tree: git://git.ti.com/ti-linux-kernel/ti-linux-kernel.git ti-linux-5.4.y head: eacdd0a4f060e33d46290dec099c5242e58acfa9 commit: 57fe8746100f3f05dd85a6a2e3360532fd67fda3 [9992/9999] serial: 8250: add pruss uart driver config: arm64-allyesconfig (attached as .config) compiler: aarch64-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 git checkout 57fe8746100f3f05dd85a6a2e3360532fd67fda3 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>, old ones prefixed by <<): drivers/tty/serial/8250/8250_pruss.c: In function 'pruss8250_set_divisor': 131 | serial_port_out(port, PRUSS_UART_MDR, ~PRUSS_UART_MDR_OSM_SEL); vim +131 drivers/tty/serial/8250/8250_pruss.c 121 122 static void pruss8250_set_divisor(struct uart_port *port, unsigned int baud, 123 unsigned int quot, unsigned int quot_frac) 124 { 125 serial8250_do_set_divisor(port, baud, quot, quot_frac); 126 if (quot_frac == PRUSS_UART_MDR_13X_MODE) 127 /* set mdr for 13x */ 128 serial_port_out(port, PRUSS_UART_MDR, PRUSS_UART_MDR_OSM_SEL); 129 else 130 /* set mdr for 16x */ 132 } 133 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org