linux-kernel - Re: [PATCH] drm/amd/display: Increase frame-larger-than warning limit

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Date: Tue, 04 Jun 2024 09:04:23 -0700 (PDT)
From: Palmer Dabbelt <palmer@...osinc.com>
To: nathan@...nel.org
CC: alexander.deucher@....com, harry.wentland@....com, sunpeng.li@....com,
  Rodrigo.Siqueira@....com, christian.koenig@....com, Xinhui.Pan@....com, airlied@...il.com,
  daniel@...ll.ch, Qingqing.Zhuo@....com, hamza.mahfooz@....com, chenhuacai@...nel.org,
  amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject:     Re: [PATCH] drm/amd/display: Increase frame-larger-than warning limit

On Mon, 03 Jun 2024 15:29:48 PDT (-0700), nathan@...nel.org wrote:
> Hi Palmer,
>
> On Thu, May 30, 2024 at 07:57:42AM -0700, Palmer Dabbelt wrote:
>> From: Palmer Dabbelt <palmer@...osinc.com>
>>
>> I get a handful of build errors along the lines of
>>
>>     linux/drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn32/display_mode_vba_32.c:58:13: error: stack frame size (2352) exceeds limit (2048) in 'DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation' [-Werror,-Wframe-larger-than]
>>     static void DISPCLKDPPCLKDCFCLKDeepSleepPrefetchParametersWatermarksAndPerformanceCalculation(
>>                 ^
>>     linux/drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn32/display_mode_vba_32.c:1724:6: error: stack frame size (2096) exceeds limit (2048) in 'dml32_ModeSupportAndSystemConfigurationFull' [-Werror,-Wframe-larger-than]
>>     void dml32_ModeSupportAndSystemConfigurationFull(struct display_mode_lib *mode_lib)
>>          ^
>
> Judging from the message, this is clang/LLVM? What version?

Yes, LLVM.  Looks like I'm on 16.0.6.  Probably time for an update, so 
I'll give it a shot.

> I assume
> this showed up in 6.10-rc1 because of commit 77acc6b55ae4 ("riscv: add
> support for kernel-mode FPU"), which allows this driver to be built for
> RISC-V.

Seems reasonable.  This didn't show up until post-merge, not 100% sure 
why.  I didn't really dig any farther.

> Is this allmodconfig or some other configuration?

IIRC both "allmodconfig" and "allyesconfig" show it, but I don't have a 
build tree sitting around to be 100% sure.

>> as of 6.10-rc1.
>>
>> Signed-off-by: Palmer Dabbelt <palmer@...osinc.com>
>> ---
>>  drivers/gpu/drm/amd/display/dc/dml/Makefile | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/display/dc/dml/Makefile b/drivers/gpu/drm/amd/display/dc/dml/Makefile
>> index c4a5efd2dda5..b2bd72e63734 100644
>> --- a/drivers/gpu/drm/amd/display/dc/dml/Makefile
>> +++ b/drivers/gpu/drm/amd/display/dc/dml/Makefile
>> @@ -62,9 +62,9 @@ endif
>>
>>  ifneq ($(CONFIG_FRAME_WARN),0)
>>  ifeq ($(filter y,$(CONFIG_KASAN)$(CONFIG_KCSAN)),y)
>> -frame_warn_flag := -Wframe-larger-than=3072
>> +frame_warn_flag := -Wframe-larger-than=4096
>>  else
>> -frame_warn_flag := -Wframe-larger-than=2048
>> +frame_warn_flag := -Wframe-larger-than=3072
>>  endif
>>  endif
>>
>> --
>> 2.45.1
>>