[PATCH 0/5] drm/amd/display: Reduce stack usage for clang

[Nathan Chancellor <nathan@kernel.org>]

Hi all,

This series aims to address the following warnings, which are visible
when building x86_64 allmodconfig with clang after commit 3876a8b5e241
("drm/amd/display: Enable building new display engine with KCOV
enabled").

    drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn30/display_mode_vba_30.c:3542:6: error: stack frame size (2200) exceeds limit (2048) in 'dml30_ModeSupportAndSystemConfigurationFull' [-Werror,-Wframe-larger-than]
    void dml30_ModeSupportAndSystemConfigurationFull(struct display_mode_lib *mode_lib)
        ^
    1 error generated.

    drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn31/display_mode_vba_31.c:3908:6: error: stack frame size (2216) exceeds limit (2048) in 'dml31_ModeSupportAndSystemConfigurationFull' [-Werror,-Wframe-larger-than]
    void dml31_ModeSupportAndSystemConfigurationFull(struct display_mode_lib *mode_lib)
        ^
    1 error generated.

    drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn32/display_mode_vba_32.c:1721:6: error: stack frame size (2152) exceeds limit (2048) in 'dml32_ModeSupportAndSystemConfigurationFull' [-Werror,-Wframe-larger-than]
    void dml32_ModeSupportAndSystemConfigurationFull(struct display_mode_lib *mode_lib)
        ^
    1 error generated.

This series is based on commit b3235e8635e1 ("drm/amd/display: clean up
some inconsistent indentings"). These warnings are fatal for
allmodconfig due to CONFIG_WERROR so ideally, I would like to see these
patches cherry-picked to a branch targeting mainline to allow our builds
to go back to green. However, since this series is not exactly trivial
in size, I can understand not wanting to apply these to mainline during
the -rc cycle. If they cannot be cherry-picked to mainline, I can add a
patch raising the value of -Wframe-larger-than for these files that can
be cherry-picked to 6.0/mainline then add a revert of that change as the
last patch in the stack so everything goes back to normal for -next/6.1.
I am open to other options though!

I have built this series against clang 16.0.0 (ToT) and GCC 12.2.0 for
x86_64. It has seen no runtime testing, as my only test system with AMD
graphics is a Renoir one, which as far as I understand it uses DCN 2.1.

Nathan Chancellor (5):
  drm/amd/display: Reduce number of arguments of
    dml32_CalculateWatermarksMALLUseAndDRAMSpeedChangeSupport()
  drm/amd/display: Reduce number of arguments of
    dml32_CalculatePrefetchSchedule()
  drm/amd/display: Reduce number of arguments of dml31's
    CalculateWatermarksAndDRAMSpeedChangeSupport()
  drm/amd/display: Reduce number of arguments of dml31's
    CalculateFlipSchedule()
  drm/amd/display: Mark dml30's UseMinimumDCFCLK() as noinline for stack
    usage

 .../dc/dml/dcn30/display_mode_vba_30.c        |   2 +-
 .../dc/dml/dcn31/display_mode_vba_31.c        | 420 +++++-------------
 .../dc/dml/dcn32/display_mode_vba_32.c        | 236 +++-------
 .../dc/dml/dcn32/display_mode_vba_util_32.c   | 323 ++++++--------
 .../dc/dml/dcn32/display_mode_vba_util_32.h   |  51 +--
 5 files changed, 318 insertions(+), 714 deletions(-)


base-commit: b3235e8635e1dd7ac1a27a73330e9880dfe05154
-- 
2.37.2