drm/amd/display: use uclk pstate latency for fw assisted mclk validat…

…ion dcn32

[WHY?]
DCN32 uses fclk pstate watermarks for dummy pstate, and must always be
supported.

[HOW?]
Validation needs to be run with fclk pstate latency set
as the dummy pstate latency to get correct prefetch and bandwidth outputs.

Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Dillon Varone <Dillon.Varone@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>

drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c

@@ -1809,6 +1809,12 @@ void dcn32_calculate_wm_and_dlg_fpu(struct dc *dc, struct dc_state *context,
 			 */
 			context->bw_ctx.dml.soc.dram_clock_change_latency_us =
 					dc->clk_mgr->bw_params->wm_table.nv_entries[WM_A].dml_input.pstate_latency_us;
+			/* For DCN32/321 need to validate with fclk pstate change latency equal to dummy so
+			 * prefetch is scheduled correctly to account for dummy pstate.
+			 */
+			if (dummy_latency_index == 0)
+				context->bw_ctx.dml.soc.fclk_change_latency_us =
+						dc->clk_mgr->bw_params->dummy_pstate_table[dummy_latency_index].dummy_pstate_latency_us;
 			dcn32_internal_validate_bw(dc, context, pipes, &pipe_cnt, &vlevel, false);
 			maxMpcComb = context->bw_ctx.dml.vba.maxMpcComb;
 			dcfclk_from_fw_based_mclk_switching = context->bw_ctx.dml.vba.DCFCLKState[vlevel][context->bw_ctx.dml.vba.maxMpcComb];
@@ -1996,15 +2002,23 @@ void dcn32_calculate_wm_and_dlg_fpu(struct dc *dc, struct dc_state *context,
 
 	context->perf_params.stutter_period_us = context->bw_ctx.dml.vba.StutterPeriod;
 
+	if (context->bw_ctx.bw.dcn.clk.fw_based_mclk_switching && dummy_latency_index == 0)
+		context->bw_ctx.dml.soc.fclk_change_latency_us =
+				dc->clk_mgr->bw_params->dummy_pstate_table[dummy_latency_index].dummy_pstate_latency_us;
+
 	dcn32_calculate_dlg_params(dc, context, pipes, pipe_cnt, vlevel);
 
 	if (!pstate_en)
 		/* Restore full p-state latency */
 		context->bw_ctx.dml.soc.dram_clock_change_latency_us =
 				dc->clk_mgr->bw_params->wm_table.nv_entries[WM_A].dml_input.pstate_latency_us;
 
-	if (context->bw_ctx.bw.dcn.clk.fw_based_mclk_switching)
+	if (context->bw_ctx.bw.dcn.clk.fw_based_mclk_switching) {
 		dcn30_setup_mclk_switch_using_fw_based_vblank_stretch(dc, context);
+		if (dummy_latency_index == 0)
+			context->bw_ctx.dml.soc.fclk_change_latency_us =
+					dc->clk_mgr->bw_params->wm_table.nv_entries[WM_A].dml_input.fclk_change_latency_us;
+	}
 }
 
 static void dcn32_get_optimal_dcfclk_fclk_for_uclk(unsigned int uclk_mts,