Hi Masahiro, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: a5dc8300df75e8b8384b4c82225f1e4a0b4d9b55 commit: def2fbffe62c00c330c7f41584a356001179c59c kconfig: allow symbols implied by y to become m date: 3 months ago config: i386-randconfig-a004-20200616 (attached as .config) compiler: gcc-9 (Debian 9.3.0-13) 9.3.0 reproduce (this is a W=1 build): git checkout def2fbffe62c00c330c7f41584a356001179c59c # save the attached .config to linux build tree make W=1 ARCH=i386 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>, old ones prefixed by <<): ld: drivers/gpu/drm/bridge/sil-sii8620.o: in function `sii8620_remove': drivers/gpu/drm/bridge/sil-sii8620.c:2355: undefined reference to `extcon_unregister_notifier' ld: drivers/gpu/drm/bridge/sil-sii8620.o: in function `sii8620_extcon_init': drivers/gpu/drm/bridge/sil-sii8620.c:2179: undefined reference to `extcon_find_edev_by_node' ld: drivers/gpu/drm/bridge/sil-sii8620.o: in function `sii8620_extcon_work': drivers/gpu/drm/bridge/sil-sii8620.c:2139: undefined reference to `extcon_get_state' --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org