SMP system not running SMP

[Peter Seebach]

One useful data point:  When the system fails, a verbose boot gives
additional information:

	(probe0:sbp0:0:0:0:0): error 22
	(probe0:sbp0:0:0:0:0): Unretryable error

This repeats up through 0:0:6:0.  Then the system stays hung.

I haven't got an easy way to hook up a serial console, and for no obvious
reason, my IDE drive with no ahd controller in the kernel isn't booting
today either.

I don't know how to perform a verbose boot with ACPI disabled.  "set
hw.acpi.debug.disable=all" does not disable ACPI enough to prevent this hang.

-s