On Fri, Jan 31, 2025 at 02:49:57PM +0200, Jani Nikula wrote:
> Try to keep the variables in the same domain a bit longer to reduce
> juggling between integers and .4 fixed point. Change parameter order to
> min, max while at it.
>
> For now, keep the juggling in dsc_compute_compressed_bpp() ensure
> min/max will always have 0 fractional part. To be fixed later.
>
> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Reviewed-by: Imre Deak <imre.deak@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/display/intel_dp.c | 28 ++++++++++++++-----------
> 1 file changed, 16 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 02d1a5453b46..b13d806c9de7 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -2077,8 +2077,8 @@ static int
> icl_dsc_compute_link_config(struct intel_dp *intel_dp,
> struct intel_crtc_state *pipe_config,
> const struct link_config_limits *limits,
> - int dsc_max_bpp,
> - int dsc_min_bpp,
> + int min_bpp_x16,
> + int max_bpp_x16,
> int pipe_bpp,
> int timeslots)
> {
> @@ -2086,11 +2086,11 @@ icl_dsc_compute_link_config(struct intel_dp *intel_dp,
> int output_bpp = intel_dp_output_bpp(pipe_config->output_format, pipe_bpp);
>
> /* Compressed BPP should be less than the Input DSC bpp */
> - dsc_max_bpp = min(dsc_max_bpp, output_bpp - 1);
> + 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] < dsc_min_bpp ||
> - valid_dsc_bpp[i] > dsc_max_bpp)
> + if (valid_dsc_bpp[i] < fxp_q4_to_int(min_bpp_x16) ||
> + valid_dsc_bpp[i] > fxp_q4_to_int(max_bpp_x16))
> continue;
>
> ret = dsc_compute_link_config(intel_dp,
> @@ -2119,8 +2119,8 @@ 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 dsc_max_bpp,
> - int dsc_min_bpp,
> + int min_bpp_x16,
> + int max_bpp_x16,
> int pipe_bpp,
> int timeslots)
> {
> @@ -2132,10 +2132,9 @@ xelpd_dsc_compute_link_config(struct intel_dp *intel_dp,
> bpp_step_x16 = intel_dp_dsc_bpp_step_x16(connector);
>
> /* Compressed BPP should be less than the Input DSC bpp */
> - dsc_max_bpp = min(dsc_max_bpp << 4, (output_bpp << 4) - bpp_step_x16);
> - dsc_min_bpp = dsc_min_bpp << 4;
> + max_bpp_x16 = min(max_bpp_x16, fxp_q4_from_int(output_bpp) - bpp_step_x16);
>
> - for (bpp_x16 = dsc_max_bpp; bpp_x16 >= dsc_min_bpp; bpp_x16 -= 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))
> continue;
> @@ -2168,6 +2167,7 @@ static int dsc_compute_compressed_bpp(struct intel_dp *intel_dp,
> const struct drm_display_mode *adjusted_mode = &pipe_config->hw.adjusted_mode;
> int dsc_min_bpp;
> int dsc_max_bpp;
> + int min_bpp_x16, max_bpp_x16;
> int dsc_joiner_max_bpp;
> int num_joined_pipes = intel_crtc_num_joined_pipes(pipe_config);
>
> @@ -2178,11 +2178,15 @@ static int dsc_compute_compressed_bpp(struct intel_dp *intel_dp,
> num_joined_pipes);
> dsc_max_bpp = min(dsc_joiner_max_bpp, fxp_q4_to_int(limits->link.max_bpp_x16));
>
> + /* FIXME: remove the round trip via integers */
> + min_bpp_x16 = fxp_q4_from_int(dsc_min_bpp);
> + max_bpp_x16 = fxp_q4_from_int(dsc_max_bpp);
> +
> if (DISPLAY_VER(display) >= 13)
> return xelpd_dsc_compute_link_config(intel_dp, connector, pipe_config, limits,
> - dsc_max_bpp, dsc_min_bpp, pipe_bpp, timeslots);
> + min_bpp_x16, max_bpp_x16, pipe_bpp, timeslots);
> return icl_dsc_compute_link_config(intel_dp, pipe_config, limits,
> - dsc_max_bpp, dsc_min_bpp, pipe_bpp, timeslots);
> + min_bpp_x16, max_bpp_x16, pipe_bpp, timeslots);
> }
>
> int intel_dp_dsc_min_src_input_bpc(void)
> --
> 2.39.5
>
