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From:   Harry Wentland <harry.wentland@amd.com>
To:     <amd-gfx@lists.freedesktop.org>
CC:     <ndesaulniers@google.com>, <torvalds@linux-foundation.org>,
        <linux-kernel@vger.kernel.org>, <arnd@kernel.org>,
        <sunpeng.li@amd.com>, <alexander.deucher@amd.com>,
        <christian.koenig@amd.com>, <Xinhui.Pan@amd.com>,
        <nathan@kernel.org>, <linux@roeck-us.net>, <llvm@lists.linux.dev>,
        Harry Wentland <harry.wentland@amd.com>
Subject: [PATCH] drm/amd/display: Reduce stack size for dml21_ModeSupportAndSystemConfigurationFull
Date:   Tue, 14 Sep 2021 17:05:08 -0400
Message-ID: <20210914210508.10627-1-harry.wentland@amd.com>
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[Why & How]
With Werror enabled in the kernel we were failing the clang build since
dml21_ModeSupportAndSystemConfigurationFull's stack frame is 1064 when
building with clang, and exceeding the default 1024 stack frame limit.

The culprit seems to be the Pipe struct, so pull the relevant block
out into its own sub-function.

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Fixes: 3fe617ccafd6 ("Enable '-Werror' by default for all kernel builds")
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: amd-gfx@lists.freedesktop.org
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Leo Li <sunpeng.li@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Xinhui Pan <Xinhui.Pan@amd.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: llvm@lists.linux.dev
---
 .../dc/dml/dcn21/display_mode_vba_21.c        | 236 +++++++++---------
 1 file changed, 123 insertions(+), 113 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dml/dcn21/display_mode_vba_21.c b/drivers/gpu/drm/amd/display/dc/dml/dcn21/display_mode_vba_21.c
index 4136eb8256cb..8a7485e21d53 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/dcn21/display_mode_vba_21.c
+++ b/drivers/gpu/drm/amd/display/dc/dml/dcn21/display_mode_vba_21.c
@@ -3394,6 +3394,127 @@ static unsigned int TruncToValidBPP(
 	}
 }
 
+
+static noinline void CalculatePrefetchSchedulePerPlane(
+		struct display_mode_lib *mode_lib,
+		int i,
+		unsigned j,
+		unsigned k)
+{
+	struct vba_vars_st *locals = &mode_lib->vba;
+	Pipe myPipe;
+	HostVM myHostVM;
+
+	if (mode_lib->vba.XFCEnabled[k] == true) {
+		mode_lib->vba.XFCRemoteSurfaceFlipDelay =
+				CalculateRemoteSurfaceFlipDelay(
+						mode_lib,
+						mode_lib->vba.VRatio[k],
+						locals->SwathWidthYThisState[k],
+						dml_ceil(locals->BytePerPixelInDETY[k], 1.0),
+						mode_lib->vba.HTotal[k] / mode_lib->vba.PixelClock[k],
+						mode_lib->vba.XFCTSlvVupdateOffset,
+						mode_lib->vba.XFCTSlvVupdateWidth,
+						mode_lib->vba.XFCTSlvVreadyOffset,
+						mode_lib->vba.XFCXBUFLatencyTolerance,
+						mode_lib->vba.XFCFillBWOverhead,
+						mode_lib->vba.XFCSlvChunkSize,
+						mode_lib->vba.XFCBusTransportTime,
+						mode_lib->vba.TimeCalc,
+						mode_lib->vba.TWait,
+						&mode_lib->vba.SrcActiveDrainRate,
+						&mode_lib->vba.TInitXFill,
+						&mode_lib->vba.TslvChk);
+	} else {
+		mode_lib->vba.XFCRemoteSurfaceFlipDelay = 0.0;
+	}
+
+	myPipe.DPPCLK = locals->RequiredDPPCLK[i][j][k];
+	myPipe.DISPCLK = locals->RequiredDISPCLK[i][j];
+	myPipe.PixelClock = mode_lib->vba.PixelClock[k];
+	myPipe.DCFCLKDeepSleep = mode_lib->vba.ProjectedDCFCLKDeepSleep[0][0];
+	myPipe.DPPPerPlane = locals->NoOfDPP[i][j][k];
+	myPipe.ScalerEnabled = mode_lib->vba.ScalerEnabled[k];
+	myPipe.SourceScan = mode_lib->vba.SourceScan[k];
+	myPipe.BlockWidth256BytesY = locals->Read256BlockWidthY[k];
+	myPipe.BlockHeight256BytesY = locals->Read256BlockHeightY[k];
+	myPipe.BlockWidth256BytesC = locals->Read256BlockWidthC[k];
+	myPipe.BlockHeight256BytesC = locals->Read256BlockHeightC[k];
+	myPipe.InterlaceEnable = mode_lib->vba.Interlace[k];
+	myPipe.NumberOfCursors = mode_lib->vba.NumberOfCursors[k];
+	myPipe.VBlank = mode_lib->vba.VTotal[k] - mode_lib->vba.VActive[k];
+	myPipe.HTotal = mode_lib->vba.HTotal[k];
+
+
+	myHostVM.Enable = mode_lib->vba.HostVMEnable;
+	myHostVM.MaxPageTableLevels = mode_lib->vba.HostVMMaxPageTableLevels;
+	myHostVM.CachedPageTableLevels = mode_lib->vba.HostVMCachedPageTableLevels;
+
+
+	mode_lib->vba.IsErrorResult[i][j][k] = CalculatePrefetchSchedule(
+			mode_lib,
+			mode_lib->vba.PercentOfIdealDRAMFabricAndSDPPortBWReceivedAfterUrgLatencyPixelMixedWithVMData,
+			mode_lib->vba.PercentOfIdealDRAMFabricAndSDPPortBWReceivedAfterUrgLatencyVMDataOnly,
+			&myPipe,
+			locals->DSCDelayPerState[i][k],
+			mode_lib->vba.DPPCLKDelaySubtotal,
+			mode_lib->vba.DPPCLKDelaySCL,
+			mode_lib->vba.DPPCLKDelaySCLLBOnly,
+			mode_lib->vba.DPPCLKDelayCNVCFormater,
+			mode_lib->vba.DPPCLKDelayCNVCCursor,
+			mode_lib->vba.DISPCLKDelaySubtotal,
+			locals->SwathWidthYThisState[k] / mode_lib->vba.HRatio[k],
+			mode_lib->vba.OutputFormat[k],
+			mode_lib->vba.MaxInterDCNTileRepeaters,
+			dml_min(mode_lib->vba.MaxVStartup, locals->MaximumVStartup[0][0][k]),
+			locals->MaximumVStartup[0][0][k],
+			mode_lib->vba.GPUVMMaxPageTableLevels,
+			mode_lib->vba.GPUVMEnable,
+			&myHostVM,
+			mode_lib->vba.DynamicMetadataEnable[k],
+			mode_lib->vba.DynamicMetadataLinesBeforeActiveRequired[k],
+			mode_lib->vba.DynamicMetadataTransmittedBytes[k],
+			mode_lib->vba.DCCEnable[k],
+			mode_lib->vba.UrgentLatency,
+			mode_lib->vba.ExtraLatency,
+			mode_lib->vba.TimeCalc,
+			locals->PDEAndMetaPTEBytesPerFrame[0][0][k],
+			locals->MetaRowBytes[0][0][k],
+			locals->DPTEBytesPerRow[0][0][k],
+			locals->PrefetchLinesY[0][0][k],
+			locals->SwathWidthYThisState[k],
+			locals->BytePerPixelInDETY[k],
+			locals->PrefillY[k],
+			locals->MaxNumSwY[k],
+			locals->PrefetchLinesC[0][0][k],
+			locals->BytePerPixelInDETC[k],
+			locals->PrefillC[k],
+			locals->MaxNumSwC[k],
+			locals->SwathHeightYThisState[k],
+			locals->SwathHeightCThisState[k],
+			mode_lib->vba.TWait,
+			mode_lib->vba.XFCEnabled[k],
+			mode_lib->vba.XFCRemoteSurfaceFlipDelay,
+			mode_lib->vba.ProgressiveToInterlaceUnitInOPP,
+			&locals->dst_x_after_scaler,
+			&locals->dst_y_after_scaler,
+			&locals->LineTimesForPrefetch[k],
+			&locals->PrefetchBW[k],
+			&locals->LinesForMetaPTE[k],
+			&locals->LinesForMetaAndDPTERow[k],
+			&locals->VRatioPreY[i][j][k],
+			&locals->VRatioPreC[i][j][k],
+			&locals->RequiredPrefetchPixelDataBWLuma[i][j][k],
+			&locals->RequiredPrefetchPixelDataBWChroma[i][j][k],
+			&locals->VStartupRequiredWhenNotEnoughTimeForDynamicMetadata,
+			&locals->Tno_bw[k],
+			&locals->prefetch_vmrow_bw[k],
+			locals->swath_width_luma_ub,
+			locals->swath_width_chroma_ub,
+			&mode_lib->vba.VUpdateOffsetPix[k],
+			&mode_lib->vba.VUpdateWidthPix[k],
+			&mode_lib->vba.VReadyOffsetPix[k]);
+}
 void dml21_ModeSupportAndSystemConfigurationFull(struct display_mode_lib *mode_lib)
 {
 	struct vba_vars_st *locals = &mode_lib->vba;
@@ -4676,120 +4797,9 @@ void dml21_ModeSupportAndSystemConfigurationFull(struct display_mode_lib *mode_l
 						mode_lib->vba.DRAMClockChangeLatency,
 						mode_lib->vba.UrgentLatency,
 						mode_lib->vba.SREnterPlusExitTime);
-				for (k = 0; k <= mode_lib->vba.NumberOfActivePlanes - 1; k++) {
-					Pipe myPipe;
-					HostVM myHostVM;
-
-					if (mode_lib->vba.XFCEnabled[k] == true) {
-						mode_lib->vba.XFCRemoteSurfaceFlipDelay =
-								CalculateRemoteSurfaceFlipDelay(
-										mode_lib,
-										mode_lib->vba.VRatio[k],
-										locals->SwathWidthYThisState[k],
-										dml_ceil(locals->BytePerPixelInDETY[k], 1.0),
-										mode_lib->vba.HTotal[k] / mode_lib->vba.PixelClock[k],
-										mode_lib->vba.XFCTSlvVupdateOffset,
-										mode_lib->vba.XFCTSlvVupdateWidth,
-										mode_lib->vba.XFCTSlvVreadyOffset,
-										mode_lib->vba.XFCXBUFLatencyTolerance,
-										mode_lib->vba.XFCFillBWOverhead,
-										mode_lib->vba.XFCSlvChunkSize,
-										mode_lib->vba.XFCBusTransportTime,
-										mode_lib->vba.TimeCalc,
-										mode_lib->vba.TWait,
-										&mode_lib->vba.SrcActiveDrainRate,
-										&mode_lib->vba.TInitXFill,
-										&mode_lib->vba.TslvChk);
-					} else {
-						mode_lib->vba.XFCRemoteSurfaceFlipDelay = 0.0;
-					}
+				for (k = 0; k <= mode_lib->vba.NumberOfActivePlanes - 1; k++)
+					CalculatePrefetchSchedulePerPlane(mode_lib, i, j, k);
 
-					myPipe.DPPCLK = locals->RequiredDPPCLK[i][j][k];
-					myPipe.DISPCLK = locals->RequiredDISPCLK[i][j];
-					myPipe.PixelClock = mode_lib->vba.PixelClock[k];
-					myPipe.DCFCLKDeepSleep = mode_lib->vba.ProjectedDCFCLKDeepSleep[0][0];
-					myPipe.DPPPerPlane = locals->NoOfDPP[i][j][k];
-					myPipe.ScalerEnabled = mode_lib->vba.ScalerEnabled[k];
-					myPipe.SourceScan = mode_lib->vba.SourceScan[k];
-					myPipe.BlockWidth256BytesY = locals->Read256BlockWidthY[k];
-					myPipe.BlockHeight256BytesY = locals->Read256BlockHeightY[k];
-					myPipe.BlockWidth256BytesC = locals->Read256BlockWidthC[k];
-					myPipe.BlockHeight256BytesC = locals->Read256BlockHeightC[k];
-					myPipe.InterlaceEnable = mode_lib->vba.Interlace[k];
-					myPipe.NumberOfCursors = mode_lib->vba.NumberOfCursors[k];
-					myPipe.VBlank = mode_lib->vba.VTotal[k] - mode_lib->vba.VActive[k];
-					myPipe.HTotal = mode_lib->vba.HTotal[k];
-
-
-					myHostVM.Enable = mode_lib->vba.HostVMEnable;
-					myHostVM.MaxPageTableLevels = mode_lib->vba.HostVMMaxPageTableLevels;
-					myHostVM.CachedPageTableLevels = mode_lib->vba.HostVMCachedPageTableLevels;
-
-
-					mode_lib->vba.IsErrorResult[i][j][k] = CalculatePrefetchSchedule(
-							mode_lib,
-							mode_lib->vba.PercentOfIdealDRAMFabricAndSDPPortBWReceivedAfterUrgLatencyPixelMixedWithVMData,
-							mode_lib->vba.PercentOfIdealDRAMFabricAndSDPPortBWReceivedAfterUrgLatencyVMDataOnly,
-							&myPipe,
-							locals->DSCDelayPerState[i][k],
-							mode_lib->vba.DPPCLKDelaySubtotal,
-							mode_lib->vba.DPPCLKDelaySCL,
-							mode_lib->vba.DPPCLKDelaySCLLBOnly,
-							mode_lib->vba.DPPCLKDelayCNVCFormater,
-							mode_lib->vba.DPPCLKDelayCNVCCursor,
-							mode_lib->vba.DISPCLKDelaySubtotal,
-							locals->SwathWidthYThisState[k] / mode_lib->vba.HRatio[k],
-							mode_lib->vba.OutputFormat[k],
-							mode_lib->vba.MaxInterDCNTileRepeaters,
-							dml_min(mode_lib->vba.MaxVStartup, locals->MaximumVStartup[0][0][k]),
-							locals->MaximumVStartup[0][0][k],
-							mode_lib->vba.GPUVMMaxPageTableLevels,
-							mode_lib->vba.GPUVMEnable,
-							&myHostVM,
-							mode_lib->vba.DynamicMetadataEnable[k],
-							mode_lib->vba.DynamicMetadataLinesBeforeActiveRequired[k],
-							mode_lib->vba.DynamicMetadataTransmittedBytes[k],
-							mode_lib->vba.DCCEnable[k],
-							mode_lib->vba.UrgentLatency,
-							mode_lib->vba.ExtraLatency,
-							mode_lib->vba.TimeCalc,
-							locals->PDEAndMetaPTEBytesPerFrame[0][0][k],
-							locals->MetaRowBytes[0][0][k],
-							locals->DPTEBytesPerRow[0][0][k],
-							locals->PrefetchLinesY[0][0][k],
-							locals->SwathWidthYThisState[k],
-							locals->BytePerPixelInDETY[k],
-							locals->PrefillY[k],
-							locals->MaxNumSwY[k],
-							locals->PrefetchLinesC[0][0][k],
-							locals->BytePerPixelInDETC[k],
-							locals->PrefillC[k],
-							locals->MaxNumSwC[k],
-							locals->SwathHeightYThisState[k],
-							locals->SwathHeightCThisState[k],
-							mode_lib->vba.TWait,
-							mode_lib->vba.XFCEnabled[k],
-							mode_lib->vba.XFCRemoteSurfaceFlipDelay,
-							mode_lib->vba.ProgressiveToInterlaceUnitInOPP,
-							&locals->dst_x_after_scaler,
-							&locals->dst_y_after_scaler,
-							&locals->LineTimesForPrefetch[k],
-							&locals->PrefetchBW[k],
-							&locals->LinesForMetaPTE[k],
-							&locals->LinesForMetaAndDPTERow[k],
-							&locals->VRatioPreY[i][j][k],
-							&locals->VRatioPreC[i][j][k],
-							&locals->RequiredPrefetchPixelDataBWLuma[i][j][k],
-							&locals->RequiredPrefetchPixelDataBWChroma[i][j][k],
-							&locals->VStartupRequiredWhenNotEnoughTimeForDynamicMetadata,
-							&locals->Tno_bw[k],
-							&locals->prefetch_vmrow_bw[k],
-							locals->swath_width_luma_ub,
-							locals->swath_width_chroma_ub,
-							&mode_lib->vba.VUpdateOffsetPix[k],
-							&mode_lib->vba.VUpdateWidthPix[k],
-							&mode_lib->vba.VReadyOffsetPix[k]);
-				}
 				mode_lib->vba.MaximumReadBandwidthWithoutPrefetch = 0.0;
 				mode_lib->vba.MaximumReadBandwidthWithPrefetch = 0.0;
 				for (k = 0; k <= mode_lib->vba.NumberOfActivePlanes - 1; k++) {
-- 
2.33.0