Hi,

On an HP Omnibook 6000 (i386), I added the following options to my config file 
(source is current from 10 Jan.):

ioapic* at mainbus?

acpi0           at mainbus0
options         ACPI_PCI_FIXUP=1        # PCI interrupt routing via ACPI
options         ACPI_ACTIVATE_DEV=0     # If set, activate inactive devices

# ACPI devices
acpiacad*       at acpi?                # ACPI AC Adapter
acpibat*        at acpi?                # ACPI Battery
acpibut*        at acpi?                # ACPI Button
acpiec*         at acpi?                # ACPI Embedded Controller
acpilid*        at acpi?                # ACPI Lid Switch
acpitz*         at acpi?                # ACPI Thermal Zone

# Mainboard devices
com*            at acpi?                # Serial communications interface
fdc*            at acpi?                # Floppy disk controller
lpt*            at acpi?                # Parallel port
npx*            at acpi?                # Math coprocessor
pckbc*          at acpi?                # PC keyboard controller
wss*            at acpi?                # NeoMagic 256AV in wss mode

The resulting kernel makes the computer reboot during what appears to be the 
acpi section.

Here are three examples of (garbled) dmesg output:

(Node 0xc0922320), AE_NOT_EXISod execution failed [\_SB_.PCI0.

acpi0 at mainbus0
acpi0: X/RSDT: Oe

 mainbus0
acpi0: X/RSDT: OemId <HP-MCD,EA RSDT ,01820000>, AslId < LTP,00000000>

Sverre