Message-ID: <47D7D395.4070909@jp.fujitsu.com>
Date:	Wed, 12 Mar 2008 21:59:01 +0900
From:	Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>
To:	kristen.c.accardi@...el.com
CC:	Alex Chiang <achiang@...com>, Greg KH <gregkh@...e.de>,
	Jesse Barnes <jbarnes@...tuousgeek.org>,
	Matthew Wilcox <matthew@....cx>,
	Gary Hade <garyhade@...ibm.com>, warthog19@...lescrag.net,
	rick.jones2@...com, linux-kernel@...r.kernel.org,
	linux-pci@...ey.karlin.mff.cuni.cz, linux-acpi@...r.kernel.org
Subject: Re: [PATCH 4/4] ACPI PCI slot detection driver

Kristen Carlson Accardi wrote:
> On Tue, 11 Mar 2008 22:10:40 +0900
> Kenji Kaneshige <kaneshige.kenji@...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

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