ahc/ahd locking

[Matthew Dillon]

:I took the changes out, and I'm running a stock kernel, and it seems to
:be ok.  So it's gotta be something going on.  Maybe i should just use
:lockmgr locks, and forget the intr/serializer stuff?
:
:--Peter

    It's up to you.  lockmgr will work.  The advantage of using the
    serializer is that the interrupt subsystem can determine whether the
    interlock will block *before* trying to call the interrupt procedure,
    which can be beneficial when multiple devices share the same irq.

    I'd say... get it working and stable first, then worry about making
    it efficient.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>