usbcore: don't log on consecutive debounce failures of the same port

commit 5ee0f803 upstream.

Some laptops have an internal port for a BT device which picks
up noise when the kill switch is used, but not enough to trigger
printk_rlimit(). So we shouldn't log consecutive faults of this kind.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2:
 - Adjust context
 - Error message already includes the port number]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/usb/core/hub.c

@@ -3354,6 +3354,7 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
 			le16_to_cpu(hub->descriptor->wHubCharacteristics);
 	struct usb_device *udev;
 	int status, i;
+	static int unreliable_port = -1;
 
 	dev_dbg (hub_dev,
 		"port %d, status %04x, change %04x, %s\n",
@@ -3415,10 +3416,11 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
 				USB_PORT_STAT_C_ENABLE)) {
 		status = hub_port_debounce(hub, port1);
 		if (status < 0) {
-			if (printk_ratelimit())
+			if (port1 != unreliable_port && printk_ratelimit())
 				dev_err(hub_dev, "connect-debounce failed, "
 						"port %d disabled\n", port1);
 			portstatus &= ~USB_PORT_STAT_CONNECTION;
+			unreliable_port = port1;
 		} else {
 			portstatus = status;
 		}