usbcore: set lpm_capable field for LPM capable root hubs

This patch sets the lpm_capable field for root hubs with LPM capabilities.
Signed-off-by: Xenia Ragiadakou <burzalodowa@gmail.com>
Reported-by: Martin MOKREJS <mmokrejs@gmail.com>
Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/core/hcd.c

@@ -1033,6 +1033,7 @@ static int register_root_hub(struct usb_hcd *hcd)
 					dev_name(&usb_dev->dev), retval);
 			return retval;
 		}
+		usb_dev->lpm_capable = usb_device_supports_lpm(usb_dev);
 	}
 
 	retval = usb_new_device (usb_dev);

drivers/usb/core/hub.c

@@ -135,7 +135,7 @@ struct usb_hub *usb_hub_to_struct_hub(struct usb_device *hdev)
 	return usb_get_intfdata(hdev->actconfig->interface[0]);
 }
 
-static int usb_device_supports_lpm(struct usb_device *udev)
+int usb_device_supports_lpm(struct usb_device *udev)
 {
 	/* USB 2.1 (and greater) devices indicate LPM support through
 	 * their USB 2.0 Extended Capabilities BOS descriptor.
@@ -156,6 +156,11 @@ static int usb_device_supports_lpm(struct usb_device *udev)
 				"Power management will be impacted.\n");
 		return 0;
 	}
+
+	/* udev is root hub */
+	if (!udev->parent)
+		return 1;
+
 	if (udev->parent->lpm_capable)
 		return 1;
 

drivers/usb/core/usb.h

@@ -35,6 +35,7 @@ extern int usb_get_device_descriptor(struct usb_device *dev,
 		unsigned int size);
 extern int usb_get_bos_descriptor(struct usb_device *dev);
 extern void usb_release_bos_descriptor(struct usb_device *dev);
+extern int usb_device_supports_lpm(struct usb_device *udev);
 extern char *usb_cache_string(struct usb_device *udev, int index);
 extern int usb_set_configuration(struct usb_device *dev, int configuration);
 extern int usb_choose_configuration(struct usb_device *udev);