Re: [Intel-gfx] [PATCH 19/29] drm/i915/dp: Disable FEC ready flag in the sink

["Lisovskiy, Stanislav" <stanislav.lisovskiy@intel.com>]

On Tue, Oct 24, 2023 at 04:09:15AM +0300, Imre Deak wrote:
> Disable the FEC ready flag in the sink during a disabling modeset.
> 
> Signed-off-by: Imre Deak <imre.deak@intel.com>

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

> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c | 21 +++++++++++++--------
>  1 file changed, 13 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 6f9d0f2ff3d9a..99d96762fa29c 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -2211,18 +2211,21 @@ static void intel_dp_sink_set_msa_timing_par_ignore_state(struct intel_dp *intel
>  }
>  
>  static void intel_dp_sink_set_fec_ready(struct intel_dp *intel_dp,
> -					const struct intel_crtc_state *crtc_state)
> +					const struct intel_crtc_state *crtc_state,
> +					bool enable)
>  {
>  	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
>  
>  	if (!crtc_state->fec_enable)
>  		return;
>  
> -	if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_FEC_CONFIGURATION, DP_FEC_READY) <= 0)
> -		drm_dbg_kms(&i915->drm,
> -			    "Failed to set FEC_READY in the sink\n");
> +	if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_FEC_CONFIGURATION,
> +			       enable ? DP_FEC_READY : 0) <= 0)
> +		drm_dbg_kms(&i915->drm, "Failed to set FEC_READY to %s in the sink\n",
> +			    enable ? "enabled" : "disabled");
>  
> -	if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_FEC_STATUS,
> +	if (enable &&
> +	    drm_dp_dpcd_writeb(&intel_dp->aux, DP_FEC_STATUS,
>  			       DP_FEC_DECODE_EN_DETECTED | DP_FEC_DECODE_DIS_DETECTED) <= 0)
>  		drm_dbg_kms(&i915->drm, "Failed to clear FEC detected flags\n");
>  }
> @@ -2541,7 +2544,7 @@ static void mtl_ddi_pre_enable_dp(struct intel_atomic_state *state,
>  	 * in the FEC_CONFIGURATION register to 1 before initiating link
>  	 * training
>  	 */
> -	intel_dp_sink_set_fec_ready(intel_dp, crtc_state);
> +	intel_dp_sink_set_fec_ready(intel_dp, crtc_state, true);
>  
>  	intel_dp_check_frl_training(intel_dp);
>  	intel_dp_pcon_dsc_configure(intel_dp, crtc_state);
> @@ -2692,7 +2695,7 @@ static void tgl_ddi_pre_enable_dp(struct intel_atomic_state *state,
>  	 * in the FEC_CONFIGURATION register to 1 before initiating link
>  	 * training
>  	 */
> -	intel_dp_sink_set_fec_ready(intel_dp, crtc_state);
> +	intel_dp_sink_set_fec_ready(intel_dp, crtc_state, true);
>  
>  	intel_dp_check_frl_training(intel_dp);
>  	intel_dp_pcon_dsc_configure(intel_dp, crtc_state);
> @@ -2768,7 +2771,7 @@ static void hsw_ddi_pre_enable_dp(struct intel_atomic_state *state,
>  	intel_dp_configure_protocol_converter(intel_dp, crtc_state);
>  	intel_dp_sink_set_decompression_state(intel_dp, crtc_state,
>  					      true);
> -	intel_dp_sink_set_fec_ready(intel_dp, crtc_state);
> +	intel_dp_sink_set_fec_ready(intel_dp, crtc_state, true);
>  	intel_dp_start_link_train(intel_dp, crtc_state);
>  	if ((port != PORT_A || DISPLAY_VER(dev_priv) >= 9) &&
>  	    !is_trans_port_sync_mode(crtc_state))
> @@ -2997,6 +3000,8 @@ static void intel_ddi_post_disable_dp(struct intel_atomic_state *state,
>  
>  	intel_disable_ddi_buf(encoder, old_crtc_state);
>  
> +	intel_dp_sink_set_fec_ready(intel_dp, old_crtc_state, false);
> +
>  	/*
>  	 * From TGL spec: "If single stream or multi-stream master transcoder:
>  	 * Configure Transcoder Clock select to direct no clock to the
> -- 
> 2.39.2
>