drm/amd/display: Fix DCN 3.01 DSCCLK validation

[why]
DSCCLK validation is not necessary because DSCCLK is derrived from
DISPCLK, therefore if DISPCLK validation passes, DSCCLK is valid, too.
Doing DSCLK validation in addition to DISPCLK leads to modes being
wrongly rejected when DSCCLK was incorrectly set outside of DML.

[how]
Remove DSCCLK validation because it's implicitly validated under DISPCLK
Signed-off-by: Nikola Cornij <nikola.cornij@amd.com>
Reviewed-by: Dmytro Laktyushkin <Dmytro.Laktyushkin@amd.com>
Acked-by: Stylon Wang <stylon.wang@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dml/dcn30/display_mode_vba_30.c

@@ -64,6 +64,7 @@ typedef struct {
 #define BPP_INVALID 0
 #define BPP_BLENDED_PIPE 0xffffffff
 #define DCN30_MAX_DSC_IMAGE_WIDTH 5184
+#define DCN30_MAX_FMT_420_BUFFER_WIDTH 4096
 
 static void DisplayPipeConfiguration(struct display_mode_lib *mode_lib);
 static void DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation(
@@ -3987,19 +3988,30 @@ void dml30_ModeSupportAndSystemConfigurationFull(struct display_mode_lib *mode_l
 				} else if (v->PlaneRequiredDISPCLKWithoutODMCombine > v->MaxDispclkRoundedDownToDFSGranularity) {
 					v->ODMCombineEnablePerState[i][k] = dm_odm_combine_mode_2to1;
 					v->PlaneRequiredDISPCLK = v->PlaneRequiredDISPCLKWithODMCombine2To1;
-				} else if (v->DSCEnabled[k] && (v->HActive[k] > DCN30_MAX_DSC_IMAGE_WIDTH)) {
-					v->ODMCombineEnablePerState[i][k] = dm_odm_combine_mode_2to1;
-					v->PlaneRequiredDISPCLK = v->PlaneRequiredDISPCLKWithODMCombine2To1;
 				} else {
 					v->ODMCombineEnablePerState[i][k] = dm_odm_combine_mode_disabled;
 					v->PlaneRequiredDISPCLK = v->PlaneRequiredDISPCLKWithoutODMCombine;
-					/*420 format workaround*/
-					if (v->HActive[k] > 4096 && v->OutputFormat[k] == dm_420) {
+				}
+				if (v->DSCEnabled[k] && v->HActive[k] > DCN30_MAX_DSC_IMAGE_WIDTH
+						&& v->ODMCombineEnablePerState[i][k] != dm_odm_combine_mode_4to1) {
+					if (v->HActive[k] / 2 > DCN30_MAX_DSC_IMAGE_WIDTH) {
+						v->ODMCombineEnablePerState[i][k] = dm_odm_combine_mode_4to1;
+						v->PlaneRequiredDISPCLK = v->PlaneRequiredDISPCLKWithODMCombine4To1;
+					} else {
+						v->ODMCombineEnablePerState[i][k] = dm_odm_combine_mode_2to1;
+						v->PlaneRequiredDISPCLK = v->PlaneRequiredDISPCLKWithODMCombine2To1;
+					}
+				}
+				if (v->OutputFormat[k] == dm_420 && v->HActive[k] > DCN30_MAX_FMT_420_BUFFER_WIDTH
+						&& v->ODMCombineEnablePerState[i][k] != dm_odm_combine_mode_4to1) {
+					if (v->HActive[k] / 2 > DCN30_MAX_FMT_420_BUFFER_WIDTH) {
+						v->ODMCombineEnablePerState[i][k] = dm_odm_combine_mode_4to1;
+						v->PlaneRequiredDISPCLK = v->PlaneRequiredDISPCLKWithODMCombine4To1;
+					} else {
 						v->ODMCombineEnablePerState[i][k] = dm_odm_combine_mode_2to1;
 						v->PlaneRequiredDISPCLK = v->PlaneRequiredDISPCLKWithODMCombine2To1;
 					}
 				}
-
 				if (v->ODMCombineEnablePerState[i][k] == dm_odm_combine_mode_4to1) {
 					v->MPCCombine[i][j][k] = false;
 					v->NoOfDPP[i][j][k] = 4;
@@ -4281,42 +4293,8 @@ void dml30_ModeSupportAndSystemConfigurationFull(struct display_mode_lib *mode_l
 		}
 	}
 
-	for (i = 0; i < v->soc.num_states; i++) {
-		v->DSCCLKRequiredMoreThanSupported[i] = false;
-		for (k = 0; k <= v->NumberOfActivePlanes - 1; k++) {
-			if (v->BlendingAndTiming[k] == k) {
-				if (v->Output[k] == dm_dp || v->Output[k] == dm_edp) {
-					if (v->OutputFormat[k] == dm_420) {
-						v->DSCFormatFactor = 2;
-					} else if (v->OutputFormat[k] == dm_444) {
-						v->DSCFormatFactor = 1;
-					} else if (v->OutputFormat[k] == dm_n422) {
-						v->DSCFormatFactor = 2;
-					} else {
-						v->DSCFormatFactor = 1;
-					}
-					if (v->RequiresDSC[i][k] == true) {
-						if (v->ODMCombineEnablePerState[i][k] == dm_odm_combine_mode_4to1) {
-							if (v->PixelClockBackEnd[k] / 12.0 / v->DSCFormatFactor
-									> (1.0 - v->DISPCLKDPPCLKDSCCLKDownSpreading / 100.0) * v->MaxDSCCLK[i]) {
-								v->DSCCLKRequiredMoreThanSupported[i] = true;
-							}
-						} else if (v->ODMCombineEnablePerState[i][k] == dm_odm_combine_mode_2to1) {
-							if (v->PixelClockBackEnd[k] / 6.0 / v->DSCFormatFactor
-									> (1.0 - v->DISPCLKDPPCLKDSCCLKDownSpreading / 100.0) * v->MaxDSCCLK[i]) {
-								v->DSCCLKRequiredMoreThanSupported[i] = true;
-							}
-						} else {
-							if (v->PixelClockBackEnd[k] / 3.0 / v->DSCFormatFactor
-									> (1.0 - v->DISPCLKDPPCLKDSCCLKDownSpreading / 100.0) * v->MaxDSCCLK[i]) {
-								v->DSCCLKRequiredMoreThanSupported[i] = true;
-							}
-						}
-					}
-				}
-			}
-		}
-	}
+	/* Skip dscclk validation: as long as dispclk is supported, dscclk is also implicitly supported */
+
 	for (i = 0; i < v->soc.num_states; i++) {
 		v->NotEnoughDSCUnits[i] = false;
 		v->TotalDSCUnitsRequired = 0.0;
@@ -5319,7 +5297,7 @@ void dml30_ModeSupportAndSystemConfigurationFull(struct display_mode_lib *mode_l
 		for (j = 0; j < 2; j++) {
 			if (v->ScaleRatioAndTapsSupport == 1 && v->SourceFormatPixelAndScanSupport == 1 && v->ViewportSizeSupport[i][j] == 1
 					&& v->DIOSupport[i] == 1 && v->ODMCombine4To1SupportCheckOK[i] == 1
-					&& v->NotEnoughDSCUnits[i] == 0 && v->DSCCLKRequiredMoreThanSupported[i] == 0
+					&& v->NotEnoughDSCUnits[i] == 0
 					&& v->DTBCLKRequiredMoreThanSupported[i] == 0
 					&& v->ROBSupport[i][j] == 1 && v->DISPCLK_DPPCLK_Support[i][j] == 1 && v->TotalAvailablePipesSupport[i][j] == 1
 					&& EnoughWritebackUnits == 1 && WritebackModeSupport == 1