Re: [PATCH 3/6] drm/i915/mst: change where lane_count and port_clock are set

[Imre Deak <imre.deak@intel.com>]

On Wed, Jan 29, 2025 at 04:46:35PM +0200, Jani Nikula wrote:
> Semantically mst_stream_find_vcpi_slots_for_bpp() does not seem like the
> place to make decisions about lane_count and port_clock. Move them to
> the callers, and remove the limits parameter that becomes unused.
> 
> This leads to slight duplication, but a) this makes further refactoring
> easier, and b) also the SST code sets link parameters in different
> places for uncompressed and compressed paths.
> 
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Reviewed-by: Imre Deak <imre.deak@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_dp_mst.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index 98d7cdddfead..ea1b05224c06 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -362,7 +362,6 @@ int intel_dp_mtp_tu_compute_config(struct intel_dp *intel_dp,
>  static int mst_stream_find_vcpi_slots_for_bpp(struct intel_dp *intel_dp,
>  					      struct intel_crtc_state *crtc_state,
>  					      int max_bpp, int min_bpp,
> -					      const struct link_config_limits *limits,
>  					      struct drm_connector_state *conn_state,
>  					      int step, bool dsc)
>  {
> @@ -373,9 +372,6 @@ static int mst_stream_find_vcpi_slots_for_bpp(struct intel_dp *intel_dp,
>  	if (IS_ERR(mst_state))
>  		return PTR_ERR(mst_state);
>  
> -	crtc_state->lane_count = limits->max_lane_count;
> -	crtc_state->port_clock = limits->max_rate;
> -
>  	mst_state->pbn_div = drm_dp_get_vc_payload_bw(crtc_state->port_clock,
>  						      crtc_state->lane_count);
>  
> @@ -388,6 +384,9 @@ static int mst_stream_compute_link_config(struct intel_dp *intel_dp,
>  					  struct drm_connector_state *conn_state,
>  					  const struct link_config_limits *limits)
>  {
> +	crtc_state->lane_count = limits->max_lane_count;
> +	crtc_state->port_clock = limits->max_rate;
> +
>  	/*
>  	 * FIXME: allocate the BW according to link_bpp, which in the case of
>  	 * YUV420 is only half of the pipe bpp value.
> @@ -395,7 +394,6 @@ static int mst_stream_compute_link_config(struct intel_dp *intel_dp,
>  	return mst_stream_find_vcpi_slots_for_bpp(intel_dp, crtc_state,
>  						  fxp_q4_to_int(limits->link.max_bpp_x16),
>  						  fxp_q4_to_int(limits->link.min_bpp_x16),
> -						  limits,
>  						  conn_state, 2 * 3, false);
>  }
>  
> @@ -453,8 +451,11 @@ static int mst_stream_dsc_compute_link_config(struct intel_dp *intel_dp,
>  	min_compressed_bpp = intel_dp_dsc_nearest_valid_bpp(display, min_compressed_bpp,
>  							    crtc_state->pipe_bpp);
>  
> +	crtc_state->lane_count = limits->max_lane_count;
> +	crtc_state->port_clock = limits->max_rate;
> +
>  	return mst_stream_find_vcpi_slots_for_bpp(intel_dp, crtc_state, max_compressed_bpp,
> -						  min_compressed_bpp, limits,
> +						  min_compressed_bpp,
>  						  conn_state, 1, true);
>  }
>  
> -- 
> 2.39.5
>