USB: ch341: only wake up MSR queue on changes
Only wake up MSR wait queue on actual modem-status changes.
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 025b785..acc8865 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -460,6 +460,9 @@
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) {