usbnet & cdc-ether: Autosuspend for online devices

Using remote wakeup and delayed transmission to allow
online device to go into usb autosuspend.
Minimal alternate support for devices that don't support
remote wakeup.

Signed-off-by: Oliver Neukum <oliver@neukum.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/usb/cdc_ether.c b/drivers/net/usb/cdc_ether.c
index 197912d..21e183a 100644
--- a/drivers/net/usb/cdc_ether.c
+++ b/drivers/net/usb/cdc_ether.c
@@ -411,6 +411,12 @@
 	return 0;
 }
 
+static int cdc_manage_power(struct usbnet *dev, int on)
+{
+	dev->intf->needs_remote_wakeup = on;
+	return 0;
+}
+
 static const struct driver_info	cdc_info = {
 	.description =	"CDC Ethernet Device",
 	.flags =	FLAG_ETHER | FLAG_LINK_INTR,
@@ -418,6 +424,7 @@
 	.bind =		cdc_bind,
 	.unbind =	usbnet_cdc_unbind,
 	.status =	cdc_status,
+	.manage_power =	cdc_manage_power,
 };
 
 static const struct driver_info mbm_info = {
@@ -619,6 +626,7 @@
 	.suspend =	usbnet_suspend,
 	.resume =	usbnet_resume,
 	.reset_resume =	usbnet_resume,
+	.supports_autosuspend = 1,
 };