xhci: clear root port wake on bits if controller isn't wake-up capable

commit ff8cbf25 upstream.

When xHCI PCI host is suspended, if do_wakeup is false in xhci_pci_suspend,
xhci_bus_suspend needs to clear all root port wake on bits. Otherwise some Intel
platforms may get a spurious wakeup, even if PCI PME# is disabled.

This patch should be back-ported to kernels as old as 2.6.37, that
contains the commit 9777e3ce
"USB: xHCI: bus power management implementation".
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/usb/host/xhci-hub.c

@@ -21,6 +21,7 @@
  */
 
 #include <linux/gfp.h>
+#include <linux/device.h>
 #include <asm/unaligned.h>
 
 #include "xhci.h"
@@ -993,7 +994,9 @@ int xhci_bus_suspend(struct usb_hcd *hcd)
 			t2 |= PORT_LINK_STROBE | XDEV_U3;
 			set_bit(port_index, &bus_state->bus_suspended);
 		}
-		if (hcd->self.root_hub->do_remote_wakeup) {
+		if (hcd->self.root_hub->do_remote_wakeup
+				&& device_may_wakeup(hcd->self.controller)) {
+
 			if (t1 & PORT_CONNECT) {
 				t2 |= PORT_WKOC_E | PORT_WKDISC_E;
 				t2 &= ~PORT_WKCONN_E;