2 files changed, 34 insertions, 0 deletions

diff --git a/drivers/usb/core/hcd.h b/drivers/usb/core/hcd.h
index c8a1b350e2c..591b5aad1a1 100644
--- a/drivers/usb/core/hcd.h
+++ b/drivers/usb/core/hcd.h
@@ -380,6 +380,7 @@ extern int usb_find_interface_driver (struct usb_device *dev,
 #ifdef CONFIG_PM
 extern void usb_hcd_suspend_root_hub (struct usb_hcd *hcd);
 extern void usb_hcd_resume_root_hub (struct usb_hcd *hcd);
+extern void usb_root_hub_lost_power (struct usb_device *rhdev);
 extern int hcd_bus_suspend (struct usb_bus *bus);
 extern int hcd_bus_resume (struct usb_bus *bus);
 #else
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index f78bd124d29..5faf7edd73c 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1039,6 +1039,39 @@ void usb_set_device_state(struct usb_device *udev,
 EXPORT_SYMBOL(usb_set_device_state);
 
 
+#ifdef CONFIG_PM
+
+/**
+ * usb_root_hub_lost_power - called by HCD if the root hub lost Vbus power
+ * @rhdev: struct usb_device for the root hub
+ *
+ * The USB host controller driver calls this function when its root hub
+ * is resumed and Vbus power has been interrupted or the controller
+ * has been reset.  The routine marks all the children of the root hub
+ * as NOTATTACHED and marks logical connect-change events on their ports.
+ */
+void usb_root_hub_lost_power(struct usb_device *rhdev)
+{
+        struct usb_hub *hub;
+        int port1;
+        unsigned long flags;
+
+        dev_warn(&rhdev->dev, "root hub lost power or was reset\n");
+        spin_lock_irqsave(&device_state_lock, flags);
+        hub = hdev_to_hub(rhdev);
+        for (port1 = 1; port1 <= rhdev->maxchild; ++port1) {
+                if (rhdev->children[port1 - 1]) {
+                        recursively_mark_NOTATTACHED(
+                                        rhdev->children[port1 - 1]);
+                        set_bit(port1, hub->change_bits);
+                }
+        }
+        spin_unlock_irqrestore(&device_state_lock, flags);
+}
+EXPORT_SYMBOL_GPL(usb_root_hub_lost_power);
+
+#endif
+
 static void choose_address(struct usb_device *udev)
 {
         int             devnum;