Only wake up MSR wait queue on actual modem-status changes. Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx> --- drivers/usb/serial/ch341.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c index 025b7857a36c..acc88650ac0a 100644 --- a/drivers/usb/serial/ch341.c +++ b/drivers/usb/serial/ch341.c @@ -460,6 +460,9 @@ static void ch341_update_line_status(struct usb_serial_port *port, if (data[1] & CH341_MULT_STAT) dev_dbg(&port->dev, "%s - multiple status change\n", __func__); + if (!delta) + return; + if (delta & CH341_BIT_DCD) { tty = tty_port_tty_get(&port->port); if (tty) { -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html