commit de24e0a108bc48062e1c7acaa97014bce32a919f upstream. The current tiocmget implementation would fail to report errors up the stack and instead leaked a few bits from the stack as a mask of modem-status flags. Fixes: 39a66b8d22a3 ("[PATCH] USB: CP2101 Add support for flow control") Signed-off-by: Johan Hovold <johan@xxxxxxxxxx> --- Here's a backport of de24e0a108bc ("USB: serial: cp210x: fix tiocmget error handling") to 4.4. Johan drivers/usb/serial/cp210x.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c index 6eccded3bc33..976195e748a3 100644 --- a/drivers/usb/serial/cp210x.c +++ b/drivers/usb/serial/cp210x.c @@ -845,7 +845,9 @@ static int cp210x_tiocmget(struct tty_struct *tty) unsigned int control; int result; - cp210x_get_config(port, CP210X_GET_MDMSTS, &control, 1); + result = cp210x_get_config(port, CP210X_GET_MDMSTS, &control, 1); + if (result) + return result; result = ((control & CONTROL_DTR) ? TIOCM_DTR : 0) |((control & CONTROL_RTS) ? TIOCM_RTS : 0) -- 2.7.3 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html