linux-kernel - [PATCH] serial: 8250: Fix restoring termios speed after suspend

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Message-Id: <20220924104324.4035-1-pali@kernel.org>
Date:   Sat, 24 Sep 2022 12:43:24 +0200
From:   Pali Rohár <pali@...nel.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jirislaby@...nel.org>
Cc:     linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] serial: 8250: Fix restoring termios speed after suspend

Since commit edc6afc54968 ("tty: switch to ktermios and new framework")
termios speed is no longer stored only in c_cflag member but also in new
additional c_ispeed and c_ospeed members. If BOTHER flag is set in c_cflag
then termios speed is stored only in these new members.

Since commit 027b57170bf8 ("serial: core: Fix initializing and restoring
termios speed") termios speed is available also in struct console.

So properly restore also c_ispeed and c_ospeed members after suspend to fix
restoring termios speed which is not represented by Bnnn constant.

Fixes: 4516d50aabed ("serial: 8250: Use canary to restart console after suspend")
Signed-off-by: Pali Rohár <pali@...nel.org>
---
 drivers/tty/serial/8250/8250_port.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 39b35a61958c..441f317c55af 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -3314,8 +3314,13 @@ static void serial8250_console_restore(struct uart_8250_port *up)
 	unsigned int baud, quot, frac = 0;
 
 	termios.c_cflag = port->cons->cflag;
-	if (port->state->port.tty && termios.c_cflag == 0)
+	termios.c_ispeed = port->cons->ispeed;
+	termios.c_ospeed = port->cons->ospeed;
+	if (port->state->port.tty && termios.c_cflag == 0) {
 		termios.c_cflag = port->state->port.tty->termios.c_cflag;
+		termios.c_ispeed = port->state->port.tty->termios.c_ispeed;
+		termios.c_ospeed = port->state->port.tty->termios.c_ospeed;
+	}
 
 	baud = serial8250_get_baud_rate(port, &termios, NULL);
 	quot = serial8250_get_divisor(port, baud, &frac);
-- 
2.20.1