[Intel-gfx] [PATCH v2 18/22] drm/i915/dp_mst: Enable DSC decompression if any stream needs this

[Lisovskiy, Stanislav]

On Thu, Aug 24, 2023 at 11:05:13AM +0300, Imre Deak wrote:
> Atm DSC decompression is enabled in the sink only if the first stream is
> compressed. This left compressed streams blank if the first stream was
> uncompressed.
> 
> Enable decompression whenever FEC is enabled, which will be true for all
> streams if any stream is compressed. Enabling FEC correctly in all
> streams will be only fixed by an upcoming patch.
> 
> Signed-off-by: Imre Deak <imre.deak at intel.com>

Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 48f005932ad8b..e5b1567d2a9d4 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -2907,7 +2907,13 @@ void intel_dp_sink_set_decompression_state(struct intel_dp *intel_dp,
>  	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
>  	int ret;
>  
> -	if (!crtc_state->dsc.compression_enable)
> +	/*
> +	 * In case of MST any stream can be compressed not just the first. If
> +	 * any stream is compressed FEC will be enabled in all streams, so toggle
> +	 * decompression whenever FEC is enabled.
> +	 */
> +	if (!crtc_state->dsc.compression_enable &&
> +	    !crtc_state->fec_enable)
>  		return;
>  
>  	ret = drm_dp_dpcd_writeb(&intel_dp->aux, DP_DSC_ENABLE,
> -- 
> 2.37.2
>