drm/amd/display: Enable DSC Flag in MST Mode Validation

[WHY & HOW]
When dsc is possible, MST mode validation includes:
1. if maximum dsc compression cannot fit into end to end bw, mode pruned
2. if native bw cannot fit into end to end bw, try to enabled dsc to see
   whether a feasible dsc config can be found
3. if native bw can fit into end to end bw, mode supported

Reviewed-by: Wayne Lin <wayne.lin@amd.com>
Acked-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Fangzhi Zuo <jerry.zuo@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index ec87e31c6fe88e5e5544028e70a1165c8fd5f263..8d7d4024f28592d5f720c97d6dfb9026152a71e7 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -1602,9 +1602,8 @@ enum dc_status dm_dp_mst_is_port_support_mode(
        struct dc_link_settings cur_link_settings;
        unsigned int end_to_end_bw_in_kbps = 0;
        unsigned int upper_link_bw_in_kbps = 0, down_link_bw_in_kbps = 0;
-       unsigned int max_compressed_bw_in_kbps = 0;
        struct dc_dsc_bw_range bw_range = {0};
-       uint16_t full_pbn = aconnector->mst_output_port->full_pbn;
+       struct dc_dsc_config_options dsc_options = {0};
 
        /*
         * Consider the case with the depth of the mst topology tree is equal or less than 2
@@ -1620,30 +1619,39 @@ enum dc_status dm_dp_mst_is_port_support_mode(
           (aconnector->mst_output_port->passthrough_aux ||
            aconnector->dsc_aux == &aconnector->mst_output_port->aux)) {
                cur_link_settings = stream->link->verified_link_cap;
+               upper_link_bw_in_kbps = dc_link_bandwidth_kbps(aconnector->dc_link, &cur_link_settings);
+               down_link_bw_in_kbps = kbps_from_pbn(aconnector->mst_output_port->full_pbn);
 
-               upper_link_bw_in_kbps = dc_link_bandwidth_kbps(aconnector->dc_link,
-                                                              &cur_link_settings);
-               down_link_bw_in_kbps = kbps_from_pbn(full_pbn);
-
-               /* pick the bottleneck */
-               end_to_end_bw_in_kbps = min(upper_link_bw_in_kbps,
-                                           down_link_bw_in_kbps);
-
-               /*
-                * use the maximum dsc compression bandwidth as the required
-                * bandwidth for the mode
-                */
-               max_compressed_bw_in_kbps = bw_range.min_kbps;
+               /* pick the end to end bw bottleneck */
+               end_to_end_bw_in_kbps = min(upper_link_bw_in_kbps, down_link_bw_in_kbps);
 
-               if (end_to_end_bw_in_kbps < max_compressed_bw_in_kbps) {
-                       DRM_DEBUG_DRIVER("Mode does not fit into DSC pass-through bandwidth validation\n");
+               if (end_to_end_bw_in_kbps < bw_range.min_kbps) {
+                       DRM_DEBUG_DRIVER("maximum dsc compression cannot fit into end-to-end bandwidth\n");
                        return DC_FAIL_BANDWIDTH_VALIDATE;
                }
+
+               if (end_to_end_bw_in_kbps < bw_range.stream_kbps) {
+                       dc_dsc_get_default_config_option(stream->link->dc, &dsc_options);
+                       dsc_options.max_target_bpp_limit_override_x16 = aconnector->base.display_info.max_dsc_bpp * 16;
+                       if (dc_dsc_compute_config(stream->sink->ctx->dc->res_pool->dscs[0],
+                                       &stream->sink->dsc_caps.dsc_dec_caps,
+                                       &dsc_options,
+                                       end_to_end_bw_in_kbps,
+                                       &stream->timing,
+                                       dc_link_get_highest_encoding_format(stream->link),
+                                       &stream->timing.dsc_cfg)) {
+                               stream->timing.flags.DSC = 1;
+                               DRM_DEBUG_DRIVER("end-to-end bandwidth require dsc and dsc config found\n");
+                       } else {
+                               DRM_DEBUG_DRIVER("end-to-end bandwidth require dsc but dsc config not found\n");
+                               return DC_FAIL_BANDWIDTH_VALIDATE;
+                       }
+               }
        } else {
                /* check if mode could be supported within full_pbn */
                bpp = convert_dc_color_depth_into_bpc(stream->timing.display_color_depth) * 3;
                pbn = drm_dp_calc_pbn_mode(stream->timing.pix_clk_100hz / 10, bpp, false);
-               if (pbn > full_pbn)
+               if (pbn > aconnector->mst_output_port->full_pbn)
                        return DC_FAIL_BANDWIDTH_VALIDATE;
        }