[PATCH] serial: fix termios settings in open

From: Arnd Bergmann
Date: Tue Jun 29 2010 - 16:31:59 EST

Move termios initialization in open into uart_dtr_rts to make sure
it always gets called when necessary. Based on a suggestion from
Alan Cox.

Alan writes:
Ok this sort of makes sense. Something isn't getting initialised and both
getty and minicom will do a termios set which is sorting it out.
This is occurring because the generic block_til_ready sets
ASYNCB_NORMAL_ACTIVE so the termios updating gets skipped.

This patch should cure it and then we can think about doing it more
elegantly by getting the serial layer to use tty_port_open, kfifo and
the like and removing the tons of repeated crap in all the drivers.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
Reported-by: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>

Greg, please apply to you tty series. I thought there was a bug
in this patch but it turns out that this was incorrect. There
is still something fishy on my system with hardware flow control,
but it seems to be a preexisting condition, so this patch is actually
good, unlike what I said before. Please apply next to "serial: Use
block_til_ready helper", which introduces the ploblem.

drivers/serial/serial_core.c | 19 +++++++++----------
1 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c
index 78b1eac..cd85112 100644
--- a/drivers/serial/serial_core.c
+++ b/drivers/serial/serial_core.c
@@ -1533,8 +1533,16 @@ static void uart_dtr_rts(struct tty_port *port, int onoff)
struct uart_state *state = container_of(port, struct uart_state, port);
struct uart_port *uport = state->uart_port;

- if (onoff)
+ if (onoff) {
uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
+ /*
+ * If this is the first open to succeed,
+ * adjust things to suit.
+ */
+ if (!test_and_set_bit(ASYNCB_NORMAL_ACTIVE, &port->flags))
+ uart_update_termios(port->tty, state);
+ }
uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
@@ -1649,15 +1657,6 @@ static int uart_open(struct tty_struct *tty, struct file *filp)
if (retval == 0)
retval = tty_port_block_til_ready(port, tty, filp);

- /*
- * If this is the first open to succeed, adjust things to suit.
- */
- if (retval == 0 && !(port->flags & ASYNC_NORMAL_ACTIVE)) {
- set_bit(ASYNCB_NORMAL_ACTIVE, &port->flags);
- uart_update_termios(tty, state);
- }
return retval;

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