Re: [Intel-gfx] [PATCH v9 2/7] drm/i915/dp: Check if DSC supports the given output_format

["Shankar, Uma" <uma.shankar@intel.com>]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of Suraj
> Kandpal
> Sent: Tuesday, February 7, 2023 1:14 PM
> To: intel-gfx@lists.freedesktop.org
> Subject: [Intel-gfx] [PATCH v9 2/7] drm/i915/dp: Check if DSC supports the given
> output_format
> 
> From: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> 
> Go with DSC only if the given output_format is supported.
> 
> v2: Use drm helper to get DSC format support for sink.
> 
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 30 +++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index cb4fbcd935db..73a7baccd7d0 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -1494,6 +1494,31 @@ static int intel_dp_dsc_compute_params(struct
> intel_encoder *encoder,
>  	return drm_dsc_compute_rc_parameters(vdsc_cfg);
>  }
> 
> +static bool intel_dp_dsc_supports_format(struct intel_dp *intel_dp,
> +					 enum intel_output_format output_format)
> {
> +	u8 sink_dsc_format;
> +
> +	switch (output_format) {
> +	case INTEL_OUTPUT_FORMAT_RGB:
> +		sink_dsc_format = DP_DSC_RGB;
> +		break;
> +	case INTEL_OUTPUT_FORMAT_YCBCR444:
> +		sink_dsc_format = DP_DSC_YCbCr444;
> +		break;
> +	case INTEL_OUTPUT_FORMAT_YCBCR420:
> +		if (min(intel_dp_source_dsc_version_minor(intel_dp),
> +			intel_dp_sink_dsc_version_minor(intel_dp)) < 2)
> +			return false;
> +		sink_dsc_format = DP_DSC_YCbCr420_Native;
> +		break;
> +	default:
> +		return false;
> +	}
> +
> +	return drm_dp_dsc_sink_supports_format(intel_dp->dsc_dpcd,
> +sink_dsc_format); }
> +
>  int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
>  				struct intel_crtc_state *pipe_config,
>  				struct drm_connector_state *conn_state, @@ -
> 1514,11 +1539,16 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
>  	if (!intel_dp_supports_dsc(intel_dp, pipe_config))
>  		return -EINVAL;
> 
> +	if (!intel_dp_dsc_supports_format(intel_dp, pipe_config->output_format))
> +		return -EINVAL;
> +
>  	if (compute_pipe_bpp)
>  		pipe_bpp = intel_dp_dsc_compute_bpp(intel_dp, conn_state-
> >max_requested_bpc);
>  	else
>  		pipe_bpp = pipe_config->pipe_bpp;
> 
> +	pipe_bpp = intel_dp_dsc_compute_bpp(intel_dp,
> +conn_state->max_requested_bpc);

This seems to be  wrong as it unconditionally overwrites the non-compress case.

> +
>  	if (intel_dp->force_dsc_bpc) {
>  		pipe_bpp = intel_dp->force_dsc_bpc * 3;
>  		drm_dbg_kms(&dev_priv->drm, "Input DSC BPP forced to %d",
> pipe_bpp);
> --
> 2.25.1