Re: fixing "pci=use_crs"

[Yinghai Lu <yhlu.kernel@gmail.com>]

On Wed, Sep 23, 2009 at 8:21 PM, Bjorn Helgaas <bjorn.helgaas@hp.com> wrote:
> On Wed, 2009-09-23 at 16:28 -0700, Yinghai Lu wrote:
>> On Wed, Sep 23, 2009 at 4:23 PM, Bjorn Helgaas <bjorn.helgaas@hp.com> wrote:
>
>> > P.S.  Yinghai, you posted some patches earlier dealing with "only one
>> > HT chain."  You apparently have some insight into what's going on here,
>> > but unfortunately, the changelogs mean absolutely nothing to me.  Can
>> > you give me any clues?
>>
>> which commit?
>>
>> normally we only need to have split root resource into several pieces
>> when we have two HT chains or other io chains...
>
> I meant the patches here:
>  http://lkml.org/lkml/2009/6/24/557
>
> My opinion is that ACPI is there to give us an abstract description of
> the machine, and we shouldn't have to introduce knowledge like "this
> machine has two HT chains" or add checks in amd_bus.c about
> "pci_root_num <= 1".
>
> But maybe if I knew what an HT chain was and why you think it affects
> the description returned by _CRS, it would give me a clue about how to
> deal with this in a generic way.

we could use _CRS, but lots of BIOS just provide messed up resources
in _CRS to OS.

for example, the HW conf register does have mmio high range there, but
_CRS doesn't report them.

thought we can use whilelist to use _CRS for them.

YH