releases/3.4.95/usb-cdc-acm-fix-runtime-pm-for-control-messages.patch

From bae3f4c53585e9a170da9436e0f06919874bda9a Mon Sep 17 00:00:00 2001
From: Johan Hovold <jhovold@gmail.com>
Date: Mon, 26 May 2014 19:23:39 +0200
Subject: USB: cdc-acm: fix runtime PM for control messages

From: Johan Hovold <jhovold@gmail.com>

commit bae3f4c53585e9a170da9436e0f06919874bda9a upstream.

Fix runtime PM handling of control messages by adding the required PM
counter operations.

Fixes: 11ea859d64b6 ("USB: additional power savings for cdc-acm devices
that support remote wakeup")

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/class/cdc-acm.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -123,13 +123,23 @@ static void acm_release_minor(struct acm
 static int acm_ctrl_msg(struct acm *acm, int request, int value,
 							void *buf, int len)
 {
-	int retval = usb_control_msg(acm->dev, usb_sndctrlpipe(acm->dev, 0),
+	int retval;
+
+	retval = usb_autopm_get_interface(acm->control);
+	if (retval)
+		return retval;
+
+	retval = usb_control_msg(acm->dev, usb_sndctrlpipe(acm->dev, 0),
 		request, USB_RT_ACM, value,
 		acm->control->altsetting[0].desc.bInterfaceNumber,
 		buf, len, 5000);
+
 	dev_dbg(&acm->control->dev,
 			"%s - rq 0x%02x, val %#x, len %#x, result %d\n",
 			__func__, request, value, len, retval);
+
+	usb_autopm_put_interface(acm->control);
+
 	return retval < 0 ? retval : 0;
 }