> (What about PCI-ISA busses in non-i386 machines, then? Do we treat
> them the same way? I'm pretty sure such things do exist...)

They definitely do.  For example, my MBX821 PowerPC board has:

       Host bus            PCI bus           ISA bus
  CPU <--------> Host-PCI <-------> PCI-ISA <-------> ISA
                  bridge            bridge            devices
>
> > (I'm in favor of ripping out "isa* at pcib?" and "isa* at pceb?" and
> > just leaving "isa0 at mainbus0", since the former two give the
> > not-very-useful impression that the entire ISA bus is behind them.)

Only in i386, I presume?  In my case, the ISA bus _is_ behind pcib.

Regards,

David Querbach
Real-Time Systems Inc.