Re: [Qemu-devel] About hotplug multifunction

[Amos Kong <akong@redhat.com>]

Hi all,

After reading the pci driver code, I found a problem.

There is a list for each slot, (slot->funcs)
it will be inited in acpiphp_glue.c:register_slot() before hotpluging device,
and only one entry(func 0) will be added to it,
no new entry will be added to the list when hotpluging devices to the slot.

When we release the device, there are only _one_ entry in the list(slot->funcs).

acpiphp_glue.c:disable_device()
list_for_each_entry(func, &slot->funcs, sibling) {
    pdev = pci_get_slot(slot->bridge->pci_bus,
                        PCI_DEVFN(slot->device, func->function));
    ...release code...  // those code can only be executed one time (func 0)
    pci_remove_bus_device(pdev);
}

bus.c:pci_bus_add_device() is called for each func device in acpiphp_glue.c:enable_device().
bus.c:pci_remove_bus_device(pdev) is only called for func 0 in acpiphp_glue.c:disable_device().


Resolution: (I've tested it, success)
enumerate all the funcs when disable device.

list_for_each_entry(func, &slot->funcs, sibling) {
    for (i=0; i<8; i++) {
        pdev = pci_get_slot(slot->bridge->pci_bus,
                            PCI_DEVFN(slot->device, i));
        ...release code...
        pci_remove_bus_device(pdev);

    }
}

Thanks,
Amos