xHCI bug fix for broken BIOS on some Intel systems.

Happy Valentine's Day!  Your present is a working xHCI driver under some
 Intel systems with buggy BIOSes that don't provide a legacy PCI IRQ line
 for the USB 3.0 host.
 
 Please queue for 3.3 and stable to share the love!
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Merge tag 'for-usb-linus-2012-02-14' of git://git.kernel.org/pub/scm/linux/kernel/git/sarah/xhci into usb-linus

xHCI bug fix for broken BIOS on some Intel systems.

Happy Valentine's Day!  Your present is a working xHCI driver under some
Intel systems with buggy BIOSes that don't provide a legacy PCI IRQ line
for the USB 3.0 host.

Please queue for 3.3 and stable to share the love!

drivers/usb/core/hcd-pci.c

@@ -187,7 +187,10 @@ int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 		return -ENODEV;
 	dev->current_state = PCI_D0;
 
-	if (!dev->irq) {
+	/* The xHCI driver supports MSI and MSI-X,
+	 * so don't fail if the BIOS doesn't provide a legacy IRQ.
+	 */
+	if (!dev->irq && (driver->flags & HCD_MASK) != HCD_USB3) {
 		dev_err(&dev->dev,
 			"Found HC with no IRQ.  Check BIOS/PCI %s setup!\n",
 			pci_name(dev));

drivers/usb/core/hcd.c

@@ -2447,8 +2447,10 @@ int usb_add_hcd(struct usb_hcd *hcd,
 			&& device_can_wakeup(&hcd->self.root_hub->dev))
 		dev_dbg(hcd->self.controller, "supports USB remote wakeup\n");
 
-	/* enable irqs just before we start the controller */
-	if (usb_hcd_is_primary_hcd(hcd)) {
+	/* enable irqs just before we start the controller,
+	 * if the BIOS provides legacy PCI irqs.
+	 */
+	if (usb_hcd_is_primary_hcd(hcd) && irqnum) {
 		retval = usb_hcd_request_irqs(hcd, irqnum, irqflags);
 		if (retval)
 			goto err_request_irq;

drivers/usb/host/xhci.c

@@ -352,6 +352,11 @@ static int xhci_try_enable_msi(struct usb_hcd *hcd)
 		/* hcd->irq is -1, we have MSI */
 		return 0;
 
+	if (!pdev->irq) {
+		xhci_err(xhci, "No msi-x/msi found and no IRQ in BIOS\n");
+		return -EINVAL;
+	}
+
 	/* fall back to legacy interrupt*/
 	ret = request_irq(pdev->irq, &usb_hcd_irq, IRQF_SHARED,
 			hcd->irq_descr, hcd);