ACPI vs. Tyan Tiger K8W(S) -- recent CURRENT dies during boot

[Ed Hall]

I have a Tyan Tiger K8W(S) (BIOS v1.02) with an Opteron 244 and 1GB.
It's worked just fine with CURRENT until I cvsup'd and rebuilt yesterday.
Now it panics early in boot with:

---------------------------------------------------------------------------
ACPI PCI link initial configuration:
pci2: <ACPI PCI Bus> on pcib1
pci2: physical bus=2
        map[10]: type 3, range 32, base d0000000, size 28, enabled
pcib1: device (null) requested decoded memory range 0xd0000000-0xdfffffff
        map[14]: type 4, range 32, base 0000a800, size 8, enabled
pcib1: device (null) requested decoded I/O range 0xa800-0xa8ff
        map[18]: type 1, range 32, base ff5f0000, size 16, enabled
pcib1: device (null) requested decoded memory range 0xff5f0000-0xff5fffff


Fatal trap 12: page fault while in kernel mode
cpuid = 0; apicid = 00
fault virtual address   = 0x2
fault code              = supervisor read, page not present
instruction pointer     = 0x8:0xffffffff80179580
stack pointer           = 0x10:0xffffffff8078f4f0
frame pointer           = 0x10:0xffffffff8078f500
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 0 (swapper)
[thread 0]
Stopped at     AcpiNsMapHandleToNode+0x20:    cmpb     $0xf,0(%edi)
db>
--------------------------------------------------------------------------

(Please forgive any errors in transcription.)

It's been a couple of months since I updated this system before, so I'm not
sure at what point things went off the rails.  But it's been quite stable
up until now.

It boots up with ACPI disabled, but neither sound or X11 will work (not
surprisingly).

Any ideas how to proceed from here?

		-Ed