[RFC v3 14/15] drm/i915/ddi: handle 128b/132b SST in intel_ddi_read_func_ctl()

[Jani Nikula]

On Wed, 18 Dec 2024, Imre Deak <imre.deak at intel.com> wrote:
> From: Jani Nikula <jani.nikula at intel.com>
>
> We'll only ever get here in MST mode from MST stream encoders; the
> primary encoder's ->get_config() won't be called when we've detected
> it's MST.
>
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
> [hack: fix enhanced framing hw readout/set master transcoder] (Imre)
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c      | 34 ++++++++++++++++---
>  drivers/gpu/drm/i915/display/intel_dp.c       |  8 +++--
>  .../drm/i915/display/intel_dp_link_training.c |  5 ++-
>  3 files changed, 39 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 21dba87350856..14d8eb5f02ff1 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -577,10 +577,18 @@ intel_ddi_transcoder_func_reg_val_get(struct intel_encoder *encoder,
>  			temp |= TRANS_DDI_MST_TRANSPORT_SELECT(master);
>  		}
>  	} else {
> -		if (intel_dp_is_uhbr(crtc_state))
> +		if (intel_dp_is_uhbr(crtc_state)) {
> +			enum transcoder master;
> +
>  			temp |= TRANS_DDI_MODE_SELECT_FDI_OR_128B132B;
> -		else
> +
> +			master = crtc_state->mst_master_transcoder;
> +			drm_WARN_ON(&dev_priv->drm,
> +				    master == INVALID_TRANSCODER);
> +			temp |= TRANS_DDI_MST_TRANSPORT_SELECT(master);
> +		} else {
>  			temp |= TRANS_DDI_MODE_SELECT_DP_SST;
> +		}
>  		temp |= DDI_PORT_WIDTH(crtc_state->lane_count);
>  	}
>  
> @@ -678,7 +686,8 @@ void intel_ddi_disable_transcoder_func(const struct intel_crtc_state *crtc_state
>  			 TRANS_DDI_PORT_SYNC_MASTER_SELECT_MASK);
>  
>  	if (DISPLAY_VER(dev_priv) >= 12) {
> -		if (!intel_dp_mst_is_master_trans(crtc_state)) {
> +		if (!intel_dp_mst_is_master_trans(crtc_state) ||
> +		    intel_dp_is_uhbr(crtc_state)) {

Hmm, what if this gets called from UHBR MST where this would also
disable master transcoder?

I'll switch this to:

	bool is_mst = intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP_MST);

        ...

		if (!intel_dp_mst_is_master_trans(crtc_state) ||
		    (!is_mst && intel_dp_is_uhbr(crtc_state)) {

BR,
Jani.



>  			ctl &= ~(TGL_TRANS_DDI_PORT_MASK |
>  				 TRANS_DDI_MODE_SELECT_MASK);
>  		}
> @@ -4028,6 +4037,11 @@ static void intel_ddi_read_func_ctl_dp_sst(struct intel_encoder *encoder,
>  	crtc_state->lane_count =
>  		((ddi_func_ctl & DDI_PORT_WIDTH_MASK) >> DDI_PORT_WIDTH_SHIFT) + 1;
>  
> +	if (DISPLAY_VER(display) >= 12 &&
> +	    (ddi_func_ctl & TRANS_DDI_MODE_SELECT_MASK) == TRANS_DDI_MODE_SELECT_FDI_OR_128B132B)
> +		crtc_state->mst_master_transcoder =
> +			REG_FIELD_GET(TRANS_DDI_MST_TRANSPORT_SELECT_MASK, ddi_func_ctl);
> +
>  	intel_cpu_transcoder_get_m1_n1(crtc, cpu_transcoder, &crtc_state->dp_m_n);
>  	intel_cpu_transcoder_get_m2_n2(crtc, cpu_transcoder, &crtc_state->dp_m2_n2);
>  
> @@ -4122,9 +4136,19 @@ static void intel_ddi_read_func_ctl(struct intel_encoder *encoder,
>  		intel_ddi_read_func_ctl_fdi(encoder, pipe_config, ddi_func_ctl);
>  	} else if (ddi_mode == TRANS_DDI_MODE_SELECT_DP_SST) {
>  		intel_ddi_read_func_ctl_dp_sst(encoder, pipe_config, ddi_func_ctl);
> -	} else if (ddi_mode == TRANS_DDI_MODE_SELECT_DP_MST ||
> -		   (ddi_mode == TRANS_DDI_MODE_SELECT_FDI_OR_128B132B && HAS_DP20(display))) {
> +	} else if (ddi_mode == TRANS_DDI_MODE_SELECT_DP_MST) {
>  		intel_ddi_read_func_ctl_dp_mst(encoder, pipe_config, ddi_func_ctl);
> +	} else if (ddi_mode == TRANS_DDI_MODE_SELECT_FDI_OR_128B132B && HAS_DP20(display)) {
> +		struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> +
> +		/*
> +		 * If this is true, we know we're being called from mst stream
> +		 * encoder's ->get_config().
> +		 */
> +		if (intel_dp->is_mst)
> +			intel_ddi_read_func_ctl_dp_mst(encoder, pipe_config, ddi_func_ctl);
> +		else
> +			intel_ddi_read_func_ctl_dp_sst(encoder, pipe_config, ddi_func_ctl);
>  	}
>  }
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index fba3af3382808..dc84979d32947 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -3148,8 +3148,12 @@ intel_dp_compute_config(struct intel_encoder *encoder,
>  	pipe_config->limited_color_range =
>  		intel_dp_limited_color_range(pipe_config, conn_state);
>  
> -	pipe_config->enhanced_framing =
> -		drm_dp_enhanced_frame_cap(intel_dp->dpcd);
> +	if (intel_dp_is_uhbr(pipe_config)) {
> +		pipe_config->mst_master_transcoder = pipe_config->cpu_transcoder;
> +	} else {
> +		pipe_config->enhanced_framing =
> +			drm_dp_enhanced_frame_cap(intel_dp->dpcd);
> +	}
>  
>  	if (pipe_config->dsc.compression_enable)
>  		link_bpp_x16 = pipe_config->dsc.compressed_bpp_x16;
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> index 8b1977cfec503..7304220736b47 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> @@ -760,8 +760,11 @@ static void intel_dp_update_link_bw_set(struct intel_dp *intel_dp,
>  					const struct intel_crtc_state *crtc_state,
>  					u8 link_bw, u8 rate_select)
>  {
> +	bool enhanced_framing = crtc_state->enhanced_framing ||
> +				intel_dp_is_uhbr(crtc_state);
> +
>  	intel_dp_link_training_set_bw(intel_dp, link_bw, rate_select, crtc_state->lane_count,
> -				      crtc_state->enhanced_framing);
> +				      enhanced_framing);
>  }
>  
>  /*

-- 
Jani Nikula, Intel