linux-kernel - Re: [PATCH] drm/radeon/r100: enhance error handling in r100_cp_init

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Message-ID: <CAABZP2ximP0kiSSXSw51fhrt0EuZMLUHeonzS2VGSUwm-QEF3w@mail.gmail.com>
Date: Tue, 28 May 2024 09:45:03 +0800
From: Zhouyi Zhou <zhouzhouyi@...il.com>
To: Christian König <christian.koenig@....com>
Cc: alexander.deucher@....com, Xinhui.Pan@....com, airlied@...il.com, 
	daniel@...ll.ch, chris@...isdown.name, amd-gfx@...ts.freedesktop.org, 
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
	rcu@...r.kernel.org, lance@...osl.org
Subject: Re: [PATCH] drm/radeon/r100: enhance error handling in r100_cp_init_microcode

Fix some error in my previous email

On Tue, May 28, 2024 at 9:36 AM Zhouyi Zhou <zhouzhouyi@...il.com> wrote:
>
> Thanks for reviewing the patch
>
> On Mon, May 27, 2024 at 3:58 PM Christian König
> <christian.koenig@....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 ‘r100_cp_init_microcode’,
> > >      inlined from ‘r100_cp_init’ at drivers/gpu/drm/radeon/r100.c:1136:7:
> > > ./include/linux/printk.h:457:44: warning: ‘%s’ directive argument is null [-Wformat-overflow=]
> > >    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_microcode
> > > return with -EINVAL when none of chip families is matched.
> > >
> > > Signed-off-by: Zhouyi Zhou <zhouzhouyi@...il.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/r100.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 radeon_device *rdev)
> > >                  (rdev->family == CHIP_RV570)) {
> > >               DRM_INFO("Loading R500 Microcode\n");
> > >               fw_name = FIRMWARE_R520;
> > > +     } else {
> > > +             pr_err("radeon_cp: Failed to load firmware \"%d\"\n",
> > > +                     rdev->family);
> > > +             err = -EINVAL;
> > > +             goto out;
> > >       }
> > >
> > >       err = 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 = NULL;
> > >       }
> > > +
> > > +out:
> >
> > That looks superfluous, just return -EINVAL directly in the else case above.
> >
> > 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$nproc)
the command should be make -j(number of CPUs in my machine), please don't invoke
'make -j$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 (ppc64le)
> linux$make allmodconfig LLVM=1
> linux$make drivers/gpu/drm/radeon/r100.o LLVM=1
>
> 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;
> > >   }
> > >
> >