Re: [next] arm: panel-edp.c:(.text+0xb74): undefined reference to `drm_panel_dp_aux_backlight'

[Ard Biesheuvel]

On Wed, 2 Feb 2022 at 10:08, Thomas Zimmermann <tzimmermann@xxxxxxx> wrote:
>
> Hi
>
> Am 02.02.22 um 10:02 schrieb Naresh Kamboju:
> > Following builds failed on Linux next 20220202 arm architecture.
> >    - arm-gcc-10-omap2plus_defconfig
> >    - arm-clang-nightly-shmobile_defconfig
> >    - arm-gcc-8-lpc32xx_defconfig
> >    - arm-clang-13-shmobile_defconfig
> >    - arm-gcc-10-shmobile_defconfig
> >    - arm-clang-11-shmobile_defconfig
> >    - arm-clang-11-omap2plus_defconfig
> >    - arm-clang-13-omap2plus_defconfig
> >    - arm-clang-11-lpc32xx_defconfig
> >    - arm-gcc-8-omap2plus_defconfig
> >    - arm-gcc-9-vexpress_defconfig
> >    - arm-clang-nightly-lpc32xx_defconfig
> >    - arm-gcc-9-shmobile_defconfig
> >    - arm-clang-13-lpc32xx_defconfig
> >    - arm-gcc-10-sama5_defconfig
> >    - arm-clang-11-vexpress_defconfig
> >    - arm-clang-11-sama5_defconfig
> >    - arm-gcc-9-omap2plus_defconfig
> >    - arm-clang-nightly-sama5_defconfig
> >    - arm-clang-13-vexpress_defconfig
> >    - arm-clang-nightly-vexpress_defconfig
> >    - arm-gcc-9-lpc32xx_defconfig
> >    - arm-clang-12-vexpress_defconfig
> >    - arm-gcc-10-vexpress_defconfig
> >    - arm-clang-12-shmobile_defconfig
> >    - arm-gcc-11-omap2plus_defconfig
> >    - arm-gcc-9-sama5_defconfig
> >    - arm-gcc-8-shmobile_defconfig
> >    - arm-gcc-10-lpc32xx_defconfig
> >    - arm-clang-12-omap2plus_defconfig
> >    - arm-gcc-8-vexpress_defconfig
> >    - arm-clang-12-sama5_defconfig
> >    - arm-clang-nightly-omap2plus_defconfig
> >    - arm-gcc-11-lpc32xx_defconfig
> >    - arm-gcc-11-sama5_defconfig
> >    - arm-gcc-11-shmobile_defconfig
> >    - arm-gcc-11-vexpress_defconfig
> >    - arm-gcc-8-sama5_defconfig
> >    - arm-clang-13-sama5_defconfig
> >    - arm-clang-12-lpc32xx_defconfig
> >
> >
> > make --silent --keep-going --jobs=8  ARCH=arm
> > CROSS_COMPILE=arm-linux-gnueabihf- 'CC=sccache
> > arm-linux-gnueabihf-gcc' 'HOSTCC=sccache gcc' vexpress_defconfig
> > make --silent --keep-going --jobs=8  ARCH=arm
> > CROSS_COMPILE=arm-linux-gnueabihf- 'CC=sccache
> > arm-linux-gnueabihf-gcc' 'HOSTCC=sccache gcc'
> > arm-linux-gnueabihf-ld: drivers/gpu/drm/panel/panel-edp.o: in function
> > `panel_edp_probe':
> > panel-edp.c:(.text+0xb74): undefined reference to `drm_panel_dp_aux_backlight'
> > make[1]: *** [/builds/linux/Makefile:1222: vmlinux] Error 1
> >
> >
> > Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>
> >
> > meta data:
> > -----------
> >      git describe: next-20220202
> >      git_repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
> >      target_arch: arm
> >      kconfig: vexpress_defconfig
> >      toolchain: gcc-11
> >
> > Build log:
> > -------------
> > https://builds.tuxbuild.com/24XRim72vFXix6l6MdAJNENy6je/
> >
> > Steps to reproduce:
> > --------------------
> > # To install tuxmake on your system globally:
> > # sudo pip3 install -U tuxmake
> > #
> > # See https://docs.tuxmake.org/ for complete documentation.
> > # Original tuxmake command with fragments listed below.
> >
> > tuxmake --runtime podman --target-arch arm --toolchain gcc-11
> > --kconfig vexpress_defconfig
> >
> > tuxmake --runtime podman --target-arch arm --toolchain gcc-11
> > --kconfig https://builds.tuxbuild.com/24XRim72vFXix6l6MdAJNENy6je/config
>
> You'll now need
>
>    CONFIG_DRM_DP_HELPER=y
>
> in your config.
>

That should never be the solution for linker errors such as this one.

If CONFIG_DRM_PANEL_EDP relies on something provided by
CONFIG_DRM_DP_HELPER, it should select it or depend on it in Kconfig.