Re: [rfc] hw resource debugging checks

From: Yinghai Lu
Date: Sun Apr 13 2008 - 15:29:41 EST


On Sun, Apr 13, 2008 at 11:29 AM, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
> > even I could talk to BIOS
> > engineers everyday and tell them how to fix the problem in BIOS, some
> > still can not be fixed because of the legacy BIOS framework or big
> > mess.
>
> ... so you opt to create the big mess in the kernel. Great.
>
> And it does not even fixes a real problem, but getting
> mmconfig or the numa bus discovery to work is not really a too serious
> issue anyways. At best it is the icing on the cake to enable
> some relatively obscure functionality and be a little more
> efficient, but nothing really fundamental.
>
> But for those things just expecting a working modern BIOS is quite
> reasonable.

it does fix real problem. when big system with several HT links, and
every link some pcie slots.
you fully load pci-e cards (with pci bridge). BIOS will stop assign
io/mmio resource to left device if it run out of io port range.
(though it is supposed to go on to allocate mmio to left devices) (
modern pcie device only need mmio with drivers)

With pre set range allocation in NB pci conf, kernel could allocate
the resource in every peer root bus ranges.
(the code for assign resource to device that is not assigned resource
by BIOS --- already in kernel)

YH
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