> No, the puc0 is a multifunction device that has ns16550 controllers
> embedded in it.  The problem is when you have different types of serial
> controllers.  For example:
>
> com0	at pci dev ? function ?
> sab0	at pci dev ? function ?
> zs0	at sbus slot ?
>
> Where both of those are mutually exclusive and have the same physical
> location in the machine.  Since they have different major numbers you

can you explain this?
two drivers for SAME port?!?!?!?!