Re: [PATCH 1/2] drm/i915: drop -Wall and related disables from cflags as redundant

[Nathan Chancellor <nathan@kernel.org>]

On Sun, Oct 08, 2023 at 12:28:46AM +0900, Masahiro Yamada wrote:
> On Fri, Oct 6, 2023 at 9:35 PM Jani Nikula <jani.nikula@intel.com> wrote:
> >
> > The kernel top level Makefile, and recently scripts/Makefile.extrawarn,
> > have included -Wall, and the disables -Wno-format-security and
> > $(call cc-disable-warning,frame-address,) for a very long time. They're
> > redundant in our local subdir-ccflags-y and can be dropped.
> >
> > Cc: Arnd Bergmann <arnd@arndb.de>
> > Cc: Nick Desaulniers <ndesaulniers@google.com>
> > Cc: Nathan Chancellor <nathan@kernel.org>
> > Cc: Masahiro Yamada <masahiroy@kernel.org>
> > Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> 
> 
> I made a similar suggestion in the past
> https://lore.kernel.org/dri-devel/20190515043753.9853-1-yamada.masahiro@socionext.com/
> 
> So, I am glad that Intel has decided to de-duplicate the flags.
> 
> 
> 
> I think you can drop more flags.
> 
> For example,
> 
>  subdir-ccflags-y += -Wno-sign-compare
> 
> 
> It is set by scripts/Makefile.extrawarn
> unless W=3 is passed.
> 
> 
> If W=3 is set by a user, -Wsign-compare should be warned
> as it is the user's request.
> 
> 
> drivers/gpu/drm/i915/Makefile negates W=3.
> There is no good reason to do so.
> 
> 
> Same applied to
> 
> 
> subdir-ccflags-y += -Wno-shift-negative-value

As I point out in my review of the second patch [1], I am not sure these
should be dropped because -Wextra turns these warnings back on, at least
for clang according to this build report [2] and my own testing, so they
need to be disabled again.

[1]: https://lore.kernel.org/20231006174550.GC3359308@dev-arch.thelio-3990X/
[2]: https://lore.kernel.org/202310070011.Fji48IBk-lkp@intel.com/

Cheers,
Nathan.