usbcore: check device's LPM capability

Check device's LPM capability by examining the bmAttibutes field of the
USB2.0 Extension Descriptor.
Signed-off-by: NAndiry Xu <andiry.xu@amd.com>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/hub.c

@@ -3083,8 +3083,14 @@ hub_port_init (struct usb_hub *hub, struct usb_device *udev, int port1,
 		goto fail;
 	}
 
-	if (udev->wusb == 0 && le16_to_cpu(udev->descriptor.bcdUSB) >= 0x0201)
-		usb_get_bos_descriptor(udev);
+	if (udev->wusb == 0 && le16_to_cpu(udev->descriptor.bcdUSB) >= 0x0201) {
+		retval = usb_get_bos_descriptor(udev);
+		if (!retval) {
+			if (udev->bos->ext_cap && (USB_LPM_SUPPORT &
+				le32_to_cpu(udev->bos->ext_cap->bmAttributes)))
+					udev->lpm_capable = 1;
+		}
+	}
 
 	retval = 0;
 	/* notify HCD that we have a device connected and addressed */

include/linux/usb.h

@@ -410,6 +410,7 @@ struct usb_tt;
  *	FIXME -- complete doc
  * @authenticated: Crypto authentication passed
  * @wusb: device is Wireless USB
+ * @lpm_capable: device supports LPM
  * @string_langid: language ID for strings
  * @product: iProduct string, if present (static)
  * @manufacturer: iManufacturer string, if present (static)
@@ -472,6 +473,7 @@ struct usb_device {
 	unsigned authorized:1;
 	unsigned authenticated:1;
 	unsigned wusb:1;
+	unsigned lpm_capable:1;
 	int string_langid;
 
 	/* static strings from the device */