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* [PATCH] drm/i915: Disable -Wuninitialized for intel_breadcrumbs.o
@ 2018-10-25 19:36 Nathan Chancellor
  2018-10-25 22:20 ` Nick Desaulniers
  2018-12-17 17:41 ` Nathan Chancellor
  0 siblings, 2 replies; 6+ messages in thread
From: Nathan Chancellor @ 2018-10-25 19:36 UTC (permalink / raw)
  To: Jani Nikula, Joonas Lahtinen, Rodrigo Vivi
  Cc: intel-gfx, dri-devel, linux-kernel, Nick Desaulniers, Nathan Chancellor

This warning is disabled by default in scripts/Makefile.extrawarn when
W= is not provided but this Makefile adds -Wall after this warning is
disabled so it shows up in the build when it shouldn't:

In file included from drivers/gpu/drm/i915/intel_breadcrumbs.c:895:
drivers/gpu/drm/i915/selftests/intel_breadcrumbs.c:350:34: error:
variable 'wq' is uninitialized when used within its own initialization
[-Werror,-Wuninitialized]
        DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
                                        ^~
./include/linux/wait.h:74:63: note: expanded from macro
'DECLARE_WAIT_QUEUE_HEAD_ONSTACK'
        struct wait_queue_head name = __WAIT_QUEUE_HEAD_INIT_ONSTACK(name)
                               ~~~~                                  ^~~~
./include/linux/wait.h:72:33: note: expanded from macro
'__WAIT_QUEUE_HEAD_INIT_ONSTACK'
        ({ init_waitqueue_head(&name); name; })
                                       ^~~~
1 error generated.

This warning looks to be a false positive given that init_waitqueue_head
initializes name before it is used. Rather than disable the warning for
the full folder like commit 46e2068081e9 ("drm/i915: Disable some extra
clang warnings"), just disable it for the one problematic file because
it could be a useful warning for other cases.

Link: https://github.com/ClangBuiltLinux/linux/issues/220
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---
 drivers/gpu/drm/i915/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 1c2857f13ad4..f36c420afb99 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -26,6 +26,7 @@ subdir-ccflags-$(CONFIG_DRM_I915_WERROR) += -Werror
 
 # Fine grained warnings disable
 CFLAGS_i915_pci.o = $(call cc-disable-warning, override-init)
+CFLAGS_intel_breadcrumbs.o = $(call cc-disable-warning, uninitialized)
 CFLAGS_intel_fbdev.o = $(call cc-disable-warning, override-init)
 
 subdir-ccflags-y += \
-- 
2.19.1


^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2018-12-18 19:44 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-10-25 19:36 [PATCH] drm/i915: Disable -Wuninitialized for intel_breadcrumbs.o Nathan Chancellor
2018-10-25 22:20 ` Nick Desaulniers
2018-12-18 11:53   ` Chris Wilson
2018-12-18 19:01     ` Nathan Chancellor
2018-12-18 19:43       ` Nick Desaulniers
2018-12-17 17:41 ` Nathan Chancellor

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