drm/amd/display: Force uclk to max for every state

Workaround for now to avoid underflow.

The uclk switch time should really be bumped up to 404, but doing so
would expose p-state hang issues for higher bandwidth display
configurations.

Signed-off-by: Nicholas Kazlauskas <[email protected]>
Signed-off-by: Leo Li <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

Author: Nicholas Kazlauskas

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_pp_smu.c

@@ -911,11 +911,11 @@ void dm_pp_get_funcs(
 		/* todo set_pme_wa_enable cause 4k@6ohz display not light up */
 		funcs->nv_funcs.set_pme_wa_enable = NULL;
 		/* todo debug waring message */
-		funcs->nv_funcs.set_hard_min_uclk_by_freq = NULL;
+		funcs->nv_funcs.set_hard_min_uclk_by_freq = pp_nv_set_hard_min_uclk_by_freq;
 		/* todo  compare data with window driver*/
-		funcs->nv_funcs.get_maximum_sustainable_clocks = NULL;
+		funcs->nv_funcs.get_maximum_sustainable_clocks = pp_nv_get_maximum_sustainable_clocks;
 		/*todo  compare data with window driver */
-		funcs->nv_funcs.get_uclk_dpm_states = NULL;
+		funcs->nv_funcs.get_uclk_dpm_states = pp_nv_get_uclk_dpm_states;
 		break;
 #endif
 	default:

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_resource.c

@@ -2576,6 +2576,9 @@ static void cap_soc_clocks(
 						&& max_clocks.uClockInKhz != 0)
 			bb->clock_limits[i].dram_speed_mts = (max_clocks.uClockInKhz / 1000) * 16;
 
+		// HACK: Force every uclk to max for now to "disable" uclk switching.
+		bb->clock_limits[i].dram_speed_mts = (max_clocks.uClockInKhz / 1000) * 16;
+
 		if ((bb->clock_limits[i].fabricclk_mhz > (max_clocks.fabricClockInKhz / 1000))
 						&& max_clocks.fabricClockInKhz != 0)
 			bb->clock_limits[i].fabricclk_mhz = (max_clocks.fabricClockInKhz / 1000);
@@ -2783,6 +2786,8 @@ static bool init_soc_bounding_box(struct dc *dc,
 				le32_to_cpu(bb->vmm_page_size_bytes);
 		dcn2_0_soc.dram_clock_change_latency_us =
 				fixed16_to_double_to_cpu(bb->dram_clock_change_latency_us);
+		// HACK!! Lower uclock latency switch time so we don't switch
+		dcn2_0_soc.dram_clock_change_latency_us = 10;
 		dcn2_0_soc.writeback_dram_clock_change_latency_us =
 				fixed16_to_double_to_cpu(bb->writeback_dram_clock_change_latency_us);
 		dcn2_0_soc.return_bus_width_bytes =
@@ -2824,6 +2829,7 @@ static bool init_soc_bounding_box(struct dc *dc,
 		struct pp_smu_nv_clock_table max_clocks = {0};
 		unsigned int uclk_states[8] = {0};
 		unsigned int num_states = 0;
+		int i;
 		enum pp_smu_status status;
 		bool clock_limits_available = false;
 		bool uclk_states_available = false;
@@ -2845,6 +2851,10 @@ static bool init_soc_bounding_box(struct dc *dc,
 			clock_limits_available = (status == PP_SMU_RESULT_OK);
 		}
 
+		// HACK: Use the max uclk_states value for all elements.
+		for (i = 0; i < num_states; i++)
+			uclk_states[i] = uclk_states[num_states - 1];
+
 		if (clock_limits_available && uclk_states_available && num_states)
 			update_bounding_box(dc, &dcn2_0_soc, &max_clocks, uclk_states, num_states);
 		else if (clock_limits_available)