riz@boogers.sf.ca.us said:
> when booting with serial console, ttyE0 does not get configured.  (I
> can't start a getty on it from /etc/ttys) ttyE1 *does* get configured
> with the default wscons setup

Have a look at /etc/wscons.conf. ttyE0 is commented out because
people got nervous about the warnings which got issued if it was
already set up as console. Removing the comment should do it.

> ttyE1
> *does* get configured with the default wscons setup, and I can start
> a getty on it just fine, but I don't know the magic incantation
> to get X to use it.

A "vtNN" argument to the X server should do it - my
/usr/X11R6/lib/X11/xdm/Xservers contains eg
:0 local /usr/X11R6/bin/X vt05
which makes it use ttyE4.
(Note that X starts counting at 1. Probably written in FORTRAN.)

best regards
Matthias