if ((!file || !tty_hung_up_p(file)) &&
!(tty->flags & (1 << TTY_IO_ERROR))) {
uart_update_mctrl(port, set, clear);
ret = 0;
}
if ((!file || !tty_hung_up_p(file)) &&
!(tty->flags & (1 << TTY_IO_ERROR))) {
uart_update_mctrl(port, set, clear);
ret = 0;
}