From: Alan Cox <alan@lxorguk.ukuu.org.uk>

The ch341 currently doesn't support most of the hardware setting.  So to keep
the termios data right we propogate the old termios hardware values back then
encode the speed.

Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---


diff -puN drivers/usb/serial/ch341.c~ch341-fix-termios-handling drivers/usb/serial/ch341.c
--- a/drivers/usb/serial/ch341.c~ch341-fix-termios-handling
+++ a/drivers/usb/serial/ch341.c
@@ -272,9 +272,6 @@ static void ch341_set_termios(struct usb
 
 	dbg("ch341_set_termios()");
 
-	if (!tty || !tty->termios)
-		return;
-
 	baud_rate = tty_get_baud_rate(tty);
 
 	switch (baud_rate) {
@@ -299,6 +296,11 @@ static void ch341_set_termios(struct usb
 	 * (cflag & PARENB) : parity {NONE, EVEN, ODD}
 	 * (cflag & CSTOPB) : stop bits [1, 2]
 	 */
+
+	 /* Copy back the old hardware settings */
+	 tty_termios_copy_hw(tty->termios, old_termios);
+	 /* And re-encode with the new baud */
+	 tty_encode_baud_rate(tty, baud_rate, baud_rate);
 }
 
 static struct usb_driver ch341_driver = {
_