PCI: clear bridge resource range if BIOS assigned bad one

Yannick found that video does not work with 2.6.34.  The cause of this
bug was that the BIOS had assigned the wrong range to the PCI bridge
above the video device.  Before 2.6.34 the kernel would have shrunk
the size of the bridge window, but since
  d65245c PCI: don't shrink bridge resources
the kernel will avoid shrinking BIOS ranges.

So zero out the old range if we fail to claim it at boot time; this will
cause us to allocate a new range at startup, restoring the 2.6.34
behavior.

Fixes regression https://bugzilla.kernel.org/show_bug.cgi?id=16009.

Reported-by: Yannick <yannick.roehlly@free.fr>
Acked-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

4 files changed, 5 insertions, 0 deletions

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;
 				}
 			}