From: Rajesh Shah When hot-plugging a root bridge, as we try to assign bus numbers we may find that the hotplugged hieratchy has more PCI to PCI bridges (i.e. bus requirements) than available. Make sure we don't step over an existing bus when that happens. Signed-off-by: Rajesh Shah Signed-off-by: Andrew Morton --- drivers/pci/probe.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-) diff -puN drivers/pci/probe.c~acpi-bridge-hotadd-prevent-duplicate-bus-numbers-when-scanning-pci-bridge drivers/pci/probe.c --- 25/drivers/pci/probe.c~acpi-bridge-hotadd-prevent-duplicate-bus-numbers-when-scanning-pci-bridge 2005-04-28 00:24:29.552385832 -0700 +++ 25-akpm/drivers/pci/probe.c 2005-04-28 00:24:29.555385376 -0700 @@ -407,7 +407,7 @@ int __devinit pci_scan_bridge(struct pci { struct pci_bus *child; int is_cardbus = (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS); - u32 buses; + u32 buses, i; u16 bctl; pci_read_config_dword(dev, PCI_PRIMARY_BUS, &buses); @@ -466,6 +466,10 @@ int __devinit pci_scan_bridge(struct pci /* Clear errors */ pci_write_config_word(dev, PCI_STATUS, 0xffff); + /* Prevent assigning a bus number that already exists. + * This can happen when a bridge is hot-plugged */ + if (pci_find_bus(pci_domain_nr(bus), max+1)) + return max; child = pci_alloc_child_bus(bus, dev, ++max); buses = (buses & 0xff000000) | ((unsigned int)(child->primary) << 0) @@ -497,7 +501,11 @@ int __devinit pci_scan_bridge(struct pci * as cards with a PCI-to-PCI bridge can be * inserted later. */ - max += CARDBUS_RESERVE_BUSNR; + for (i=0; i