x86_64 (EM64T Core2 Duo, DG965RY) PCI mmconfig regression - complete hangs on boot - ACPI interaction?

["Robin H. Johnson" <robbat2@gentoo.org>]

[Please CC me, I'm not subscribed to LKML.]

I recently picked up a new server of really new hardware, and I've run
into a number of issues with the latest git HEAD kernels. I'll make
separate posts for each of the issues.

CPU: Intel Core 2 Duo E6400
Motherboard: Intel DG965RY
BIOS revisions: July/07/2006 AND September/06/2006 (tried both)

The most significant of them - is that somewhere between 2.6.17.11 and
2.6.18-rc6-git4, MMCONFIG is now being used, but leads to a complete
hardware hang (SYSRQ does not respond).

As of the current HEAD, I need to boot with pci=nommconf OR acpi=off,
otherwise the machine completely freezes a short while into the PCI
detection routine. Using acpi=off disables SMP, which is not desirable
on this box, but otherwise does work.

All of the following boot params lead to a failure:
pci=assign-busses
acpi=strict
pci=noacpi
acpi=ht
pci=nomsi

At the following URL, I have photos and transcriptions of the kernel
boots, as well as dmesg output from working 2.6.17.11 and .18-rc7-git1
with pci=nommconf.
http://www.orbis-terrarum.net/~robbat2/x86_64-mmconfig-failure/

-- 
Robin Hugh Johnson
E-Mail     : robbat2@gentoo.org
GnuPG FP   : 11AC BA4F 4778 E3F6 E4ED  F38E B27B 944E 3488 4E85

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