ohci-pci: add qemu quirk

On a loaded virtualization host (dozen guests booting at the same time)
it may happen that the ohci controller emulation doesn't manage to do
timely frame processing, with the result that the io watchdog fires and
considers the controller being dead, even though it's only the emulation
being unusual slow due to the load peak.

So, add a quirk for qemu and don't use the watchdog in case we figure we
are running on emulated ohci.  The virtual ohci controller masquerades
as apple ohci controller, but we can identify it by subsystem id.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/host/ohci-pci.c

@@ -164,6 +164,15 @@ static int ohci_quirk_amd700(struct usb_hcd *hcd)
 	return 0;
 }
 
+static int ohci_quirk_qemu(struct usb_hcd *hcd)
+{
+	struct ohci_hcd *ohci = hcd_to_ohci(hcd);
+
+	ohci->flags |= OHCI_QUIRK_QEMU;
+	ohci_dbg(ohci, "enabled qemu quirk\n");
+	return 0;
+}
+
 /* List of quirks for OHCI */
 static const struct pci_device_id ohci_pci_quirks[] = {
 	{
@@ -214,6 +223,13 @@ static const struct pci_device_id ohci_pci_quirks[] = {
 		PCI_DEVICE(PCI_VENDOR_ID_ATI, 0x4399),
 		.driver_data = (unsigned long)ohci_quirk_amd700,
 	},
+	{
+		.vendor		= PCI_VENDOR_ID_APPLE,
+		.device		= 0x003f,
+		.subvendor	= PCI_SUBVENDOR_ID_REDHAT_QUMRANET,
+		.subdevice	= PCI_SUBDEVICE_ID_QEMU,
+		.driver_data	= (unsigned long)ohci_quirk_qemu,
+	},
 
 	/* FIXME for some of the early AMD 760 southbridges, OHCI
 	 * won't work at all.  blacklist them.