[PATCH 4.4 21/48] USB: serial: ch341: fix open and resume after B0

From: Greg Kroah-Hartman
Date: Wed Jan 18 2017 - 05:50:13 EST


4.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Johan Hovold <johan@xxxxxxxxxx>

commit a20047f36e2f6a1eea4f1fd261aaa55882369868 upstream.

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")
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/usb/serial/ch341.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -361,12 +361,11 @@ static void ch341_set_termios(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);