diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 0f75bd5..2a09aa5 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -734,7 +734,7 @@ void __devinit pci_process_bridge_OF_ranges(struct pci_controller *hose,
 			hose->io_base_virt = ioremap(cpu_addr, size);
 
 			/* Expect trouble if pci_addr is not 0 */
-			if (primary)
+			if (primary || !isa_io_base)
 				isa_io_base =
 					(unsigned long)hose->io_base_virt;
 #endif /* CONFIG_PPC32 */