diff --git a/arch/microblaze/pci/pci-common.c b/arch/microblaze/pci/pci-common.c
index 9cb782b8e036..23be25fec4d6 100644
--- a/arch/microblaze/pci/pci-common.c
+++ b/arch/microblaze/pci/pci-common.c
@@ -1277,6 +1277,7 @@ void pcibios_allocate_bus_resources(struct pci_bus *bus)
 		printk(KERN_WARNING "PCI: Cannot allocate resource region "
 		       "%d of PCI bridge %d, will remap\n", i, bus->number);
 clear_resource:
+		res->start = res->end = 0;
 		res->flags = 0;
 	}
 
diff --git a/arch/mn10300/unit-asb2305/pci-asb2305.c b/arch/mn10300/unit-asb2305/pci-asb2305.c
index d6119b879a98..45b40ac6c464 100644
--- a/arch/mn10300/unit-asb2305/pci-asb2305.c
+++ b/arch/mn10300/unit-asb2305/pci-asb2305.c
@@ -117,6 +117,7 @@ static void __init pcibios_allocate_bus_resources(struct list_head *bus_list)
 					 * Invalidate the resource to prevent
 					 * child resource allocations in this
 					 * range. */
+					r->start = r->end = 0;
 					r->flags = 0;
 				}
 			}
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 6646005dffb1..5b38f6ae2b29 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -1309,6 +1309,7 @@ void pcibios_allocate_bus_resources(struct pci_bus *bus)
 		printk(KERN_WARNING "PCI: Cannot allocate resource region "
 		       "%d of PCI bridge %d, will remap\n", i, bus->number);
 clear_resource:
+		res->start = res->end = 0;
 		res->flags = 0;
 	}
 
diff --git a/arch/x86/pci/i386.c b/arch/x86/pci/i386.c
index 97da2ba9344b..6fdb3ec30c31 100644
--- a/arch/x86/pci/i386.c
+++ b/arch/x86/pci/i386.c
@@ -96,6 +96,7 @@ EXPORT_SYMBOL(pcibios_align_resource);
  *	  the fact the PCI specs explicitly allow address decoders to be
  *	  shared between expansion ROMs and other resource regions, it's
  *	  at least dangerous)
+ *	- bad resource sizes or overlaps with other regions
  *
  *  Our solution:
  *	(1) Allocate resources for all buses behind PCI-to-PCI bridges.
@@ -136,6 +137,7 @@ static void __init pcibios_allocate_bus_resources(struct list_head *bus_list)
 					 * child resource allocations in this
 					 * range.
 					 */
+					r->start = r->end = 0;
 					r->flags = 0;
 				}
 			}