Re: [PATCH 05/14] drm/i915/dp: Move max DSC BPP reduction one level higher

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

On Fri, Jan 31, 2025 at 02:49:58PM +0200, Jani Nikula wrote:
> Now that {icl,xelpd}_dsc_compute_link_config() take .4 fixed point as
> parameter, move the common max DSC BPP reduction one level higher. Use
> intel_dp_dsc_bpp_step() to compute the step, and pass on to both
> platform specific functions. (Though it's unused for now in
> icl_dsc_compute_link_config()).
> 
> We can drop the pipe_bpp and connector parameters.
> 
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>

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

> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 32 +++++++++++--------------
>  1 file changed, 14 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index b13d806c9de7..4e7b3dd4067c 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -2079,14 +2079,10 @@ icl_dsc_compute_link_config(struct intel_dp *intel_dp,
>  			    const struct link_config_limits *limits,
>  			    int min_bpp_x16,
>  			    int max_bpp_x16,
> -			    int pipe_bpp,
> +			    int bpp_step_x16,
>  			    int timeslots)
>  {
>  	int i, ret;
> -	int output_bpp = intel_dp_output_bpp(pipe_config->output_format, pipe_bpp);
> -
> -	/* Compressed BPP should be less than the Input DSC bpp */
> -	max_bpp_x16 = min(max_bpp_x16, fxp_q4_from_int(output_bpp - 1));
>  
>  	for (i = ARRAY_SIZE(valid_dsc_bpp) - 1; i >= 0; i--) {
>  		if (valid_dsc_bpp[i] < fxp_q4_to_int(min_bpp_x16) ||
> @@ -2116,24 +2112,17 @@ icl_dsc_compute_link_config(struct intel_dp *intel_dp,
>   */
>  static int
>  xelpd_dsc_compute_link_config(struct intel_dp *intel_dp,
> -			      const struct intel_connector *connector,
>  			      struct intel_crtc_state *pipe_config,
>  			      const struct link_config_limits *limits,
>  			      int min_bpp_x16,
>  			      int max_bpp_x16,
> -			      int pipe_bpp,
> +			      int bpp_step_x16,
>  			      int timeslots)
>  {
>  	struct intel_display *display = to_intel_display(intel_dp);
> -	int output_bpp = intel_dp_output_bpp(pipe_config->output_format, pipe_bpp);
> -	int bpp_x16, bpp_step_x16;
> +	int bpp_x16;
>  	int ret;
>  
> -	bpp_step_x16 = intel_dp_dsc_bpp_step_x16(connector);
> -
> -	/* Compressed BPP should be less than the Input DSC bpp */
> -	max_bpp_x16 = min(max_bpp_x16, fxp_q4_from_int(output_bpp) - bpp_step_x16);
> -
>  	for (bpp_x16 = max_bpp_x16; bpp_x16 >= min_bpp_x16; bpp_x16 -= bpp_step_x16) {
>  		if (intel_dp->force_dsc_fractional_bpp_en &&
>  		    !fxp_q4_to_frac(bpp_x16))
> @@ -2165,9 +2154,10 @@ static int dsc_compute_compressed_bpp(struct intel_dp *intel_dp,
>  {
>  	struct intel_display *display = to_intel_display(intel_dp);
>  	const struct drm_display_mode *adjusted_mode = &pipe_config->hw.adjusted_mode;
> +	int output_bpp;
>  	int dsc_min_bpp;
>  	int dsc_max_bpp;
> -	int min_bpp_x16, max_bpp_x16;
> +	int min_bpp_x16, max_bpp_x16, bpp_step_x16;
>  	int dsc_joiner_max_bpp;
>  	int num_joined_pipes = intel_crtc_num_joined_pipes(pipe_config);
>  
> @@ -2182,11 +2172,17 @@ static int dsc_compute_compressed_bpp(struct intel_dp *intel_dp,
>  	min_bpp_x16 = fxp_q4_from_int(dsc_min_bpp);
>  	max_bpp_x16 = fxp_q4_from_int(dsc_max_bpp);
>  
> +	bpp_step_x16 = intel_dp_dsc_bpp_step_x16(connector);
> +
> +	/* Compressed BPP should be less than the Input DSC bpp */
> +	output_bpp = intel_dp_output_bpp(pipe_config->output_format, pipe_bpp);
> +	max_bpp_x16 = min(max_bpp_x16, fxp_q4_from_int(output_bpp) - bpp_step_x16);
> +
>  	if (DISPLAY_VER(display) >= 13)
> -		return xelpd_dsc_compute_link_config(intel_dp, connector, pipe_config, limits,
> -						     min_bpp_x16, max_bpp_x16, pipe_bpp, timeslots);
> +		return xelpd_dsc_compute_link_config(intel_dp, pipe_config, limits,
> +						     min_bpp_x16, max_bpp_x16, bpp_step_x16, timeslots);
>  	return icl_dsc_compute_link_config(intel_dp, pipe_config, limits,
> -					   min_bpp_x16, max_bpp_x16, pipe_bpp, timeslots);
> +					   min_bpp_x16, max_bpp_x16, bpp_step_x16, timeslots);
>  }
>  
>  int intel_dp_dsc_min_src_input_bpc(void)
> -- 
> 2.39.5
>