[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <9e77ccc3-07db-f1fe-ef99-981852d4772b@infradead.org>
Date: Thu, 3 Aug 2023 19:01:34 -0700
From: Randy Dunlap <rdunlap@...radead.org>
To: Adam Ford <aford173@...il.com>,
Aleksandr Nogikh <nogikh@...gle.com>
Cc: l.stach@...gutronix.de, inki.dae@...sung.com,
jagan@...rulasolutions.com, m.szyprowski@...sung.com,
airlied@...il.com, daniel@...ll.ch,
dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
syzkaller@...glegroups.com, dvyukov@...gle.com
Subject: Re: drivers/gpu/drm/bridge/samsung-dsim.c link error
Hi--
On 8/3/23 08:24, Adam Ford wrote:
> On Thu, Aug 3, 2023 at 9:42 AM Aleksandr Nogikh <nogikh@...gle.com> wrote:
>>
>> Hello,
>>
>> We've been seing the following linker error on arm64 syzbot instances:
>>
>> ld.lld: error: undefined symbol: phy_mipi_dphy_get_default_config_for_hsclk
>>>>> referenced by samsung-dsim.c:731 (drivers/gpu/drm/bridge/samsung-dsim.c:731)
>>>>> drivers/gpu/drm/bridge/samsung-dsim.o:(samsung_dsim_init) in archive vmlinux.a
>>
>> Steps to reproduce on the latest linux-next:
>>
>> $ git checkout next-20230803
>> $ wget -O '.config' 'https://raw.githubusercontent.com/google/syzkaller/master/dashboard/config/linux/upstream-arm64-kasan.config'
>> $ make CC=clang ARCH=arm64 LD=ld.lld CROSS_COMPILE=aarch64-linux-gnu- olddefconfig
>>
>> This also prints:
>>
>> WARNING: unmet direct dependencies detected for GENERIC_PHY_MIPI_DPHY
>> Depends on [n]: GENERIC_PHY [=n]
>> Selected by [y]:
>> - DRM_NWL_MIPI_DSI [=y] && DRM_BRIDGE [=y] && DRM [=y] && COMMON_CLK [=y] && OF [=y] && HAS_IOMEM [=y]
>> - DRM_SAMSUNG_DSIM [=y] && DRM [=y] && DRM_BRIDGE [=y] && COMMON_CLK [=y] && OF [=y] && HAS_IOMEM [=y]
>>
>> $ make CC=clang ARCH=arm64 LD=ld.lld CROSS_COMPILE=aarch64-linux-gnu- -j$(nproc)
>>
>> The kernel should have still compiled fine even despite the message above, right?
No. See drivers/Makefile:
obj-$(CONFIG_GENERIC_PHY) += phy/
so the drivers/phy/ subdir is only built when CONFIG_GENERIC_PHY is set,
but it's not set.
>> Could you please take a look?
>
> GENERIC_PHY_MIPI_DPHY was enabled to use
> phy_mipi_dphy_get_default_config() which takes in the pixel clock,
> bits-per-pixel, number of lanes and phy structure. It applies a bunch
> of math based on the info passed and fills in the structure, but that
> function itself doesn't appear to be referencing phy code, so it's
> likely safe.
>
> I think this can be resolved by enabling GENERIC_PHY. I just checked
> linux-next and when I built the arm64 defconfig, it enables
> GENERIC_PHY=y, so I don't think this is an issue. I also checked the
defconfig doesn't matter in this case. The .config that was provided has:
# CONFIG_GENERIC_PHY is not set
CONFIG_GENERIC_PHY_MIPI_DPHY=y
but yes, selecting GENERIC_PHY (needed in 3 places) does fix the warnings
and build error. 2 instance in drm/bridge/Kconfig and one in
drm/bridge/cadence/Kconfig (found by inspection).
> multi_v7_defconfig for ARM and it also sets GENERIC_PHY=y for 32-bit
> ARM people using some of the Exynos boards.
>
> I don't know what version of Linux you're trying to build, but I can't
> replicate your issue.
I had no problem replicating the kconfig warnings and build error.
--
~Randy
Powered by blists - more mailing lists