Re: [PATCH 4/6] drm/amd/display: Refactor dml_core_mode_support to reduce stack frame

Tue, 02 Dec 2025 08:31:35 -0800 



On 12/2/25 09:29, Alex Hung wrote:



On 12/2/25 03:21, Chenyu Chen wrote:

From: Alex Hung <[email protected]>

[WHAT]
When compiling Linux kernel with clang, the following warning / error
messages pops up:


drivers/gpu/drm/amd/amdgpu/../dal-dev/dc/dml2_0/ 
display_mode_core.c:6853:12:

error: stack frame size (2120) exceeds limit (2056) in
'dml_core_mode_support' [-Werror,-Wframe-larger-than]
  6853 | dml_bool_t dml_core_mode_support(struct display_mode_lib_st
*mode_lib)

[HOW]
Refactoring CalculateVMRowAndSwath_params assignments to a new function
helps reduce the stack frame size in dml_core_mode_support.


Hi Chenyu,

A bug seems to be related. Can you add a buglink? Thanks.

Buglink: https://gitlab.freedesktop.org/drm/amd/-/issues/4733


Correction, Add "Closes" instead of "Buglink"




Reviewed-by: Austin Zheng <[email protected]>
Reviewed-by: Aurabindo Pillai <[email protected]>
Signed-off-by: Alex Hung <[email protected]>
Signed-off-by: Chenyu Chen <[email protected]>
---
  .../amd/display/dc/dml2_0/display_mode_core.c | 134 ++++++++++--------
  1 file changed, 71 insertions(+), 63 deletions(-)


diff --git a/drivers/gpu/drm/amd/display/dc/dml2_0/display_mode_core.c 
b/drivers/gpu/drm/amd/display/dc/dml2_0/display_mode_core.c

index c468f492b876..09303c282495 100644
--- a/drivers/gpu/drm/amd/display/dc/dml2_0/display_mode_core.c
+++ b/drivers/gpu/drm/amd/display/dc/dml2_0/display_mode_core.c

@@ -6711,6 +6711,76 @@ static noinline_for_stack void 
dml_prefetch_check(struct display_mode_lib_st *mo

      } // for j
  }

+static noinline_for_stack void set_vm_row_and_swath_parameters(struct 
display_mode_lib_st *mode_lib)

+{

+    struct CalculateVMRowAndSwath_params_st 
*CalculateVMRowAndSwath_params = &mode_lib- 
>scratch.CalculateVMRowAndSwath_params;
+    struct dml_core_mode_support_locals_st *s = &mode_lib- 
>scratch.dml_core_mode_support_locals;

+

+    CalculateVMRowAndSwath_params->NumberOfActiveSurfaces = mode_lib- 
>ms.num_active_planes;

+    CalculateVMRowAndSwath_params->myPipe = s->SurfParameters;

+    CalculateVMRowAndSwath_params->SurfaceSizeInMALL = mode_lib- 
>ms.SurfaceSizeInMALL;
+    CalculateVMRowAndSwath_params->PTEBufferSizeInRequestsLuma = 
mode_lib->ms.ip.dpte_buffer_size_in_pte_reqs_luma;
+    CalculateVMRowAndSwath_params->PTEBufferSizeInRequestsChroma = 
mode_lib->ms.ip.dpte_buffer_size_in_pte_reqs_chroma;
+    CalculateVMRowAndSwath_params->DCCMetaBufferSizeBytes = mode_lib- 
>ms.ip.dcc_meta_buffer_size_bytes;
+    CalculateVMRowAndSwath_params->UseMALLForStaticScreen = mode_lib- 
>ms.cache_display_cfg.plane.UseMALLForStaticScreen;
+    CalculateVMRowAndSwath_params->UseMALLForPStateChange = mode_lib- 
>ms.cache_display_cfg.plane.UseMALLForPStateChange;
+    CalculateVMRowAndSwath_params->MALLAllocatedForDCN = mode_lib- 
>ms.soc.mall_allocated_for_dcn_mbytes;
+    CalculateVMRowAndSwath_params->SwathWidthY = mode_lib- 
>ms.SwathWidthYThisState;
+    CalculateVMRowAndSwath_params->SwathWidthC = mode_lib- 
>ms.SwathWidthCThisState;
+    CalculateVMRowAndSwath_params->GPUVMEnable = mode_lib- 
>ms.cache_display_cfg.plane.GPUVMEnable;
+    CalculateVMRowAndSwath_params->HostVMEnable = mode_lib- 
>ms.cache_display_cfg.plane.HostVMEnable;
+    CalculateVMRowAndSwath_params->HostVMMaxNonCachedPageTableLevels 
= mode_lib->ms.cache_display_cfg.plane.HostVMMaxPageTableLevels;
+    CalculateVMRowAndSwath_params->GPUVMMaxPageTableLevels = 
mode_lib->ms.cache_display_cfg.plane.GPUVMMaxPageTableLevels;
+    CalculateVMRowAndSwath_params->GPUVMMinPageSizeKBytes = mode_lib- 
>ms.cache_display_cfg.plane.GPUVMMinPageSizeKBytes;
+    CalculateVMRowAndSwath_params->HostVMMinPageSize = mode_lib- 
>ms.soc.hostvm_min_page_size_kbytes * 1024;
+    CalculateVMRowAndSwath_params->PTEBufferModeOverrideEn = 
mode_lib->ms.cache_display_cfg.plane.PTEBufferModeOverrideEn;
+    CalculateVMRowAndSwath_params->PTEBufferModeOverrideVal = 
mode_lib->ms.cache_display_cfg.plane.PTEBufferMode;
+    CalculateVMRowAndSwath_params->PTEBufferSizeNotExceeded = 
mode_lib->ms.PTEBufferSizeNotExceededPerState;
+    CalculateVMRowAndSwath_params->DCCMetaBufferSizeNotExceeded = 
mode_lib->ms.DCCMetaBufferSizeNotExceededPerState;
+    CalculateVMRowAndSwath_params->dpte_row_width_luma_ub = s- 
>dummy_integer_array[0];
+    CalculateVMRowAndSwath_params->dpte_row_width_chroma_ub = s- 
>dummy_integer_array[1];
+    CalculateVMRowAndSwath_params->dpte_row_height_luma = mode_lib- 
>ms.dpte_row_height;
+    CalculateVMRowAndSwath_params->dpte_row_height_chroma = mode_lib- 
>ms.dpte_row_height_chroma;
+    CalculateVMRowAndSwath_params->dpte_row_height_linear_luma = s- 
>dummy_integer_array[2]; // VBA_DELTA
+    CalculateVMRowAndSwath_params->dpte_row_height_linear_chroma = s- 
>dummy_integer_array[3]; // VBA_DELTA
+    CalculateVMRowAndSwath_params->meta_req_width = s- 
>dummy_integer_array[4];
+    CalculateVMRowAndSwath_params->meta_req_width_chroma = s- 
>dummy_integer_array[5];
+    CalculateVMRowAndSwath_params->meta_req_height = s- 
>dummy_integer_array[6];
+    CalculateVMRowAndSwath_params->meta_req_height_chroma = s- 
>dummy_integer_array[7];
+    CalculateVMRowAndSwath_params->meta_row_width = s- 
>dummy_integer_array[8];
+    CalculateVMRowAndSwath_params->meta_row_width_chroma = s- 
>dummy_integer_array[9];
+    CalculateVMRowAndSwath_params->meta_row_height = mode_lib- 
>ms.meta_row_height;
+    CalculateVMRowAndSwath_params->meta_row_height_chroma = mode_lib- 
>ms.meta_row_height_chroma;
+    CalculateVMRowAndSwath_params->vm_group_bytes = s- 
>dummy_integer_array[10];
+    CalculateVMRowAndSwath_params->dpte_group_bytes = mode_lib- 
>ms.dpte_group_bytes;
+    CalculateVMRowAndSwath_params->PixelPTEReqWidthY = s- 
>dummy_integer_array[11];
+    CalculateVMRowAndSwath_params->PixelPTEReqHeightY = s- 
>dummy_integer_array[12];
+    CalculateVMRowAndSwath_params->PTERequestSizeY = s- 
>dummy_integer_array[13];
+    CalculateVMRowAndSwath_params->PixelPTEReqWidthC = s- 
>dummy_integer_array[14];
+    CalculateVMRowAndSwath_params->PixelPTEReqHeightC = s- 
>dummy_integer_array[15];
+    CalculateVMRowAndSwath_params->PTERequestSizeC = s- 
>dummy_integer_array[16];
+    CalculateVMRowAndSwath_params->dpde0_bytes_per_frame_ub_l = s- 
>dummy_integer_array[17];
+    CalculateVMRowAndSwath_params->meta_pte_bytes_per_frame_ub_l = s- 
>dummy_integer_array[18];
+    CalculateVMRowAndSwath_params->dpde0_bytes_per_frame_ub_c = s- 
>dummy_integer_array[19];
+    CalculateVMRowAndSwath_params->meta_pte_bytes_per_frame_ub_c = s- 
>dummy_integer_array[20];
+    CalculateVMRowAndSwath_params->PrefetchSourceLinesY = mode_lib- 
>ms.PrefetchLinesYThisState;
+    CalculateVMRowAndSwath_params->PrefetchSourceLinesC = mode_lib- 
>ms.PrefetchLinesCThisState;
+    CalculateVMRowAndSwath_params->VInitPreFillY = mode_lib- 
>ms.PrefillY;
+    CalculateVMRowAndSwath_params->VInitPreFillC = mode_lib- 
>ms.PrefillC;
+    CalculateVMRowAndSwath_params->MaxNumSwathY = mode_lib- 
>ms.MaxNumSwY;
+    CalculateVMRowAndSwath_params->MaxNumSwathC = mode_lib- 
>ms.MaxNumSwC;
+    CalculateVMRowAndSwath_params->meta_row_bw = mode_lib- 
>ms.meta_row_bandwidth_this_state;
+    CalculateVMRowAndSwath_params->dpte_row_bw = mode_lib- 
>ms.dpte_row_bandwidth_this_state;
+    CalculateVMRowAndSwath_params->PixelPTEBytesPerRow = mode_lib- 
>ms.DPTEBytesPerRowThisState;
+    CalculateVMRowAndSwath_params->PDEAndMetaPTEBytesFrame = 
mode_lib->ms.PDEAndMetaPTEBytesPerFrameThisState;
+    CalculateVMRowAndSwath_params->MetaRowByte = mode_lib- 
>ms.MetaRowBytesThisState;
+    CalculateVMRowAndSwath_params->use_one_row_for_frame = mode_lib- 
>ms.use_one_row_for_frame_this_state;
+    CalculateVMRowAndSwath_params->use_one_row_for_frame_flip = 
mode_lib->ms.use_one_row_for_frame_flip_this_state;
+    CalculateVMRowAndSwath_params->UsesMALLForStaticScreen = s- 
>dummy_boolean_array[0];
+    CalculateVMRowAndSwath_params->PTE_BUFFER_MODE = s- 
>dummy_boolean_array[1];
+    CalculateVMRowAndSwath_params->BIGK_FRAGMENT_SIZE = s- 
>dummy_integer_array[21];

+}
+
  /// @brief The Mode Support function.
  dml_bool_t dml_core_mode_support(struct display_mode_lib_st *mode_lib)
  {

@@ -7683,69 +7753,7 @@ dml_bool_t dml_core_mode_support(struct 
display_mode_lib_st *mode_lib)
              s->SurfParameters[k].SwathHeightC = mode_lib- 
>ms.SwathHeightCThisState[k];

          }

-        CalculateVMRowAndSwath_params->NumberOfActiveSurfaces = 
mode_lib->ms.num_active_planes;

-        CalculateVMRowAndSwath_params->myPipe = s->SurfParameters;

-        CalculateVMRowAndSwath_params->SurfaceSizeInMALL = mode_lib- 
>ms.SurfaceSizeInMALL;
-        CalculateVMRowAndSwath_params->PTEBufferSizeInRequestsLuma = 
mode_lib->ms.ip.dpte_buffer_size_in_pte_reqs_luma;
-        CalculateVMRowAndSwath_params->PTEBufferSizeInRequestsChroma 
= mode_lib->ms.ip.dpte_buffer_size_in_pte_reqs_chroma;
-        CalculateVMRowAndSwath_params->DCCMetaBufferSizeBytes = 
mode_lib->ms.ip.dcc_meta_buffer_size_bytes;
-        CalculateVMRowAndSwath_params->UseMALLForStaticScreen = 
mode_lib->ms.cache_display_cfg.plane.UseMALLForStaticScreen;
-        CalculateVMRowAndSwath_params->UseMALLForPStateChange = 
mode_lib->ms.cache_display_cfg.plane.UseMALLForPStateChange;
-        CalculateVMRowAndSwath_params->MALLAllocatedForDCN = 
mode_lib->ms.soc.mall_allocated_for_dcn_mbytes;
-        CalculateVMRowAndSwath_params->SwathWidthY = mode_lib- 
>ms.SwathWidthYThisState;
-        CalculateVMRowAndSwath_params->SwathWidthC = mode_lib- 
>ms.SwathWidthCThisState;
-        CalculateVMRowAndSwath_params->GPUVMEnable = mode_lib- 
>ms.cache_display_cfg.plane.GPUVMEnable;
-        CalculateVMRowAndSwath_params->HostVMEnable = mode_lib- 
>ms.cache_display_cfg.plane.HostVMEnable;
-        CalculateVMRowAndSwath_params- 
>HostVMMaxNonCachedPageTableLevels = mode_lib- 
>ms.cache_display_cfg.plane.HostVMMaxPageTableLevels;
-        CalculateVMRowAndSwath_params->GPUVMMaxPageTableLevels = 
mode_lib->ms.cache_display_cfg.plane.GPUVMMaxPageTableLevels;
-        CalculateVMRowAndSwath_params->GPUVMMinPageSizeKBytes = 
mode_lib->ms.cache_display_cfg.plane.GPUVMMinPageSizeKBytes;
-        CalculateVMRowAndSwath_params->HostVMMinPageSize = mode_lib- 
>ms.soc.hostvm_min_page_size_kbytes * 1024;
-        CalculateVMRowAndSwath_params->PTEBufferModeOverrideEn = 
mode_lib->ms.cache_display_cfg.plane.PTEBufferModeOverrideEn;
-        CalculateVMRowAndSwath_params->PTEBufferModeOverrideVal = 
mode_lib->ms.cache_display_cfg.plane.PTEBufferMode;
-        CalculateVMRowAndSwath_params->PTEBufferSizeNotExceeded = 
mode_lib->ms.PTEBufferSizeNotExceededPerState;
-        CalculateVMRowAndSwath_params->DCCMetaBufferSizeNotExceeded = 
mode_lib->ms.DCCMetaBufferSizeNotExceededPerState;
-        CalculateVMRowAndSwath_params->dpte_row_width_luma_ub = s- 
>dummy_integer_array[0];
-        CalculateVMRowAndSwath_params->dpte_row_width_chroma_ub = s- 
>dummy_integer_array[1];
-        CalculateVMRowAndSwath_params->dpte_row_height_luma = 
mode_lib->ms.dpte_row_height;
-        CalculateVMRowAndSwath_params->dpte_row_height_chroma = 
mode_lib->ms.dpte_row_height_chroma;
-        CalculateVMRowAndSwath_params->dpte_row_height_linear_luma = 
s->dummy_integer_array[2]; // VBA_DELTA
-        CalculateVMRowAndSwath_params->dpte_row_height_linear_chroma 
= s->dummy_integer_array[3]; // VBA_DELTA
-        CalculateVMRowAndSwath_params->meta_req_width = s- 
>dummy_integer_array[4];
-        CalculateVMRowAndSwath_params->meta_req_width_chroma = s- 
>dummy_integer_array[5];
-        CalculateVMRowAndSwath_params->meta_req_height = s- 
>dummy_integer_array[6];
-        CalculateVMRowAndSwath_params->meta_req_height_chroma = s- 
>dummy_integer_array[7];
-        CalculateVMRowAndSwath_params->meta_row_width = s- 
>dummy_integer_array[8];
-        CalculateVMRowAndSwath_params->meta_row_width_chroma = s- 
>dummy_integer_array[9];
-        CalculateVMRowAndSwath_params->meta_row_height = mode_lib- 
>ms.meta_row_height;
-        CalculateVMRowAndSwath_params->meta_row_height_chroma = 
mode_lib->ms.meta_row_height_chroma;
-        CalculateVMRowAndSwath_params->vm_group_bytes = s- 
>dummy_integer_array[10];
-        CalculateVMRowAndSwath_params->dpte_group_bytes = mode_lib- 
>ms.dpte_group_bytes;
-        CalculateVMRowAndSwath_params->PixelPTEReqWidthY = s- 
>dummy_integer_array[11];
-        CalculateVMRowAndSwath_params->PixelPTEReqHeightY = s- 
>dummy_integer_array[12];
-        CalculateVMRowAndSwath_params->PTERequestSizeY = s- 
>dummy_integer_array[13];
-        CalculateVMRowAndSwath_params->PixelPTEReqWidthC = s- 
>dummy_integer_array[14];
-        CalculateVMRowAndSwath_params->PixelPTEReqHeightC = s- 
>dummy_integer_array[15];
-        CalculateVMRowAndSwath_params->PTERequestSizeC = s- 
>dummy_integer_array[16];
-        CalculateVMRowAndSwath_params->dpde0_bytes_per_frame_ub_l = 
s->dummy_integer_array[17];
-        CalculateVMRowAndSwath_params->meta_pte_bytes_per_frame_ub_l 
= s->dummy_integer_array[18];
-        CalculateVMRowAndSwath_params->dpde0_bytes_per_frame_ub_c = 
s->dummy_integer_array[19];
-        CalculateVMRowAndSwath_params->meta_pte_bytes_per_frame_ub_c 
= s->dummy_integer_array[20];
-        CalculateVMRowAndSwath_params->PrefetchSourceLinesY = 
mode_lib->ms.PrefetchLinesYThisState;
-        CalculateVMRowAndSwath_params->PrefetchSourceLinesC = 
mode_lib->ms.PrefetchLinesCThisState;
-        CalculateVMRowAndSwath_params->VInitPreFillY = mode_lib- 
>ms.PrefillY;
-        CalculateVMRowAndSwath_params->VInitPreFillC = mode_lib- 
>ms.PrefillC;
-        CalculateVMRowAndSwath_params->MaxNumSwathY = mode_lib- 
>ms.MaxNumSwY;
-        CalculateVMRowAndSwath_params->MaxNumSwathC = mode_lib- 
>ms.MaxNumSwC;
-        CalculateVMRowAndSwath_params->meta_row_bw = mode_lib- 
>ms.meta_row_bandwidth_this_state;
-        CalculateVMRowAndSwath_params->dpte_row_bw = mode_lib- 
>ms.dpte_row_bandwidth_this_state;
-        CalculateVMRowAndSwath_params->PixelPTEBytesPerRow = 
mode_lib->ms.DPTEBytesPerRowThisState;
-        CalculateVMRowAndSwath_params->PDEAndMetaPTEBytesFrame = 
mode_lib->ms.PDEAndMetaPTEBytesPerFrameThisState;
-        CalculateVMRowAndSwath_params->MetaRowByte = mode_lib- 
>ms.MetaRowBytesThisState;
-        CalculateVMRowAndSwath_params->use_one_row_for_frame = 
mode_lib->ms.use_one_row_for_frame_this_state;
-        CalculateVMRowAndSwath_params->use_one_row_for_frame_flip = 
mode_lib->ms.use_one_row_for_frame_flip_this_state;
-        CalculateVMRowAndSwath_params->UsesMALLForStaticScreen = s- 
>dummy_boolean_array[0];
-        CalculateVMRowAndSwath_params->PTE_BUFFER_MODE = s- 
>dummy_boolean_array[1];
-        CalculateVMRowAndSwath_params->BIGK_FRAGMENT_SIZE = s- 
>dummy_integer_array[21];

+        set_vm_row_and_swath_parameters(mode_lib);
          CalculateVMRowAndSwath(&mode_lib->scratch,
              CalculateVMRowAndSwath_params);


























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