>It shouldn't be hard at all; just add a `control channel' pointer to
>the MI driver's per-channel state.  Set up the control-channel pointer
>to match the control wiring: cross-pointers iff cross-wired.

Whoa, my idea exactly :-)

>BTW, the Alpha and pmax use slightly different versions of the
>4.4bsd/pmax scc driver; I'm still(!) trying to finish merging those
>back; I've got the differences down to, surprise, console-driver
>initialisation.  I don't think there's never been a good reason for
>the Alpha and pmax ports having separate versions of this driver.  I
>hope the pmax and alpha can share an `zs at ioasic' driver from day
>one.

Well ... would you like my current zs driver so you can make sure it's
pmax-friendly?  If you're willing to help out with the keyboard and mouse
channel drivers, that would be even better.  I don't have serial console
support in it (yet).

If we could make a /sys/dev/tc/zs.c, that would be really great.

--Ken