[Intel-gfx] [v7 3/3] drm/i915/display/dsc: Force dsc BPP

[Jani Nikula]

On Thu, 08 Jul 2021, Vandita Kulkarni <vandita.kulkarni at intel.com> wrote:
> Set DSC BPP to the value forced through
> debugfs. It can go from bpc to bpp-1.
>
> Signed-off-by: Vandita Kulkarni <vandita.kulkarni at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 5b52beaddada..3e50cdd7e448 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -1240,6 +1240,23 @@ static int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
>  	pipe_config->port_clock = intel_dp->common_rates[limits->max_clock];
>  	pipe_config->lane_count = limits->max_lane_count;
>  
> +	if (intel_dp->force_dsc_en) {
> +		/* As of today we support DSC for only RGB */
> +		if (intel_dp->force_dsc_bpp >= 8 &&
> +		    intel_dp->force_dsc_bpp < pipe_bpp) {
> +			drm_dbg_kms(&dev_priv->drm,
> +				    "DSC BPP forced to %d",
> +				    intel_dp->force_dsc_bpp);
> +			pipe_config->dsc.compressed_bpp =
> +						intel_dp->force_dsc_bpp;
> +		} else {
> +			drm_dbg_kms(&dev_priv->drm,
> +				    "Invalid DSC BPP %d",
> +				    intel_dp->force_dsc_bpp);
> +			return -EINVAL;

I'd just let it use the normal compressed_bpp, with the debug message,
instead of returning -EINVAL.

> +		}
> +	}
> +

This should be *after* the below blocks, because otherwise
compressed_bpp will be overridden by the normal case, not by the force
case!

BR,
Jani.

>  	if (intel_dp_is_edp(intel_dp)) {
>  		pipe_config->dsc.compressed_bpp =
>  			min_t(u16, drm_edp_dsc_sink_output_bpp(intel_dp->dsc_dpcd) >> 4,

-- 
Jani Nikula, Intel Open Source Graphics Center