DRM_EDID_HDMI_DC_30;
>  		else
>  			return info->edid_hdmi_rgb444_dc_modes & DRM_EDID_HDMI_DC_30;
>  	case 8:
> @@ -2038,6 +2042,11 @@ intel_hdmi_sink_format_valid(struct intel_connector *connector,
>  
>  		return MODE_OK;
>  	case INTEL_OUTPUT_FORMAT_RGB:
> +		return MODE_OK;
> +	case INTEL_OUTPUT_FORMAT_YCBCR444:

We'll also want the !has_hdmi_sink check here like for 4:2:0.

And I think we also want something to mirror the ycbcr_420_allowed
flag. I guess you could just make it something like:

intel_hdmi_ycbcr_444_allowed(display)
{
	return DISPLAY_VER(display) >= 5 && !HAS_GMCH(display);
}

That can also be reused when setting up the allowed property values.

> +		if (!(info->color_formats & BIT(DRM_OUTPUT_COLOR_FORMAT_YCBCR444)))
> +			return MODE_BAD;
> +
>  		return MODE_OK;
>  	default:
>  		MISSING_CASE(sink_format);
> 
> -- 
> 2.53.0

-- 
Ville Syrjälä
Intel