linux-kernel - Re: linux-next: Tree for Jun 15 (drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu

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Date:   Wed, 15 Jun 2022 16:45:16 -0400
From:   Alex Deucher <alexdeucher@...il.com>
To:     Nathan Chancellor <nathan@...nel.org>
Cc:     Randy Dunlap <rdunlap@...radead.org>,
        Stephen Rothwell <sfr@...b.auug.org.au>,
        Linux Next Mailing List <linux-next@...r.kernel.org>,
        "Pan, Xinhui" <Xinhui.Pan@....com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        amd-gfx list <amd-gfx@...ts.freedesktop.org>,
        Alex Deucher <alexander.deucher@....com>,
        Christian König <christian.koenig@....com>,
        Bhanuprakash Modem <bhanuprakash.modem@...el.com>
Subject: Re: linux-next: Tree for Jun 15 (drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c)

On Wed, Jun 15, 2022 at 4:24 PM Nathan Chancellor <nathan@...nel.org> wrote:
>
> On Wed, Jun 15, 2022 at 03:28:52PM -0400, Alex Deucher wrote:
> > On Wed, Jun 15, 2022 at 3:01 PM Randy Dunlap <rdunlap@...radead.org> wrote:
> > >
> > >
> > >
> > > On 6/14/22 23:01, Stephen Rothwell wrote:
> > > > Hi all,
> > > >
> > > > Changes since 20220614:
> > > >
> > >
> > > on i386:
> > > # CONFIG_DEBUG_FS is not set
> > >
> > >
> > > ../drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c: In function ‘amdgpu_dm_crtc_late_register’:
> > > ../drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:6599:2: error: implicit declaration of function ‘crtc_debugfs_init’; did you mean ‘amdgpu_debugfs_init’? [-Werror=implicit-function-declaration]
> > >   crtc_debugfs_init(crtc);
> > >   ^~~~~~~~~~~~~~~~~
> > >   amdgpu_debugfs_init
> > >
> > >
> > > Full randconfig file is attached.
> >
> > I tried building with your config and I can't repro this.  As Harry
> > noted, that function and the whole secure display feature depend on
> > debugfs.  It should never be built without CONFIG_DEBUG_FS.  See
> > drivers/gpu/drm/amd/display/Kconfig:
> >
> > > config DRM_AMD_SECURE_DISPLAY
> > >         bool "Enable secure display support"
> > >         default n
> > >         depends on DEBUG_FS
> > >         depends on DRM_AMD_DC_DCN
> > >         help
> > >             Choose this option if you want to
> > >             support secure display
> > >
> > >             This option enables the calculation
> > >             of crc of specific region via debugfs.
> > >             Cooperate with specific DMCU FW.
> >
> > amdgpu_dm_crtc_late_register is guarded by
> > CONIG_DRM_AMD_SECURE_DISPLAY.  It's not clear to me how we could hit
> > this.
>
> I think the problem is that you are not looking at the right tree.
>
> The kernel test robot reported [1] [2] this error is caused by commit
> 4cd79f614b50 ("drm/amd/display: Move connector debugfs to drm"), which
> is in the drm-misc tree on the drm-misc-next branch. That change removes
> the #ifdef around amdgpu_dm_crtc_late_register(), meaning that
> crtc_debugfs_init() can be called without CONFIG_DRM_AMD_SECURE_DISPLAY
> and CONFIG_DEBUG_FS.
>
>   $ git show -s --format='%h ("%s")'
>   abf0ba5a34ea ("drm/bridge: it6505: Add missing CRYPTO_HASH dependency")
>
>   $ make -skj"$(nproc)" ARCH=x86_64 mrproper defconfig
>
>   $ scripts/config -d BLK_DEV_IO_TRACE -d DEBUG_FS -e DRM_AMDGPU
>
>   $ make -skj"$(nproc)" ARCH=x86_64 olddefconfig drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.o
>   drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c: In function ‘amdgpu_dm_crtc_late_register’:
>   drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:6622:9: error: implicit declaration of function ‘crtc_debugfs_init’; did you mean ‘amdgpu_debugfs_init’? [-Werror=implicit-function-declaration]
>    6622 |         crtc_debugfs_init(crtc);
>         |         ^~~~~~~~~~~~~~~~~
>         |         amdgpu_debugfs_init
>   cc1: all warnings being treated as errors
>
> Contrast that with the current top of your tree:
>
>   $ git show -s --format='%h ("%s")'
>   c435f61d0eb3 ("drm/amd/display: Drop unnecessary guard from DC resource")
>
>   $ make -skj"$(nproc)" ARCH=x86_64 mrproper defconfig
>
>   $ scripts/config -d BLK_DEV_IO_TRACE -d DEBUG_FS -e DRM_AMDGPU
>
>   $ make -skj"$(nproc)" ARCH=x86_64 olddefconfig drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.o
>
>   $ echo $?
>   0
>
> Randy's patch [3] seems like it should resolve the issue just fine but
> it needs to be applied to drm-misc-next, not the amdgpu tree.

Thanks for tracking this down.  I think something like the attached
patch is cleaner since the whole thing is only valid for debugfs.

Alex


>
> [1]: https://lore.kernel.org/202205241843.8EWKesIA-lkp@intel.com/
> [2]: https://lore.kernel.org/202205240207.KmDLuSrC-lkp@intel.com/
> [3]: https://lore.kernel.org/20220614155726.26211-1-rdunlap@infradead.org/
>
> Cheers,
> Nathan

View attachment "0001-drm-amdgpu-display-fix-build-when-CONFIG_DEBUG_FS-is.patch" of type "text/x-patch" (1612 bytes)