From 0055197e984e5fbe6f48f37fc50dd30254915493 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Wed, 17 Aug 2011 13:48:15 +0200 Subject: [PATCH] TTY: serial, document ignoring of uart->ops->startup error When a user has SYS_ADMIN capabilities and uart->ops->startup returns an error in uart_startup, we silently drop the error. We then return 0 and behave as if it didn't fail. (Not quite, since we set TTY_IO_ERROR bit and leave ASYNC_INITIALIZED bit cleared.) This all is to allow setserial to work with improperly configured or unconfigured ports. User can thus set port properties and reconfigure properly. This patch only documents this behavior. Signed-off-by: Jiri Slaby Cc: Alan Cox Cc: Russel King Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/serial_core.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index db7912cb7ae0..a3efbea5dbba 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -200,6 +200,11 @@ static int uart_startup(struct tty_struct *tty, struct uart_state *state, int in clear_bit(TTY_IO_ERROR, &tty->flags); } + /* + * This is to allow setserial on this port. People may want to set + * port/irq/type and then reconfigure the port properly if it failed + * now. + */ if (retval && capable(CAP_SYS_ADMIN)) retval = 0; -- 2.20.1