diff --git a/arch/x86/pci/mrst.c b/arch/x86/pci/mrst.c
index 8bf2fcb..1cdc02c 100644
--- a/arch/x86/pci/mrst.c
+++ b/arch/x86/pci/mrst.c
@@ -247,6 +247,10 @@ static void __devinit pci_fixed_bar_fixup(struct pci_dev *dev)
 	u32 size;
 	int i;
 
+	/* Must have extended configuration space */
+	if (dev->cfg_size < PCIE_CAP_OFFSET + 4)
+		return;
+
 	/* Fixup the BAR sizes for fixed BAR devices and make them unmoveable */
 	offset = fixed_bar_cap(dev->bus, dev->devfn);
 	if (!offset || PCI_DEVFN(2, 0) == dev->devfn ||