Commit 12c22d6e authored by Linus Torvalds's avatar Linus Torvalds

Revert "PCI: remove transparent bridge sizing"

This reverts commit 8fa5913d, which
caused various interesting problems for people, including wrong resource
allocations.  See for example bugzilla entry "2.6.25-rc2: ohci1394
problem (MMIO broken)" at

	http://bugzilla.kernel.org/show_bug.cgi?id=10080

And Gary Hade says:

 "The same change had also exposed an issue reported by Paul Martin that
  has been causing an Oops while hotplugging ThinkPads to a ThinkPad
  Dock II.  See

	http://lkml.org/lkml/2008/2/19/405
	http://bugzilla.kernel.org/show_bug.cgi?id=9961

  I have a fix for the ThinkPad docking Oops but if the issue being
  discussed here is caused by the transparent bridge sizing removal
  change I totally agree that it should be reverted."

  The transparent bridge sizing removal change was motivated by
  insufficient PCI memory resource for a transparent bridge window that
  was being created as a result of expansion ROM(s) being included in
  the transparent bridge sizing calculations.

  A later "PCI: Remove default PCI expansion ROM memory allocation"
  change ( re: http://lkml.org/lkml/2007/12/11/361 ) removes the
  expansion ROM(s) from the transparent bridge sizing calculations which
  actually resolves the original issue in a different manner.  So, even
  if the "PCI: remove transparent bridge sizing" is not problematic it
  is no longer needed anyway."
Identified-by: default avatarIvan Kokshaysky <ink@jurassic.park.msu.ru>
Tested-by: default avatarThomas Meyer <thomas@m3y3r.de>
Acked-by: default avatarGary Hade <garyhade@us.ibm.com>
Acked-by: default avatarIngo Molnar <mingo@elte.hu>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 05dda977
...@@ -486,12 +486,7 @@ void __ref pci_bus_size_bridges(struct pci_bus *bus) ...@@ -486,12 +486,7 @@ void __ref pci_bus_size_bridges(struct pci_bus *bus)
break; break;
case PCI_CLASS_BRIDGE_PCI: case PCI_CLASS_BRIDGE_PCI:
/* don't size subtractive decoding (transparent)
* PCI-to-PCI bridges */
if (bus->self->transparent)
break;
pci_bridge_check_ranges(bus); pci_bridge_check_ranges(bus);
/* fall through */
default: default:
pbus_size_io(bus); pbus_size_io(bus);
/* If the bridge supports prefetchable range, size it /* If the bridge supports prefetchable range, size it
......
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