Only the first UART interface (ECI) on CP2105 supports break signalling. Return an error on requests for break state changes for the second interface (SCI) to avoid transmitting a garbage character and waiting when break is not supported. Signed-off-by: Johan Hovold <johan@xxxxxxxxxx> --- drivers/usb/serial/cp210x.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c index 81e49ed9d147..1e61fe043171 100644 --- a/drivers/usb/serial/cp210x.c +++ b/drivers/usb/serial/cp210x.c @@ -1437,8 +1437,14 @@ static int cp210x_tiocmget(struct tty_struct *tty) static int cp210x_break_ctl(struct tty_struct *tty, int break_state) { struct usb_serial_port *port = tty->driver_data; + struct cp210x_serial_private *priv = usb_get_serial_data(port->serial); u16 state; + if (priv->partnum == CP210X_PARTNUM_CP2105) { + if (cp210x_interface_num(port->serial) == 1) + return -ENOTTY; + } + if (break_state == 0) state = BREAK_OFF; else -- 2.39.3