drm/amd/display: Manually adjust strobe for DCN303

commit a9a1ac44074ff8cab7d519277f93341e14557f83 upstream.

why:
DCN303's 4 channel SOC BB causes problems at strobe

how:
workaround to manually adjust strobe calculation using FCLK
restrict.

Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Agustin Gutierrez <agustin.gutierrez@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Martin Leung <Martin.Leung@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/amd/display/dc/dcn303/dcn303_resource.c b/drivers/gpu/drm/amd/display/dc/dcn303/dcn303_resource.c
index 7aad034..67d8341 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/dcn303/dcn303_resource.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn303/dcn303_resource.c
@@ -1344,6 +1344,20 @@ void dcn303_update_bw_bounding_box(struct dc *dc, struct clk_bw_params *bw_param
                        dcn3_03_soc.clock_limits[i].phyclk_d18_mhz = dcn3_03_soc.clock_limits[0].phyclk_d18_mhz;
                        dcn3_03_soc.clock_limits[i].dscclk_mhz = dcn3_03_soc.clock_limits[0].dscclk_mhz;
                }
+
+               // WA: patch strobe modes to compensate for DCN303 BW issue
+               if (dcn3_03_soc.num_chans <= 4) {
+                       for (i = 0; i < dcn3_03_soc.num_states; i++) {
+                               if (dcn3_03_soc.clock_limits[i].dram_speed_mts > 1700)
+                                       break;
+
+                               if (dcn3_03_soc.clock_limits[i].dram_speed_mts >= 1500) {
+                                       dcn3_03_soc.clock_limits[i].dcfclk_mhz = 100;
+                                       dcn3_03_soc.clock_limits[i].fabricclk_mhz = 100;
+                               }
+                       }
+               }
+
                /* re-init DML with updated bb */
                dml_init_instance(&dc->dml, &dcn3_03_soc, &dcn3_03_ip, DML_PROJECT_DCN30);
                if (dc->current_state)