Hi "Maciej, I love your patch! Perhaps something to improve: [auto build test WARNING on linus/master] [also build test WARNING on v5.13-rc6 next-20210616] [cannot apply to tty/tty-testing] [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/Maciej-W-Rozycki/serial-8250-Fix... base: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 94f0b2d4a1d0c52035aef425da5e022bd2cb1c71 config: x86_64-randconfig-s021-20210617 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce: # apt-get install sparse # sparse version: v0.6.3-341-g8af24329-dirty # https://github.com/0day-ci/linux/commit/d3a55e8397b71f343ef931cd098d42a13... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Maciej-W-Rozycki/serial-8250-Fixes-for-Oxford-Semiconductor-950-UARTs/20210616-201047 git checkout d3a55e8397b71f343ef931cd098d42a13faf9047 # save the attached .config to linux build tree make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' W=1 ARCH=x86_64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; sparse warnings: (new ones prefixed by >>) vim +1258 drivers/tty/serial/8250/8250_pci.c 1241 1242 /* 1243 * For Tornado devices we force MCR[7] set for the Divide-by-M N/8 baud rate 1244 * generator prescaler (CPR and CPR2). Otherwise no prescaler would be used. 1245 */ 1246 static int pci_oxsemi_tornado_setup(struct serial_private *priv, 1247 const struct pciserial_board *board, 1248 struct uart_8250_port *up, int idx) 1249 { 1250 struct pci_dev *dev = priv->dev; 1251 1252 /* OxSemi Tornado devices are all 0xCxxx */ 1253 if (dev->vendor == PCI_VENDOR_ID_OXSEMI && 1254 (dev->device & 0xF000) == 0xC000) { 1255 up->port.get_divisor = pci_oxsemi_tornado_get_divisor; 1256 up->port.set_divisor = pci_oxsemi_tornado_set_divisor; 1257 1259 up->mcr_force = UART_MCR_CLKSEL; 1260 } 1261 1262 return pci_default_setup(priv, board, up, idx); 1263 } 1264 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org