[Intel-gfx] [PATCH v2 01/22] drm/i915/dp: Factor out helpers to compute the link limits

Ville Syrjälä ville.syrjala at linux.intel.com
Mon Sep 4 03:19:04 UTC 2023


On Thu, Aug 24, 2023 at 11:04:56AM +0300, Imre Deak wrote:
> Factor out helpers that DP / DP_MST encoders can use to compute the link
> rate/lane count and bpp limits. A follow-up patch will call these to
> recalculate the limits if DSC compression is required.
> 
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c     | 61 +++++++++++++--------
>  drivers/gpu/drm/i915/display/intel_dp_mst.c | 52 ++++++++++--------
>  2 files changed, 68 insertions(+), 45 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 7067ee3a4bd36..53697f361f950 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -2187,29 +2187,25 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
>  	return 0;
>  }
>  
> -static int
> -intel_dp_compute_link_config(struct intel_encoder *encoder,
> -			     struct intel_crtc_state *pipe_config,
> -			     struct drm_connector_state *conn_state,
> -			     bool respect_downstream_limits)
> +static void
> +intel_dp_compute_config_limits(struct intel_dp *intel_dp,
> +			       struct intel_crtc_state *crtc_state,
> +			       bool respect_downstream_limits,
> +			       struct link_config_limits *limits)
>  {
> -	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> -	struct intel_crtc *crtc = to_intel_crtc(pipe_config->uapi.crtc);
> +	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
>  	const struct drm_display_mode *adjusted_mode =
> -		&pipe_config->hw.adjusted_mode;
> -	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> -	struct link_config_limits limits;
> -	bool joiner_needs_dsc = false;
> -	int ret;
> +		&crtc_state->hw.adjusted_mode;
>  
> -	limits.min_rate = intel_dp_common_rate(intel_dp, 0);
> -	limits.max_rate = intel_dp_max_link_rate(intel_dp);
> +	limits->min_rate = intel_dp_common_rate(intel_dp, 0);
> +	limits->max_rate = intel_dp_max_link_rate(intel_dp);
>  
> -	limits.min_lane_count = 1;
> -	limits.max_lane_count = intel_dp_max_lane_count(intel_dp);
> +	limits->min_lane_count = 1;
> +	limits->max_lane_count = intel_dp_max_lane_count(intel_dp);
>  
> -	limits.min_bpp = intel_dp_min_bpp(pipe_config->output_format);
> -	limits.max_bpp = intel_dp_max_bpp(intel_dp, pipe_config, respect_downstream_limits);
> +	limits->min_bpp = intel_dp_min_bpp(crtc_state->output_format);
> +	limits->max_bpp = intel_dp_max_bpp(intel_dp, crtc_state,
> +					   respect_downstream_limits);
>  
>  	if (intel_dp->use_max_params) {
>  		/*
> @@ -2220,16 +2216,35 @@ intel_dp_compute_link_config(struct intel_encoder *encoder,
>  		 * configuration, and typically on older panels these
>  		 * values correspond to the native resolution of the panel.
>  		 */
> -		limits.min_lane_count = limits.max_lane_count;
> -		limits.min_rate = limits.max_rate;
> +		limits->min_lane_count = limits->max_lane_count;
> +		limits->min_rate = limits->max_rate;
>  	}
>  
> -	intel_dp_adjust_compliance_config(intel_dp, pipe_config, &limits);
> +	intel_dp_adjust_compliance_config(intel_dp, crtc_state, limits);

Annoying little bugger that mutates the crtc_state. Would be nice
to relocate that small part somewhere else so that we could constify
things more...

Anyways
Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

>  
>  	drm_dbg_kms(&i915->drm, "DP link computation with max lane count %i "
>  		    "max rate %d max bpp %d pixel clock %iKHz\n",
> -		    limits.max_lane_count, limits.max_rate,
> -		    limits.max_bpp, adjusted_mode->crtc_clock);
> +		    limits->max_lane_count, limits->max_rate,
> +		    limits->max_bpp, adjusted_mode->crtc_clock);
> +}
> +
> +static int
> +intel_dp_compute_link_config(struct intel_encoder *encoder,
> +			     struct intel_crtc_state *pipe_config,
> +			     struct drm_connector_state *conn_state,
> +			     bool respect_downstream_limits)
> +{
> +	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> +	struct intel_crtc *crtc = to_intel_crtc(pipe_config->uapi.crtc);
> +	const struct drm_display_mode *adjusted_mode =
> +		&pipe_config->hw.adjusted_mode;
> +	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> +	struct link_config_limits limits;
> +	bool joiner_needs_dsc = false;
> +	int ret;
> +
> +	intel_dp_compute_config_limits(intel_dp, pipe_config,
> +				       respect_downstream_limits, &limits);
>  
>  	if (intel_dp_need_bigjoiner(intel_dp, adjusted_mode->crtc_hdisplay,
>  				    adjusted_mode->crtc_clock))
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index 3eb085fbc7c82..218c2dfd57adc 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -306,6 +306,35 @@ static bool intel_dp_mst_has_audio(const struct drm_connector_state *conn_state)
>  		return intel_conn_state->force_audio == HDMI_AUDIO_ON;
>  }
>  
> +static void
> +intel_dp_mst_compute_config_limits(struct intel_dp *intel_dp,
> +				   struct intel_crtc_state *crtc_state,
> +				   struct link_config_limits *limits)
> +{
> +	/*
> +	 * for MST we always configure max link bw - the spec doesn't
> +	 * seem to suggest we should do otherwise.
> +	 */
> +	limits->min_rate = limits->max_rate =
> +		intel_dp_max_link_rate(intel_dp);
> +
> +	limits->min_lane_count = limits->max_lane_count =
> +		intel_dp_max_lane_count(intel_dp);
> +
> +	limits->min_bpp = intel_dp_min_bpp(crtc_state->output_format);
> +	/*
> +	 * FIXME: If all the streams can't fit into the link with
> +	 * their current pipe_bpp we should reduce pipe_bpp across
> +	 * the board until things start to fit. Until then we
> +	 * limit to <= 8bpc since that's what was hardcoded for all
> +	 * MST streams previously. This hack should be removed once
> +	 * we have the proper retry logic in place.
> +	 */
> +	limits->max_bpp = min(crtc_state->pipe_bpp, 24);
> +
> +	intel_dp_adjust_compliance_config(intel_dp, crtc_state, limits);
> +}
> +
>  static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
>  				       struct intel_crtc_state *pipe_config,
>  				       struct drm_connector_state *conn_state)
> @@ -329,28 +358,7 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
>  		intel_dp_mst_has_audio(conn_state) &&
>  		intel_audio_compute_config(encoder, pipe_config, conn_state);
>  
> -	/*
> -	 * for MST we always configure max link bw - the spec doesn't
> -	 * seem to suggest we should do otherwise.
> -	 */
> -	limits.min_rate =
> -	limits.max_rate = intel_dp_max_link_rate(intel_dp);
> -
> -	limits.min_lane_count =
> -	limits.max_lane_count = intel_dp_max_lane_count(intel_dp);
> -
> -	limits.min_bpp = intel_dp_min_bpp(pipe_config->output_format);
> -	/*
> -	 * FIXME: If all the streams can't fit into the link with
> -	 * their current pipe_bpp we should reduce pipe_bpp across
> -	 * the board until things start to fit. Until then we
> -	 * limit to <= 8bpc since that's what was hardcoded for all
> -	 * MST streams previously. This hack should be removed once
> -	 * we have the proper retry logic in place.
> -	 */
> -	limits.max_bpp = min(pipe_config->pipe_bpp, 24);
> -
> -	intel_dp_adjust_compliance_config(intel_dp, pipe_config, &limits);
> +	intel_dp_mst_compute_config_limits(intel_dp, pipe_config, &limits);
>  
>  	ret = intel_dp_mst_compute_link_config(encoder, pipe_config,
>  					       conn_state, &limits);
> -- 
> 2.37.2

-- 
Ville Syrjälä
Intel


More information about the Intel-gfx mailing list