linux-kernel - Re: [RFC PATCH] PCI MMCONFIG: add validation against ACPI motherboard resources

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Date:	Wed, 02 May 2007 17:45:32 -0600
From:	Robert Hancock <hancockr@...w.ca>
To:	Jesse Barnes <jbarnes@...tuousgeek.org>
Cc:	Olivier Galibert <galibert@...ox.com>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Andi Kleen <ak@...e.de>, Chuck Ebbert <cebbert@...hat.com>,
	Len Brown <lenb@...nel.org>
Subject: Re: [RFC PATCH] PCI MMCONFIG: add validation against ACPI motherboard
 resources

Jesse Barnes wrote:
> On Wednesday, May 2, 2007 7:34 am Robert Hancock wrote:
>> Jesse Barnes wrote:
>>> On Tuesday, May 01, 2007, Jesse Barnes wrote:
>>>>> I'm testing it now on my 965...
>>>> Bah... nevermind Robert, I see you're doing this already in
>>>> pci_mmcfg_reject_broken.  I'm about to reboot & test now.
>>> Ok, I've tested a bit on my 965 (after re-adding my old patch to
>>> support it) and the new checks are more complete, but my BIOS still
>>> appears to be buggy.
>>>
>>> The extended config space (as defined by the register) is at
>>> 0xf0000000 (full value is 0xf0000003 indicating 128M enabled).  The
>>> ACPI MCFG table has this space reserved according to Robert's new
>>> code, but the machine hangs due to the address space aliasing
>>> Olivier mentioned awhile back.  I don't have a PCIe card to test
>>> with (or any devices that require extended config space that I know
>>> of) so I can't really tell if Windows supports PCIe on this
>>> platform, but if it does I don't see how it would w/o having a full
>>> bridge driver and sophisticated address space allocation builtin.
>> Windows XP doesn't use MMCONFIG or any extended configuration space.
>> I believe Vista is supposed to, though. Not sure how they are
>> handling this issue.
> 
> Oh right... Vista will be the first to fully support PCIe & mcfg...
> 
>> Can you post what your board has for PNPACPI reserved resources (I
>> believe they're in /sys/devices/pnp0/*/resources IIRC, don't have a
>> Linux box handy right now). Full dmesg would also be useful, I think
>> it dumps out those reservations at boot nowadays..
> 
> BIOS update didn't help.  Here's the boot log and a dump of the pnp0 
> resources.

Curious.. It looks like the ACPI resources have the correct reservation 
for the MMCONFIG window according to what the register says the location 
should be. There's no other reservations that overlap with that range 
(f000000-f7ffffff), and according to the 965 datasheet there's nothing 
that's hard-coded to occupy that memory range. I can't really see what 
this range could be conflicting with.

What happens if you take out the chipset register detection, does the 
MCFG table give you the same result? Wonder if they're doing something 
funny with start/end bus values or something in their table. There's 
some code in my patch that prints out the important data from the MCFG 
table, can you tell me what that shows with the chipset detection taken out?

If that doesn't provide any useful information, I think we may need some 
assistance from Intel chipset/motherboard people to figure out what is 
going on here..

-- 
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@...pamshaw.ca
Home Page: http://www.roberthancock.com/
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