Hi Nicolas, I love your patch! Perhaps something to improve: [auto build test WARNING on next-20201001] [also build test WARNING on v5.9-rc7] [cannot apply to robh/for-next arm64/for-next/core hnaz-linux-mm/master linus/master v5.9-rc7 v5.9-rc6 v5.9-rc5] [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/Nicolas-Saenz-Julienne/arm64-Default-to-32-bit-wide-ZONE_DMA/20201002-002007 base: d39294091fee6b89d9c4a683bb19441b25098330 config: arm64-randconfig-r005-20200930 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project bcd05599d0e53977a963799d6ee4f6e0bc21331b) 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 # install arm64 cross compiling tool for clang build # apt-get install binutils-aarch64-linux-gnu # https://github.com/0day-ci/linux/commit/7d073ab6c280772b1bcf9e337528be2138d0bc85 git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Nicolas-Saenz-Julienne/arm64-Default-to-32-bit-wide-ZONE_DMA/20201002-002007 git checkout 7d073ab6c280772b1bcf9e337528be2138d0bc85 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All warnings (new ones prefixed by >>): >> drivers/of/fdt.c:1202:13: warning: no previous prototype for function 'early_init_dt_update_zone_dma_bits' [-Wmissing-prototypes] void __init early_init_dt_update_zone_dma_bits(void) ^ drivers/of/fdt.c:1202:1: note: declare 'static' if the function is not intended to be used outside of this translation unit void __init early_init_dt_update_zone_dma_bits(void) ^ static 1 warning generated. vim +/early_init_dt_update_zone_dma_bits +1202 drivers/of/fdt.c 1201 > 1202 void __init early_init_dt_update_zone_dma_bits(void) 1203 { 1204 unsigned long dt_root = of_get_flat_dt_root(); 1205 1206 if (of_flat_dt_is_compatible(dt_root, "brcm,bcm2711")) 1207 zone_dma_bits = 30; 1208 } 1209 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org