Re: [PATCH 2/3] PCI, ACPI: Don't glue ACPI dev with pci VFs

[Bjorn Helgaas <bhelgaas@google.com>]

On Fri, May 31, 2013 at 3:40 PM, Bjorn Helgaas <bhelgaas@google.com> wrote:
> [+cc Rafael]
>
> On Thu, May 30, 2013 at 10:21 PM, Jiang Liu <liuj97@gmail.com> wrote:
>> From: Yinghai Lu <yinghai@kernel.org>
>>
>> When sriov is enabled, VF could just start after PF in pci tree.
>> like c1:00.0 will be PF, and c1:00.1 and after will be VF.
>>
>> acpi do have dev with same ADR. that will make them get glued
>> wrongly.
>>
>> Skip that if it is virtfn.
>>
>> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
>> Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
>> ---
>>  drivers/pci/pci-acpi.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
>> index e4b1fb2..720f3a2 100644
>> --- a/drivers/pci/pci-acpi.c
>> +++ b/drivers/pci/pci-acpi.c
>> @@ -321,6 +321,10 @@ static int acpi_pci_find_device(struct device *dev, acpi_handle *handle)
>>         u64     addr;
>>
>>         pci_dev = to_pci_dev(dev);
>> +       /* don't mix vf with real pci device */
>> +       if (pci_dev->is_virtfn)
>> +               return -ENODEV;
>
> Rafael, can you review this?  I don't understand the implications of
> this change.
>
> And I don't know exactly what problem this would fix, so I don't know
> if it's stable material or not.  Yinghai did propose it as v3.10
> material in https://lkml.kernel.org/r/1368498506-25857-1-git-send-email-yinghai@kernel.org,
> but I don't know why.

Ping?

Jiang or Yinghai, what problem does this fix?

I'm guessing maybe all three of these should be marked for stable, but
I'd like confirmation of that.

>>         /* Please ref to ACPI spec for the syntax of _ADR */
>>         addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn);
>>         *handle = acpi_get_child(DEVICE_ACPI_HANDLE(dev->parent), addr);
>> --
>> 1.8.1.2
>>