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

From: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
To: Alex Chiang <achiang@hp.com>,
	Kristen Carlson Accardi <kristen.c.accardi@intel.com>,
	Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>,
	Greg KH <gregkh@suse.de>, Jesse Barnes <jbarnes@virtuousgeek.org>,
	Matthew Wilcox <matthew@wil.cx>, Gary Hade <garyhade@us.ibm.com>,
	warthog19@eaglescrag.net, rick.jones2@hp.com,
	linux-kernel@vger.kernel.org, linux-pci@atrey.karlin.mff.cuni.cz,
	linux-acpi@vger.kernel.org
Subject: Re: [PATCH 4/4] ACPI PCI slot detection driver
Date: Wed, 12 Mar 2008 20:33:00 +0900	[thread overview]
Message-ID: <47D7BF6C.3080306@jp.fujitsu.com> (raw)
In-Reply-To: <20080311191406.GB29344@ldl.fc.hp.com>

Hi Alex-san,

> On my machine, it is legal to evaluate S1F0._SUN independent of
> S1F0._STA because L001._INI has already been evaluated.
> 
> It would be helpful to know what Fujitsu's namespace looks like.
> If Fujitsu slot objects contain _STA and _INI, then I agree with
> Kenji-san -- I definitely need to check _STA before evaluating
> _SUN.

Thank you for explanation. Maybe I understood the summary of
implementation of HP firmware. But how to use or where to put _INI
method in the ACPI namespace never becomes reasonable reason why
your driver may ignore _STA before evaluating _SUN.

> But in any case, I think both HP and Fujitsu firmware are doing
> legal things -- neither firmware is breaking the spec.

My understanding of your explanation so far is:

- evaluating _SUN without checking _STA doesn't cause problem,
  from the view point of HP's implementation.
- some IBM machine is doing same as HP

I never think those are reasonable reasons why ignoring _STA
before evaluating _SUN is legal. Am I missing something?

> If one list is shorter than the other, then that should be the
> list to put in the kernel, and the default behavior should be
> "majority rule".

I don't want to consider "majority rule" before I understand why
ignoring _STA is legal.

Thanks,
Kenji Kaneshige