[PATCH] USB: USB keyboard works after reboot (ehci-hcd)

This resolves a problem caused by "reboot" not actually
doing a clean shutdown of drivers.  It uses a reboot
notifier to make sure that typical BIOS code (using the
USB 1.1 companion controllers) will see keyboards even
without an EHCI driver being active.

drivers/usb/host/ehci-hcd.c

@@ -37,7 +37,7 @@
 #include <linux/timer.h>
 #include <linux/list.h>
 #include <linux/interrupt.h>
-
+#include <linux/reboot.h>
 #include <linux/usb.h>
 
 #include <linux/version.h>
@@ -306,6 +306,19 @@ static int bios_handoff (struct ehci_hcd *ehci, int where, u32 cap)
 	return 0;
 }
 
+static int
+ehci_reboot (struct notifier_block *self, unsigned long code, void *null)
+{
+	struct ehci_hcd		*ehci;
+
+	ehci = container_of (self, struct ehci_hcd, reboot_notifier);
+
+	/* make BIOS/etc use companion controller during reboot */
+	writel (0, &ehci->regs->configured_flag);
+	return 0;
+}
+
+
 /* called by khubd or root hub init threads */
 
 static int ehci_start (struct usb_hcd *hcd)
@@ -464,6 +477,9 @@ static int ehci_start (struct usb_hcd *hcd)
 	 * are explicitly handed to companion controller(s), so no TT is
 	 * involved with the root hub.
 	 */
+	ehci->reboot_notifier.notifier_call = ehci_reboot;
+	register_reboot_notifier (&ehci->reboot_notifier);
+
 	ehci->hcd.state = USB_STATE_READY;
 	writel (FLAG_CF, &ehci->regs->configured_flag);
 	readl (&ehci->regs->command);	/* unblock posted write */
@@ -520,6 +536,7 @@ static void ehci_stop (struct usb_hcd *hcd)
 
 	/* let companion controllers work when we aren't */
 	writel (0, &ehci->regs->configured_flag);
+	unregister_reboot_notifier (&ehci->reboot_notifier);
 
 	remove_debug_files (ehci);
 

drivers/usb/host/ehci.h

@@ -81,8 +81,10 @@ struct ehci_hcd {			/* one per controller */
 	struct pci_pool		*sitd_pool;	/* sitd per split iso urb */
 
 	struct timer_list	watchdog;
+	struct notifier_block	reboot_notifier;
 	unsigned		stamp;
 
+	/* irq statistics */
 #ifdef EHCI_STATS
 	struct ehci_stats	stats;
 #	define COUNT(x) do { (x)++; } while (0)