Re: ld.lld: error: undefined symbol: drm_gem_fb_get_obj

[Nathan Chancellor <nathan@kernel.org>]

On Fri, Aug 26, 2022 at 10:26:43AM +0200, Linus Walleij wrote:
> On Mon, Aug 22, 2022 at 9:27 AM kernel test robot <lkp@intel.com> wrote:
> 
> > tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head:   1c23f9e627a7b412978b4e852793c5e3c3efc555
> > commit: 57f6190a60ecc19f1ddddac0d7ea6524229271a9 drm/panel: ws2401: Add driver for WideChips WS2401
> > date:   1 year, 1 month ago
> > config: x86_64-randconfig-a002-20220822 (https://download.01.org/0day-ci/archive/20220822/202208221506.0Lo051G4-lkp@intel.com/config)
> > compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
> > reproduce (this is a W=1 build):
> >         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> >         chmod +x ~/bin/make.cross
> >         # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=57f6190a60ecc19f1ddddac0d7ea6524229271a9
> >         git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> >         git fetch --no-tags linus master
> >         git checkout 57f6190a60ecc19f1ddddac0d7ea6524229271a9
> >         # save the config file
> >         mkdir build_dir && cp config build_dir/.config
> >         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash
> >
> > If you fix the issue, kindly add following tag where applicable
> > Reported-by: kernel test robot <lkp@intel.com>
> >
> > All errors (new ones prefixed by >>):
> >
> > >> ld.lld: error: undefined symbol: drm_gem_fb_get_obj
> >    >>> referenced by drm_mipi_dbi.c:203 (drivers/gpu/drm/drm_mipi_dbi.c:203)
> >    >>>               gpu/drm/drm_mipi_dbi.o:(mipi_dbi_buf_copy) in archive drivers/built-in.a
> >    >>> referenced by drm_mipi_dbi.c:258 (drivers/gpu/drm/drm_mipi_dbi.c:258)
> >    >>>               gpu/drm/drm_mipi_dbi.o:(mipi_dbi_fb_dirty) in archive drivers/built-in.a
> > --
> > >> ld.lld: error: undefined symbol: drm_fb_swab
> >    >>> referenced by drm_mipi_dbi.c:219 (drivers/gpu/drm/drm_mipi_dbi.c:219)
> >    >>>               gpu/drm/drm_mipi_dbi.o:(mipi_dbi_buf_copy) in archive drivers/built-in.a
> > --
> > >> ld.lld: error: undefined symbol: drm_atomic_helper_connector_destroy_state
> >    >>> referenced by drm_mipi_dbi.c
> >    >>>               gpu/drm/drm_mipi_dbi.o:(mipi_dbi_connector_funcs) in archive drivers/built-in.a
> > --
> > >> ld.lld: error: undefined symbol: drm_gem_fb_create_with_dirty
> >    >>> referenced by drm_mipi_dbi.c
> >    >>>               gpu/drm/drm_mipi_dbi.o:(mipi_dbi_mode_config_funcs) in archive drivers/built-in.a
> > --
> > >> ld.lld: error: undefined symbol: drm_atomic_helper_check
> >    >>> referenced by drm_mipi_dbi.c
> >    >>>               gpu/drm/drm_mipi_dbi.o:(mipi_dbi_mode_config_funcs) in archive drivers/built-in.a
> > --
> > >> ld.lld: error: undefined symbol: drm_atomic_helper_commit
> >    >>> referenced by drm_mipi_dbi.c
> >    >>>               gpu/drm/drm_mipi_dbi.o:(mipi_dbi_mode_config_funcs) in archive drivers/built-in.a
> > --
> > >> ld.lld: error: undefined symbol: drm_fb_xrgb8888_to_rgb565
> >    >>> referenced by drm_mipi_dbi.c:224 (drivers/gpu/drm/drm_mipi_dbi.c:224)
> >    >>>               gpu/drm/drm_mipi_dbi.o:(mipi_dbi_buf_copy) in archive drivers/built-in.a
> > --
> > >> ld.lld: error: undefined symbol: drm_fb_memcpy
> >    >>> referenced by drm_mipi_dbi.c:221 (drivers/gpu/drm/drm_mipi_dbi.c:221)
> >    >>>               gpu/drm/drm_mipi_dbi.o:(mipi_dbi_buf_copy) in archive drivers/built-in.a
> > --
> > >> ld.lld: error: undefined symbol: drm_atomic_helper_damage_merged
> >    >>> referenced by drm_mipi_dbi.c:318 (drivers/gpu/drm/drm_mipi_dbi.c:318)
> >    >>>               gpu/drm/drm_mipi_dbi.o:(mipi_dbi_pipe_update) in archive drivers/built-in.a
> > --
> > >> ld.lld: error: undefined symbol: drm_simple_display_pipe_init
> >    >>> referenced by drm_mipi_dbi.c:529 (drivers/gpu/drm/drm_mipi_dbi.c:529)
> >    >>>               gpu/drm/drm_mipi_dbi.o:(mipi_dbi_dev_init_with_formats) in archive drivers/built-in.a
> > --
> > >> ld.lld: error: undefined symbol: drm_atomic_helper_connector_reset
> >    >>> referenced by drm_mipi_dbi.c
> >    >>>               gpu/drm/drm_mipi_dbi.o:(mipi_dbi_connector_funcs) in archive drivers/built-in.a
> 
> I don't understand this error report, please robot, analyze further and come
> back with details on what needs to be fixed.

Seems like this might be the fix?

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 6c2256e8474b..679ad054ea4b 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -31,6 +31,7 @@ menuconfig DRM
 config DRM_MIPI_DBI
 	tristate
 	depends on DRM
+	select DRM_KMS_HELPER
 
 config DRM_MIPI_DSI
 	bool
diff --git a/drivers/gpu/drm/panel/Kconfig b/drivers/gpu/drm/panel/Kconfig
index a9043eacce97..c68b433c8241 100644
--- a/drivers/gpu/drm/panel/Kconfig
+++ b/drivers/gpu/drm/panel/Kconfig
@@ -165,7 +165,6 @@ config DRM_PANEL_ILITEK_IL9322
 config DRM_PANEL_ILITEK_ILI9341
 	tristate "Ilitek ILI9341 240x320 QVGA panels"
 	depends on OF && SPI
-	depends on DRM_KMS_HELPER
 	depends on DRM_GEM_CMA_HELPER
 	depends on BACKLIGHT_CLASS_DEVICE
 	select DRM_MIPI_DBI

drm_mipi_dbi.c uses several functions from the drm_kms_helper-y files
(drivers/gpu/drm/Makefile) but there is nothing to guarantee that
CONFIG_DRM_KMS_HELPER gets selected with CONFIG_DRM_MIPI_DBI. The
'depends on' drop is to remove a circular dependency failure.

For what it's worth, this error is not clang or ld.lld specific, you
would see the same problem with GCC + GNU binutils.

Cheers,
Nathan