Hi Geert, I love your patch! Yet something to improve: [auto build test ERROR on robh/for-next] [also build test ERROR on staging/staging-testing linus/master v5.14-rc1 next-20210714] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Geert-Uytterhoeven/auxdisplay-ht... base: https://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git for-next config: arc-randconfig-r016-20210715 (attached as .config) compiler: arc-elf-gcc (GCC) 10.3.0 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://github.com/0day-ci/linux/commit/a8d991401542b45f91eb59e1cdf24fd6c... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Geert-Uytterhoeven/auxdisplay-ht16k33-Add-character-display-support/20210714-231351 git checkout a8d991401542b45f91eb59e1cdf24fd6c419360e # save the attached .config to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross O=build_dir ARCH=arc SHELL=/bin/bash 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 >>): arc-elf-ld: lib/stackdepot.o: in function `filter_irq_stacks': stackdepot.c:(.text+0x8): undefined reference to `__irqentry_text_start' arc-elf-ld: stackdepot.c:(.text+0x8): undefined reference to `__irqentry_text_start' arc-elf-ld: stackdepot.c:(.text+0x28): undefined reference to `__irqentry_text_end' arc-elf-ld: stackdepot.c:(.text+0x28): undefined reference to `__irqentry_text_end' arc-elf-ld: stackdepot.c:(.text+0x38): undefined reference to `__softirqentry_text_start' arc-elf-ld: stackdepot.c:(.text+0x38): undefined reference to `__softirqentry_text_start' arc-elf-ld: stackdepot.c:(.text+0x40): undefined reference to `__softirqentry_text_end' arc-elf-ld: stackdepot.c:(.text+0x40): undefined reference to `__softirqentry_text_end' arc-elf-ld: drivers/auxdisplay/ht16k33.o: in function `ht16k33_probe': --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org