diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index c77d5b1bbff6..005786416bb5 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -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()) + return; + 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);