[PATCH 2/2] serial: core: Preserve termios c_cflag for console resume

From: Peter Hurley
Date: Wed Jun 04 2014 - 10:16:49 EST


When a tty is opened for the serial console, the termios c_cflag
settings are inherited from the console line settings.
However, if the tty is subsequently closed, the termios settings
are lost. This results in a garbled console if the console is later
suspended and resumed.

Preserve the termios c_cflag for the serial console when the tty
is shutdown; this reflects the most recent line settings.

Fixes: Bugzilla #69751, 'serial console does not wake from S3'
Reported-by: Valerio Vanni <valerio.vanni@xxxxxxxxx>
Cc: Alan Cox <alan@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/serial_core.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 498b149..a67861c 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -239,6 +239,9 @@ static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
/*
* Turn off DTR and RTS early.
*/
+ if (uart_console(uport) && tty)
+ uport->cons->cflag = tty->termios.c_cflag;
+
if (!uart_console(uport) &&
(!tty || (tty->termios.c_cflag & HUPCL)))
uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
--
1.9.1

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