acpi causes missing serial port on HP BL10e

[Kris Kennaway]

If I build a kernel with acpi on this HP proliant BL10e blade system, it 
doesn't probe sio0:

without acpi:

sio0 at port 0x3f8-0x3ff irq 4 flags 0x10 on isa0
sio0: type 16550A, console
sio0: [FILTER]
sio1 at port 0x2f8-0x2ff irq 3 on isa0
sio1: type 16550A
sio1: [FILTER]

with acpi:

sio0: <Standard PC COM port> port 0x2f8-0x2ff irq 3 flags 0x10 on acpi0
sio0: type 16550A, console
sio0: [FILTER]

note: the port at 0x3f8 didn't probe.

If someone is interested I can provide the acpidump.

Kris