[PATCH] USB: central handling for host controllers that were reset during suspend/resume

This patch (as515b) adds a routine to usbcore to simplify handling of
host controllers that lost power or were reset during suspend/resume.
The new core routine marks all the child devices of the root hub as
NOTATTACHED and tells khubd to disconnect the device structures as soon
as possible.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

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

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;

drivers/usb/host/ehci-pci.c

@@ -278,7 +278,6 @@ static int ehci_pci_resume(struct usb_hcd *hcd)
 {
 	struct ehci_hcd		*ehci = hcd_to_ehci(hcd);
 	unsigned		port;
-	struct usb_device	*root = hcd->self.root_hub;
 	struct pci_dev		*pdev = to_pci_dev(hcd->self.controller);
 	int			retval = -EINVAL;
 
@@ -312,13 +311,7 @@ static int ehci_pci_resume(struct usb_hcd *hcd)
 
 restart:
 	ehci_dbg(ehci, "lost power, restarting\n");
-	for (port = HCS_N_PORTS(ehci->hcs_params); port > 0; ) {
-		port--;
-		if (!root->children [port])
-			continue;
-		usb_set_device_state(root->children[port],
-					USB_STATE_NOTATTACHED);
-	}
+	usb_root_hub_lost_power(hcd->self.root_hub);
 
 	/* Else reset, to cope with power loss or flush-to-storage
 	 * style "resume" having let BIOS kick in during reboot.

drivers/usb/host/ohci-hcd.c

@@ -795,7 +795,6 @@ static int ohci_restart (struct ohci_hcd *ohci)
 	int temp;
 	int i;
 	struct urb_priv *priv;
-	struct usb_device *root = ohci_to_hcd(ohci)->self.root_hub;
 
 	/* mark any devices gone, so they do nothing till khubd disconnects.
 	 * recycle any "live" eds/tds (and urbs) right away.
@@ -804,11 +803,7 @@ static int ohci_restart (struct ohci_hcd *ohci)
 	 */ 
 	spin_lock_irq(&ohci->lock);
 	disable (ohci);
-	for (i = 0; i < root->maxchild; i++) {
-		if (root->children [i])
-			usb_set_device_state (root->children[i],
-				USB_STATE_NOTATTACHED);
-	}
+	usb_root_hub_lost_power(ohci_to_hcd(ohci)->self.root_hub);
 	if (!list_empty (&ohci->pending))
 		ohci_dbg(ohci, "abort schedule...\n");
 	list_for_each_entry (priv, &ohci->pending, pending) {

drivers/usb/host/sl811-hcd.c

@@ -1803,6 +1803,7 @@ sl811h_resume(struct platform_device *dev)
 			|| !device_can_wakeup(&hcd->self.root_hub->dev)) {
 		sl811->port1 = 0;
 		port_power(sl811, 1);
+		usb_root_hub_lost_power(hcd->self.root_hub);
 		return 0;
 	}
 

drivers/usb/host/uhci-hcd.c

@@ -748,8 +748,12 @@ static int uhci_resume(struct usb_hcd *hcd)
 	check_and_reset_hc(uhci);
 	configure_hc(uhci);
 
-	if (uhci->rh_state == UHCI_RH_RESET)
+	if (uhci->rh_state == UHCI_RH_RESET) {
+
+		/* The controller had to be reset */
+		usb_root_hub_lost_power(hcd->self.root_hub);
 		suspend_rh(uhci, UHCI_RH_SUSPENDED);
+	}
 
 	spin_unlock_irq(&uhci->lock);