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

[ Upstream commit a20047f36e2f6a1eea4f1fd261aaa55882369868 ]

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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 2df74c018b55b29c4469561b3676ce93be12e734..ddb05ee0762b34b799f274de94b81c6e8f5d3fc7 100644 (file)
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -344,12 +344,11 @@ static void ch341_set_termios(struct tty_struct *tty,
 
        baud_rate = tty_get_baud_rate(tty);
 
-       priv->baud_rate = baud_rate;
-
        if (baud_rate) {
                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;
                ch341_set_baudrate(port->serial->dev, priv);
        } else {
                spin_lock_irqsave(&priv->lock, flags);