From d984fe91a85e49841449b120cda5a50fed1fb126 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Thu, 2 Jan 2014 22:49:31 +0100 Subject: [PATCH] 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 Signed-off-by: Greg Kroah-Hartman --- 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 025b785..acc8865 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) { -- 2.7.4