It would be a control message to the appropriate device that in turn
calls the devtab[whatever]->config routine.  The first argument is
0 or 1, meaning unconfigure or configure.  Look at etherconfig in
bitsy/devether.c.  Its already in devtab, but noone uses it except
bitsy/devpcmcia.c.  I was going to make it a bit more universal but
it was just at the time pb was doing the pccard interface for the
pc and I got deflected.  I'ld like the pcmcia/pccard interface on the
pc's to work the same way as the one in the bitsy.  Maybe in my next
lifetime or maybe someone out there will decide its a good idea and
find the time.