USB: serial: ch341: fix open and resume after B0

The private baud_rate variable is used to configure the port at open and
reset-resume and must never be set to (and left at) zero or reset-resume
and all further open attempts will fail.

Fixes: aa91def41a7b ("USB: ch341: set tty baud speed according to tty
struct")
Fixes: 664d5df92e88 ("USB: usb-serial ch341: support for DTR/RTS/CTS")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index d133e72fe888..6279df905c14 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -355,7 +355,6 @@ static void ch341_set_termios(struct tty_struct *tty,
 
         baud_rate = tty_get_baud_rate(tty);
 
-        priv->baud_rate = baud_rate;
         ctrl = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX;
 
         switch (C_CSIZE(tty)) {
@@ -388,6 +387,9 @@ static void ch341_set_termios(struct tty_struct *tty,
                 spin_lock_irqsave(&priv->lock, flags);
                 priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS);
                 spin_unlock_irqrestore(&priv->lock, flags);
+
+                priv->baud_rate = baud_rate;
+
                 r = ch341_init_set_baudrate(port->serial->dev, priv, ctrl);
                 if (r < 0 && old_termios) {
                         priv->baud_rate = tty_termios_baud_rate(old_termios);