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-Wsometimes-uninitialized in drivers/gpu/drm/stm/ltdc.c #1575

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nathanchance opened this issue Feb 2, 2022 · 4 comments
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-Wsometimes-uninitialized in drivers/gpu/drm/stm/ltdc.c #1575

nathanchance opened this issue Feb 2, 2022 · 4 comments
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-Wsometimes-uninitialized [BUG] linux-next This is an issue only seen in linux-next [FIXED][LINUX] development cycle This bug was only present and fixed in a -next or -rc cycle

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drivers/gpu/drm/stm/ltdc.c:625:2: warning: variable 'val' is used uninitialized whenever switch default is taken [-Wsometimes-uninitialized]
        default:
        ^~~~~~~
drivers/gpu/drm/stm/ltdc.c:635:2: note: uninitialized use occurs here
        val |= LxPCR_YCEN;
        ^~~
drivers/gpu/drm/stm/ltdc.c:600:9: note: initialize the variable 'val' to silence this warning
        u32 val;
               ^
                = 0
1 warning generated.

Reported upstream: https://lore.kernel.org/r/Yfq3XwozrxYaFhgD@dev-arch.archlinux-ax161/
@nathanchance nathanchance added [BUG] linux-next This is an issue only seen in linux-next -Wsometimes-uninitialized Reported upstream This bug was filed on LLVM’s issue tracker, Phabricator, or the kernel mailing list. labels Feb 2, 2022
@nathanchance nathanchance self-assigned this Feb 2, 2022
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Patch submitted: https://lore.kernel.org/r/20220207165304.1046867-1-nathan@kernel.org/

@nathanchance nathanchance added [PATCH] Submitted A patch has been submitted for review and removed Reported upstream This bug was filed on LLVM’s issue tracker, Phabricator, or the kernel mailing list. labels Feb 7, 2022
fengguang pushed a commit to 0day-ci/linux that referenced this issue Feb 22, 2022
@nathanchance @intel-lab-lkp
drm/stm: Avoid using val uninitialized in ltdc_set_ycbcr_config()
47f0387 
Clang warns:

  drivers/gpu/drm/stm/ltdc.c:625:2: warning: variable 'val' is used uninitialized whenever switch default is taken [-Wsometimes-uninitialized]
          default:
          ^~~~~~~
  drivers/gpu/drm/stm/ltdc.c:635:2: note: uninitialized use occurs here
          val |= LxPCR_YCEN;
          ^~~
  drivers/gpu/drm/stm/ltdc.c:600:9: note: initialize the variable 'val' to silence this warning
          u32 val;
                 ^
                  = 0
  1 warning generated.

Use a return instead of break in the default case to fix the warning.
Add an error message so that this return is not silent, which could hide
issues in the future.

Fixes: 484e72d ("drm/stm: ltdc: add support of ycbcr pixel formats")
Link: ClangBuiltLinux#1575
Acked-by: Yannick Fertre <yannick.fertre@foss.st.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
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v2: https://lore.kernel.org/r/20220222152045.484610-1-nathan@kernel.org/

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Patch accepted: https://cgit.freedesktop.org/drm/drm-misc/commit/?id=3b2f68f196a5b23c61777078f5c7d0d19626b5e4

@nathanchance nathanchance added [PATCH] Accepted A submitted patch has been accepted upstream and removed [PATCH] Submitted A patch has been submitted for review labels Feb 25, 2022
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Patch is now available in next-20220307: https://git.kernel.org/next/linux-next/c/3b2f68f196a5b23c61777078f5c7d0d19626b5e4

@nathanchance nathanchance added [FIXED][LINUX] development cycle This bug was only present and fixed in a -next or -rc cycle and removed [PATCH] Accepted A submitted patch has been accepted upstream labels Mar 7, 2022
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