USB: serial: cp210x: fix hardware flow-control disable

From: Konstantin Shkolnyy <[email protected]>

commit a377f9e906af4df9071ba8ddba60188cb4013d93 upstream

A bug in the CRTSCTS handling caused RTS to alternate between

CRTSCTS=0 => "RTS is transmit active signal" and CRTSCTS=1 => "RTS is used for receive flow control"

instead of

CRTSCTS=0 => "RTS is statically active" and CRTSCTS=1 => "RTS is used for receive flow control"

This only happened after first having enabled CRTSCTS.

---

This is a backport of an upstream fix to v4.4, which should apply too earlier stable trees as well.

Johan

 drivers/usb/serial/cp210x.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index a2b43a6e7fa7..c33dfff81cd3 100644
@@ -784,7 +784,7 @@ static void cp210x_set_termios(struct tty_struct *tty,
 		} else {
 			modem_ctl[0] &= ~0x7B;
 			modem_ctl[0] |= 0x01;
-			modem_ctl[1] |= 0x40;
+			modem_ctl[1] = 0x40;
 			dev_dbg(dev, "%s - flow control = NONE\n", __func__);
 		}
 

2.7.3