tree: https://github.com/frank-w/BPI-R2-4.14 5.15-rtl8367dsa head: 8ba8cffcee5e30e3adb60b08dd018f353fda4249 commit: 8ba8cffcee5e30e3adb60b08dd018f353fda4249 [61/61] net: dsa: try to add the slave-mii bus config: sh-allmodconfig (attached as .config) compiler: sh4-linux-gcc (GCC) 11.2.0 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/frank-w/BPI-R2-4.14/commit/8ba8cffcee5e30e3adb60b08dd0... git remote add frank-w-bpi-r2-4.14 https://github.com/frank-w/BPI-R2-4.14 git fetch --no-tags frank-w-bpi-r2-4.14 5.15-rtl8367dsa git checkout 8ba8cffcee5e30e3adb60b08dd018f353fda4249 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=sh 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 >>): drivers/net/dsa/rtl8367s_mdio.c:2303:6: error: no previous prototype for 'init_gsw' [-Werror=missing-prototypes] 2303 | void init_gsw(void) | ^~~~~~~~ 2347 | int rtl8367c_setup_mdio(struct rtk_gsw *gsw) | ^~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors vim +/rtl8367c_setup_mdio +2347 drivers/net/dsa/rtl8367s_mdio.c 2346 2348 { 2349 struct device_node *mdio_np; 2350 int ret; 2351 2352 /*mdio_np = of_get_compatible_child(smi->dev->of_node, "realtek,smi-mdio"); 2353 if (!mdio_np) { 2354 dev_err(smi->dev, "no MDIO bus node\n"); 2355 return -ENODEV; 2356 }*/ 2357 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org