[PATCH 09/19] drm/i915/dp: Add intel_dp_max_link_data_rate()

[Shankar, Uma]

> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of Imre
> Deak
> Sent: Tuesday, January 23, 2024 3:59 PM
> To: intel-gfx at lists.freedesktop.org
> Cc: dri-devel at lists.freedesktop.org
> Subject: [PATCH 09/19] drm/i915/dp: Add intel_dp_max_link_data_rate()
> 
> Add intel_dp_max_link_data_rate() to get the link BW vs. the sink DPRX BW used
> by a follow-up patch enabling the DP tunnel BW allocation mode.
> The link BW can be below the DPRX BW due to a BW limitation on a link shared
> by multiple sinks.

Looks good to me.
Reviewed-by: Uma Shankar <uma.shankar at intel.com>

> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c     | 32 +++++++++++++++++----
>  drivers/gpu/drm/i915/display/intel_dp.h     |  2 ++
>  drivers/gpu/drm/i915/display/intel_dp_mst.c |  3 +-
>  3 files changed, 30 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index 23434d0aba188..9cd675c6d0ee8 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -383,6 +383,22 @@ int intel_dp_effective_data_rate(int pixel_clock, int
> bpp_x16,
>  				1000000 * 16 * 8);
>  }
> 
> +/**
> + * intel_dp_max_link_data_rate: Calculate the maximum rate for the
> +given link params
> + * @intel_dp: Intel DP object
> + * @max_dprx_rate: Maximum data rate of the DPRX
> + * @max_dprx_lanes: Maximum lane count of the DPRX
> + *
> + * Calculate the maximum data rate for the provided link parameters.
> + *
> + * Returns the maximum data rate in kBps units.
> + */
> +int intel_dp_max_link_data_rate(struct intel_dp *intel_dp,
> +				int max_dprx_rate, int max_dprx_lanes) {
> +	return drm_dp_max_dprx_data_rate(max_dprx_rate, max_dprx_lanes); }
> +
>  bool intel_dp_can_bigjoiner(struct intel_dp *intel_dp)  {
>  	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp); @@
> -612,7 +628,7 @@ static bool intel_dp_can_link_train_fallback_for_edp(struct
> intel_dp *intel_dp,
>  	int mode_rate, max_rate;
> 
>  	mode_rate = intel_dp_link_required(fixed_mode->clock, 18);
> -	max_rate = drm_dp_max_dprx_data_rate(link_rate, lane_count);
> +	max_rate = intel_dp_max_link_data_rate(intel_dp, link_rate,
> +lane_count);
>  	if (mode_rate > max_rate)
>  		return false;
> 
> @@ -1214,7 +1230,8 @@ intel_dp_mode_valid(struct drm_connector
> *_connector,
>  	max_link_clock = intel_dp_max_link_rate(intel_dp);
>  	max_lanes = intel_dp_max_lane_count(intel_dp);
> 
> -	max_rate = drm_dp_max_dprx_data_rate(max_link_clock, max_lanes);
> +	max_rate = intel_dp_max_link_data_rate(intel_dp, max_link_clock,
> +max_lanes);
> +
>  	mode_rate = intel_dp_link_required(target_clock,
> 
> intel_dp_mode_min_output_bpp(connector, mode));
> 
> @@ -1564,8 +1581,10 @@ intel_dp_compute_link_config_wide(struct intel_dp
> *intel_dp,
>  			for (lane_count = limits->min_lane_count;
>  			     lane_count <= limits->max_lane_count;
>  			     lane_count <<= 1) {
> -				link_avail =
> drm_dp_max_dprx_data_rate(link_rate,
> -
> lane_count);
> +				link_avail =
> intel_dp_max_link_data_rate(intel_dp,
> +
> link_rate,
> +
> lane_count);
> +
> 
>  				if (mode_rate <= link_avail) {
>  					pipe_config->lane_count = lane_count;
> @@ -2422,8 +2441,9 @@ intel_dp_compute_link_config(struct intel_encoder
> *encoder,
>  		    pipe_config->pipe_bpp,
>  		    BPP_X16_ARGS(pipe_config->dsc.compressed_bpp_x16),
>  		    intel_dp_config_required_rate(pipe_config),
> -		    drm_dp_max_dprx_data_rate(pipe_config->port_clock,
> -					      pipe_config->lane_count));
> +		    intel_dp_max_link_data_rate(intel_dp,
> +						pipe_config->port_clock,
> +						pipe_config->lane_count));
> 
>  	return 0;
>  }
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.h
> b/drivers/gpu/drm/i915/display/intel_dp.h
> index 49553e43add22..8b0dfbf06afff 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.h
> +++ b/drivers/gpu/drm/i915/display/intel_dp.h
> @@ -117,6 +117,8 @@ bool intel_dp_get_colorimetry_status(struct intel_dp
> *intel_dp);  int intel_dp_link_required(int pixel_clock, int bpp);  int
> intel_dp_effective_data_rate(int pixel_clock, int bpp_x16,
>  				 int bw_overhead);
> +int intel_dp_max_link_data_rate(struct intel_dp *intel_dp,
> +				int max_dprx_rate, int max_dprx_lanes);
>  bool intel_dp_can_bigjoiner(struct intel_dp *intel_dp);  bool
> intel_dp_needs_vsc_sdp(const struct intel_crtc_state *crtc_state,
>  			    const struct drm_connector_state *conn_state); diff --
> git a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index cfcc157b7d41d..520393dc8b453 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -1295,7 +1295,8 @@ intel_dp_mst_mode_valid_ctx(struct drm_connector
> *connector,
>  	max_link_clock = intel_dp_max_link_rate(intel_dp);
>  	max_lanes = intel_dp_max_lane_count(intel_dp);
> 
> -	max_rate = drm_dp_max_dprx_data_rate(max_link_clock, max_lanes);
> +	max_rate = intel_dp_max_link_data_rate(intel_dp,
> +					       max_link_clock, max_lanes);
>  	mode_rate = intel_dp_link_required(mode->clock, min_bpp);
> 
>  	ret = drm_modeset_lock(&mgr->base.lock, ctx);
> --
> 2.39.2