drivers/pci/probe.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index b1724cf..e3c3ee0 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1002,11 +1002,21 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
 struct pci_dev *__ref pci_scan_single_device(struct pci_bus *bus, int devfn)
 {
 	struct pci_dev *dev;
+	struct list_head *ln;
 
 	dev = pci_scan_device(bus, devfn);
 	if (!dev)
 		return NULL;
 
+	/* refuse to re-add a device */
+	list_for_each(ln, &bus->devices) {
+		struct pci_dev *d = pci_dev_b(ln);
+		if ((d->vendor == dev->vendor) &&
+		    (d->device == dev->device) &&
+		    (d->devfn == dev->devfn))
+			return NULL;
+	}
+
 	pci_device_add(dev, bus);
 
 	return dev;