There is an ordering problem with closing a UART in the serial core. If the line discipline is throttling the port when close is called, it tries to unthrottle the port which, in the case of soft flow, tries to send the XON character. This doesn't work well since at this point the uart has been shutdown. The simple reordering shown below will seems to fix the problem, but please comment if there are other side effects I am not seeing. Eugene T. Bordenkircher --- linux_kernel/drivers/serial/serial_core.c.orig 2009-08-13 14:58:04.000000000 -0700 +++ linux_kernel/drivers/serial/serial_core.c 2009-08-13 15:29:02.000000000 -0700 @@ -1317,11 +1317,11 @@ uart_wait_until_sent(tty, port->timeout); } + tty_ldisc_flush(tty); + uart_shutdown(state); uart_flush_buffer(tty); - tty_ldisc_flush(tty); - tty->closing = 0; state->info.port.tty = NULL; -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html