Re: [PATCH] drm/amdgpu: Mark mmhub_v1_8_mmea_err_status_reg as __maybe_unused

From: Alex Deucher <alexdeucher@gmail.com>
To: Nathan Chancellor <nathan@kernel.org>
Cc: "Luben Tuikov" <luben.tuikov@amd.com>,
	"Lijo Lazar" <lijo.lazar@amd.com>,
	"Srinivasan Shanmugam" <srinivasan.shanmugam@amd.com>,
	llvm@lists.linux.dev, amd-gfx@lists.freedesktop.org,
	"Alex Deucher" <alexander.deucher@amd.com>,
	"Christian König" <christian.koenig@amd.com>
Subject: Re: [PATCH] drm/amdgpu: Mark mmhub_v1_8_mmea_err_status_reg as __maybe_unused
Date: Thu, 25 May 2023 12:42:05 -0400	[thread overview]
Message-ID: <CADnq5_Ndax1krkonfeBt4=iW5Kfh-nW+M_UhqVJV9gUQC2JEBw@mail.gmail.com> (raw)
In-Reply-To: <20230525162911.GA552113@dev-arch.thelio-3990X>

On Thu, May 25, 2023 at 12:29 PM Nathan Chancellor <nathan@kernel.org> wrote:
>
> On Thu, May 25, 2023 at 12:26:56PM -0400, Luben Tuikov wrote:
> > On 2023-05-25 11:22, Nathan Chancellor wrote:
> > > On Fri, May 19, 2023 at 06:14:38PM +0530, Srinivasan Shanmugam wrote:
> > >> Silencing the compiler from below compilation error:
> > >>
> > >> drivers/gpu/drm/amd/amdgpu/mmhub_v1_8.c:704:23: error: variable 'mmhub_v1_8_mmea_err_status_reg' is not needed and will not be emitted [-Werror,-Wunneeded-internal-declaration]
> > >> static const uint32_t mmhub_v1_8_mmea_err_status_reg[] = {
> > >>                       ^
> > >> 1 error generated.
> > >>
> > >> Mark the variable as __maybe_unused to make it clear to clang that this
> > >> is expected, so there is no more warning.
> > >>
> > >> Cc: Christian König <christian.koenig@amd.com>
> > >> Cc: Lijo Lazar <lijo.lazar@amd.com>
> > >> Cc: Luben Tuikov <luben.tuikov@amd.com>
> > >> Cc: Alex Deucher <alexander.deucher@amd.com>
> > >> Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
> > >
> > > Traditionally, this attribute would go between the [] and =, but that is
> > > a nit. Can someone please pick this up to unblock our builds on -next?
> > >
> > > Reviewed-by: Nathan Chancellor <nathan@kernel.org>
> >
> > I'll pick this up, fix it, and submit to amd-staging-drm-next.
>
> Thanks a lot :)
>
> > Which -next are you referring to, Nathan?
>
> linux-next, this warning breaks the build when -Werror is enabled, such
> as with allmodconfig:
>
> https://storage.tuxsuite.com/public/clangbuiltlinux/continuous-integration2/builds/2QHtlCTz2JL0yXNpRB5hVmiP9lq/build.log
>

Srinivasan has already pushed it.  I'll push it out once CI has
completed.  We are trying to figure out the best way to enable -WERROR
in our CI system as it is almost always broken depending on what
compiler you are using.  Also, I'm not sure fixing these is always
better.  A lot of these warnings seem spurious and in a lot of cases
the "fix" doesn't really improve the code, it just silences a warning.
As one of my coworkers put it, there is a reason warnings are not
errors.

Alex

> Cheers,
> Nathan
>
> > >> ---
> > >>  drivers/gpu/drm/amd/amdgpu/mmhub_v1_8.c | 1 +
> > >>  1 file changed, 1 insertion(+)
> > >>
> > >> diff --git a/drivers/gpu/drm/amd/amdgpu/mmhub_v1_8.c b/drivers/gpu/drm/amd/amdgpu/mmhub_v1_8.c
> > >> index 3648994724c2..cba087e529c0 100644
> > >> --- a/drivers/gpu/drm/amd/amdgpu/mmhub_v1_8.c
> > >> +++ b/drivers/gpu/drm/amd/amdgpu/mmhub_v1_8.c
> > >> @@ -701,6 +701,7 @@ static void mmhub_v1_8_reset_ras_error_count(struct amdgpu_device *adev)
> > >>            mmhub_v1_8_inst_reset_ras_error_count(adev, i);
> > >>  }
> > >>
> > >> +__maybe_unused
> > >>  static const uint32_t mmhub_v1_8_mmea_err_status_reg[] = {
> > >>    regMMEA0_ERR_STATUS,
> > >>    regMMEA1_ERR_STATUS,
> > >> --
> > >> 2.25.1
> > >>
> >