1 files changed, 17 insertions, 3 deletions

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 81d19d5683ac..8284958fc530 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -1977,11 +1977,25 @@ static void __devinit quirk_via_cx700_pci_parking_caching(struct pci_dev *dev)
         /*
          * Disable PCI Bus Parking and PCI Master read caching on CX700
          * which causes unspecified timing errors with a VT6212L on the PCI
-         * bus leading to USB2.0 packet loss. The defaults are that these
-         * features are turned off but some BIOSes turn them on.
+         * bus leading to USB2.0 packet loss.
+         *
+         * This quirk is only enabled if a second (on the external PCI bus)
+         * VT6212L is found -- the CX700 core itself also contains a USB
+         * host controller with the same PCI ID as the VT6212L.
          */
 
+        /* Count VT6212L instances */
+        struct pci_dev *p = pci_get_device(PCI_VENDOR_ID_VIA,
+                PCI_DEVICE_ID_VIA_8235_USB_2, NULL);
         uint8_t b;
+
+        /* p should contain the first (internal) VT6212L -- see if we have
+           an external one by searching again */
+        p = pci_get_device(PCI_VENDOR_ID_VIA, PCI_DEVICE_ID_VIA_8235_USB_2, p);
+        if (!p)
+                return;
+        pci_dev_put(p);
+
         if (pci_read_config_byte(dev, 0x76, &b) == 0) {
                 if (b & 0x40) {
                         /* Turn off PCI Bus Parking */
@@ -2008,7 +2022,7 @@ static void __devinit quirk_via_cx700_pci_parking_caching(struct pci_dev *dev)
                 }
         }
 }
-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_VIA, 0x324e, quirk_via_cx700_pci_parking_caching);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_VIA, 0x324e, quirk_via_cx700_pci_parking_caching);
 
 /*
  * For Broadcom 5706, 5708, 5709 rev. A nics, any read beyond the