Hi Alan, Kernel build failed on tree: git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-next head: 40c9f61eae9098212b6906f29f30f08f7a19b5e2 commit: 2655a2c76f80d91da34faa8f4e114d1793435ed3 [6/9] 8250: use the 8250 register interface not the legacy one config: i386-randconfig-usb7 (attached as .config) All related error/warning messages: drivers/misc/ibmasm/uart.c:57:2: error: implicit declaration of function 'serial8250_register_port' [-Werror=implicit-function-declaration] drivers/tty/serial/8250/8250.c: In function 'serial8250_shutdown': drivers/tty/serial/8250/8250.c:1666:18: warning: 'i' may be used uninitialized in this function [-Wmaybe-uninitialized] drivers/tty/serial/8250/8250.c:1646:19: note: 'i' was declared here drivers/tty/serial/8250/8250.c: In function 'serial8250_startup': drivers/tty/serial/8250/8250.c:1625:2: warning: 'i' may be used uninitialized in this function [-Wmaybe-uninitialized] drivers/tty/serial/8250/8250.c:1598:19: note: 'i' was declared here vim +57 drivers/misc/ibmasm/uart.c 54 uport.iotype = UPIO_MEM; 55 uport.membase = iomem_base; 56 > 57 sp->serial_line = serial8250_register_port(&uport); 58 if (sp->serial_line < 0) { 59 dev_err(sp->dev, "Failed to register serial port\n"); 60 return; --- 0-DAY kernel build testing backend Open Source Technology Centre Fengguang Wu Intel Corporation