Re: [PATCH 4/4] ACPI PCI slot detection driver

Kenji Kaneshige
2008-03-12T13:00:16Z

Kristen Carlson Accardi wrote:
> On Tue, 11 Mar 2008 22:10:40 +0900
> Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> wrote:
>
>> Hi Alex-san,
>>
>> I tried your patches, and I have two comments. I want 1) to be fixed
>> before merge to Greg's tree (or linux-next?), at least.
>
> yes, we will not merge these patches without your ack.
>
>> 1) I checked ACPI spec again and again, but I could not find any
>> reason to add Fujitsu servers to quirks list. So I'd like you to
>> add HP servers to the quirks list. I'll send the following patches
>> followed by this e-mail.
>
> I have followed up with a question on this on another thread, so I'll
> skip to #2...
> <snip>
>
>> 2) The ACPI PCI slot detection driver would change the slot names of
>> some hotplug drivers (at least I checked shpchp and pciehp). And
>> the name of slots are depending on the order of driver loading.
>> For example, on my system which has several SHPCHP slots and
>> PCIEHP slots, the name of PCIEHP slots are changed as
>> follows. Please note that PCIEHP based slots are 0034_0027 and
>> 0032_0026, and others are SHPCHP based slots.
>>
>> - Without ACPI PCI slot detection driver
>> # ls /sys/bus/pci/slots/
>> 0009_0016 0014_0018 0019_0020 0021_0022 0034_0027
>> 0011_0017 0016_0019 0021_0021 0032_0026
>>
>> - With ACPI PCI slot detection driver
>> # ls /sys/bus/pci/slots/
>> 0009_0016 0014_0018 0019_0020 0021_0022 27
>> 0011_0017 0016_0019 0021_0021 26
>>
>> I had thought it is not a big problem before because people who
>> don't like new names would not load the PCI slot driver. But since
>> it is loaded automatically at boot time, I'm wondering that it
>> would be a problem. For example, some platform, not fujitsu,
>> depends on the old slot name to work, IIRC (Maybe Kristen knows
>> the background about it). And I don't think the fact that slot
>> names are changed depending on the order of driver loading is
>> acceptable by system management people/software, though I don't
>> have such software.
>>
>> Though I don't have any specific idea about this, folliwings might
>> be candidates.
>>
>> - Override slot names with hotplug driver's slot names
>
> I think this should be done - if the pci slot driver detects that a
> hotplug driver is controlling a slot, it should allow that driver to
> set the name of the slot.
>

Yes, it is what I thought.
But maybe we should try unifying slots names first, I think.

>> - Unify slot names among all hotplug drivers
>
> I'm not sure if we can do this, since slot name might depend on what
> spec people are implementing.
>

I'm not sure too. But I think we can unify the slot names using the
combination of chassis number and slot number among the controllers
which is based on PCI Hot-Plug spec.

>> - Stop automatic loading of ACPI PCI slot driver
>
> I think we should definitely implement this one ^^^.
>

Yes. It's the simplest workaround.

BTW, I'll be out of office tomorrow. So replying to this discussion
will be delayed. I'm sorry about that.

Thanks,
Kenji Kaneshige