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From: Zhouyi Zhou <zhouzhouyi@gmail.com>
Date: Tue, 28 May 2024 09:45:03 +0800
Message-ID: <CAABZP2ximP0kiSSXSw51fhrt0EuZMLUHeonzS2VGSUwm-QEF3w@mail.gmail.com>
Subject: Re: [PATCH] drm/radeon/r100: enhance error handling in r100_cp_init_microcode
To: =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>
Cc: alexander.deucher@amd.com, Xinhui.Pan@amd.com, airlied@gmail.com, 
	daniel@ffwll.ch, chris@chrisdown.name, amd-gfx@lists.freedesktop.org, 
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, 
	rcu@vger.kernel.org, lance@osuosl.org
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Fix some error in my previous email

On Tue, May 28, 2024 at 9:36=E2=80=AFAM Zhouyi Zhou <zhouzhouyi@gmail.com> =
wrote:
>
> Thanks for reviewing the patch
>
> On Mon, May 27, 2024 at 3:58=E2=80=AFPM Christian K=C3=B6nig
> <christian.koenig@amd.com> wrote:
> >
> > Am 27.05.24 um 03:20 schrieb Zhouyi Zhou:
> > > In r100_cp_init_microcode, if rdev->family don't match any of
> > > if statement,  fw_name will be NULL, which will cause
> > > gcc (11.4.0 powerpc64le-linux-gnu) complain:
> > >
> > > In function =E2=80=98r100_cp_init_microcode=E2=80=99,
> > >      inlined from =E2=80=98r100_cp_init=E2=80=99 at drivers/gpu/drm/r=
adeon/r100.c:1136:7:
> > > ./include/linux/printk.h:457:44: warning: =E2=80=98%s=E2=80=99 direct=
ive argument is null [-Wformat-overflow=3D]
> > >    457 | #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##_=
_VA_ARGS__)
> > >
> > > Above warning is emitted during the rcutorture test in
> > > in PPC VM of Opensource Lab of Oregon State Univerisity.
> > >
> > > Enhance error handling in r100_cp_init_microcode, let r100_cp_init_mi=
crocode
> > > return with -EINVAL when none of chip families is matched.
> > >
> > > Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
> >
> > > ---
> > >   drivers/gpu/drm/radeon/r100.c | 7 +++++++
> > >   1 file changed, 7 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/radeon/r100.c b/drivers/gpu/drm/radeon/r=
100.c
> > > index 0b1e19345f43..4f8a1bdd9365 100644
> > > --- a/drivers/gpu/drm/radeon/r100.c
> > > +++ b/drivers/gpu/drm/radeon/r100.c
> > > @@ -1055,6 +1055,11 @@ static int r100_cp_init_microcode(struct radeo=
n_device *rdev)
> > >                  (rdev->family =3D=3D CHIP_RV570)) {
> > >               DRM_INFO("Loading R500 Microcode\n");
> > >               fw_name =3D FIRMWARE_R520;
> > > +     } else {
> > > +             pr_err("radeon_cp: Failed to load firmware \"%d\"\n",
> > > +                     rdev->family);
> > > +             err =3D -EINVAL;
> > > +             goto out;
> > >       }
> > >
> > >       err =3D request_firmware(&rdev->me_fw, fw_name, rdev->dev);
> > > @@ -1067,6 +1072,8 @@ static int r100_cp_init_microcode(struct radeon=
_device *rdev)
> > >               release_firmware(rdev->me_fw);
> > >               rdev->me_fw =3D NULL;
> > >       }
> > > +
> > > +out:
> >
> > That looks superfluous, just return -EINVAL directly in the else case a=
bove.
> >
> > Apart from that this is for ~15year old hardware. I'm a bit reluctant
> > adding code for something that old even when this change here looks
> > harmless.
> >
> > Is there a plan to complain about that in an automated checker? If yes
> > then the change is probably justified, if no then I would rather not do=
 it.
> The warning is emitted when I invoke following commands in ubuntu
> 22.04 (ppc64le)
> linux$make allmodconfig
> linux$make drivers/gpu/drm/radeon/r100.o (a quick alternative to 'make -j=
$nproc)
the command should be make -j(number of CPUs in my machine), please don't i=
nvoke
'make -j$nproc' which is my mistake, this command is very dangerous,
and make my machine hung ;-(

Sorry for the trouble
Thanks again
Zhouyi
> But everything is OK when I invoke following commands in ubuntu 22.04 (pp=
c64le)
> linux$make allmodconfig LLVM=3D1
> linux$make drivers/gpu/drm/radeon/r100.o LLVM=3D1
>
> And I can't reproduce the warning in the x86 environment, so I guess
> this phenomenon
> is toolchain related ;-)
>
> Thanks again
> Regards,
> Zhouyi
> >
> > Regards,
> > Christian.
> >
> > >       return err;
> > >   }
> > >
> >