USB: ch341: fix termios handling

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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 6b252ceb39a8..42582d49b69c 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -272,9 +272,6 @@ static void ch341_set_termios(struct usb_serial_port *port,
 
         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_serial_port *port,
          * (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 = {