usbnet: Support devices reporting idleness

Some device types support a form of power management in which
the device suggests to the host that the device may be suspended
now. Support for that is best located in usbnet.

Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index fc9f578..f9819d1 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1588,10 +1588,27 @@
 			tasklet_schedule (&dev->bh);
 		}
 	}
+
+	if (test_and_clear_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags))
+		usb_autopm_get_interface_no_resume(intf);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(usbnet_resume);
 
+/*
+ * Either a subdriver implements manage_power, then it is assumed to always
+ * be ready to be suspended or it reports the readiness to be suspended
+ * explicitly
+ */
+void usbnet_device_suggests_idle(struct usbnet *dev)
+{
+	if (!test_and_set_bit(EVENT_DEVICE_REPORT_IDLE, &dev->flags)) {
+		dev->intf->needs_remote_wakeup = 1;
+		usb_autopm_put_interface_async(dev->intf);
+	}
+}
+EXPORT_SYMBOL(usbnet_device_suggests_idle);
 
 /*-------------------------------------------------------------------------*/