Hi Arnd, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 1c273e10bc0cc7efb933e0ca10e260cdfc9f0b8c commit: a734bbf694270dca8594a5c33375867dc31503f5 m68k: m68328: move platform code to separate files date: 3 months ago config: m68k-randconfig-r015-20210318 (attached as .config) compiler: m68k-linux-gcc (GCC) 9.3.0 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://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout a734bbf694270dca8594a5c33375867dc31503f5 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=m68k 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 >>): arch/m68k/68000/dragen2.c:38:13: warning: no previous prototype for 'init_dragen2' [-Wmissing-prototypes] 38 | void __init init_dragen2(char *command, int size) | ^~~~~~~~~~~~ arch/m68k/68000/dragen2.c: In function 'init_dragen2': 73 | LSSA = (long) screen_bits; | ^~~~~~~~~~~ arch/m68k/68000/dragen2.c:73:16: note: each undeclared identifier is reported only once for each function it appears in vim +/screen_bits +73 arch/m68k/68000/dragen2.c 45 46 /* CSGB Init */ 47 CSGBB = 0x4000; 48 CSB = 0x1a1; 49 50 /* CS8900 init */ 51 /* PK3: hardware sleep function pin, active low */ 52 PKSEL |= PK(3); /* select pin as I/O */ 53 PKDIR |= PK(3); /* select pin as output */ 54 PKDATA |= PK(3); /* set pin high */ 55 56 /* PF5: hardware reset function pin, active high */ 57 PFSEL |= PF(5); /* select pin as I/O */ 58 PFDIR |= PF(5); /* select pin as output */ 59 PFDATA &= ~PF(5); /* set pin low */ 60 61 /* cs8900 hardware reset */ 62 PFDATA |= PF(5); 63 { int i; for (i = 0; i < 32000; ++i); } 64 PFDATA &= ~PF(5); 65 66 /* INT1 enable (cs8900 IRQ) */ 67 PDPOL &= ~PD(1); /* active high signal */ 68 PDIQEG &= ~PD(1); 69 PDIRQEN |= PD(1); /* IRQ enabled */ 70 71 #ifdef CONFIG_INIT_LCD 72 /* initialize LCD controller */ --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org