Commit 12f44f46 authored by Ivan Kokshaysky's avatar Ivan Kokshaysky Committed by Linus Torvalds
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[PATCH] pci: fixup parent subordinate busnr

I believe the change that broke things is introduction of

The patch here does two things:
- hunk #1 should fix the problems you've seen when you boot without
  additional "pci" kernel options;
- hunk #2 supposedly fixes boot with "pci=assign-busses" option which
  otherwise hangs Acer TM81xx machines as reported.

Please try this with and without "pci=assign-busses". If it boots,
I'd like to see 'lspci -vvx' for both cases.
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent bfab08c0
......@@ -402,6 +402,12 @@ static void pci_enable_crs(struct pci_dev *dev)
static void __devinit pci_fixup_parent_subordinate_busnr(struct pci_bus *child, int max)
struct pci_bus *parent = child->parent;
/* Attempts to fix that up are really dangerous unless
we're going to re-assign all bus numbers. */
if (!pcibios_assign_all_busses())
while (parent->parent && parent->subordinate < max) {
parent->subordinate = max;
pci_write_config_byte(parent->self, PCI_SUBORDINATE_BUS, max);
......@@ -478,8 +484,18 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max
* We need to assign a number to this bus which we always
* do in the second pass.
if (!pass)
if (!pass) {
if (pcibios_assign_all_busses())
/* Temporarily disable forwarding of the
configuration cycles on all bridges in
this bus segment to avoid possible
conflicts in the second pass between two
bridges programmed with overlapping
bus ranges. */
pci_write_config_dword(dev, PCI_PRIMARY_BUS,
buses & ~0xffffff);
return max;
/* Clear errors */
pci_write_config_word(dev, PCI_STATUS, 0xffff);
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