Re: SNB PCI root information

From: Yinghai Lu <yinghai@kernel.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	Ulrich Drepper <drepper@gmail.com>,
	jbarnes@virtuousgeek.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	lenb@kernel.org, x86@kernel.org, linux-pci@vger.kernel.org
Subject: Re: SNB PCI root information
Date: Wed, 20 Jun 2012 19:37:57 -0700	[thread overview]
Message-ID: <CAE9FiQWUo3uffM4NCUORJXR1pdPaf0E1Sws1hwVNAibHg5_yjQ@mail.gmail.com> (raw)
In-Reply-To: <20120620193438.GB2248@gmail.com>

On Wed, Jun 20, 2012 at 12:34 PM, Ingo Molnar <mingo@kernel.org> wrote:
>> if the vendor provide _PXM, that _PXM should be right and be
>> trusted.
>>
>> if the vendor does not provide _PXM, we can have command line
>> to input it before user can get one updated BIOS from vendor.
>
> So how about an incorrect _PXM, or a slightly inefficient one?
> Why shouldn't it be possible for the user to override it?

Try to keep the code simple.

>
> I mean, if we create a parameter space that tweaks data then why
> not make it complete and allow *all* firmware data to be
> (optionally) modified, from the kernel boot line?

that pxm/node for pci device should be consistent with srat table etc,
so better solution is that BIOS keep them consistent.

If BIOS provide _PXM for pci device, the _PXM should have more chance
to be right.

Anyway if you insist that it should cover that wrong case, let me
check if it could be done simply.

Thanks

Yinghai