alpm0: Could not allocate Bus space

[Peter Jeremy]

I'm trying to resurrect an Asus P5A-B system and the power management
is failing.  The relevant parts of the dmesg are:

FreeBSD 5.3-RELEASE-p5 #2: Sat Mar  5 21:54:19 EST 2005
...
bios32: Found BIOS32 Service Directory header at 0xc00f9b80
bios32: Entry = 0xf0530 (c00f0530)  Rev = 0  Len = 1
pcibios: PCI BIOS entry at 0xf0000+0x560
pnpbios: Found PnP BIOS data at 0xc00fcfb0
pnpbios: Entry = f0000:cfe0  Rev = 1.0
pnpbios: OEM ID cd041
acpi0: <ASUS P5A-B> on motherboard
acpi0: [MPSAFE]
...
found->  vendor=0x10b9, dev=0x7101, revid=0x00
bus=0, slot=3, func=0
class=06-80-00, hdrtype=0x00, mfdev=0
cmdreg=0x0001, statreg=0x0280, cachelnsz=0 (dwords)
lattimer=0x00 (0 ns), mingnt=0x00 (0 ns), maxlat=0x00 (0 ns)
...
alpm0: <AcerLabs M15x3 Power Management Unit> at device 3.0 on pci0
alpm0: host/noslave 74K
alpm0: 0x20 bytes of rid 0x14 res 4 failed.
alpm0: Could not allocate Bus space
device_attach: alpm0 attach returned 6

I've had a look through the archives but not been able to find this problem.
Has anyone else seen it and how would I go about fixing it?

-- 
Peter Jeremy