From stable-bounces@linux.kernel.org Thu Jul 19 20:46:46 2007
From: Alan Stern <stern@rowland.harvard.edu>
Date: Thu, 19 Jul 2007 20:44:51 -0700
Subject: USB: fix warning caused by autosuspend counter going negative
To: linux-usb-devel@lists.sourceforge.net
Cc: Greg Kroah-Hartman <gregkh@suse.de>, Alan Stern <stern@rowland.harvard.edu>
Message-ID: <1184903162294-git-send-email-gregkh@suse.de>


From: Alan Stern <stern@rowland.harvard.edu>

This patch (as937) fixes a minor bug in the autosuspend usage-counting
code.  Each hub's usage counter keeps track of the number of
unsuspended children.  However the current driver increments the
counter after registering a new child, by which time the child may
already have been suspended and caused the counter to go negative.
The obvious solution is to increment the counter before registering
the child.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 drivers/usb/core/hub.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1388,6 +1388,10 @@ int usb_new_device(struct usb_device *ud
 	udev->dev.devt = MKDEV(USB_DEVICE_MAJOR,
 			(((udev->bus->busnum-1) * 128) + (udev->devnum-1)));
 
+	/* Increment the parent's count of unsuspended children */
+	if (udev->parent)
+		usb_autoresume_device(udev->parent);
+
 	/* Register the device.  The device driver is responsible
 	 * for adding the device files to sysfs and for configuring
 	 * the device.
@@ -1395,13 +1399,11 @@ int usb_new_device(struct usb_device *ud
 	err = device_add(&udev->dev);
 	if (err) {
 		dev_err(&udev->dev, "can't device_add, error %d\n", err);
+		if (udev->parent)
+			usb_autosuspend_device(udev->parent);
 		goto fail;
 	}
 
-	/* Increment the parent's count of unsuspended children */
-	if (udev->parent)
-		usb_autoresume_device(udev->parent);
-
 exit:
 	return err;