GL screen hacks corrupting display

[Rob VanFleet <rvf@linux-cs.tccw.wku.edu>]

I'm using potato with the /dev/3dfx - Mesa combo for 3D.  When I run a GL
screen hack like gears or morph3d, it runs accelerated and looks nice.  The
problem is that when I exit them, the display in X is completely whacked; I
can't do anything.  So far, I've just been Alt-F1'ing back to a console and
hitting Ctrl-C to kill the X server.  This activity is confined to xscreensaver
running them.  When I run them from the command line with no options, I don't
get the corrupted display, only when I run them with '- root', as xscreensaver
does.

Does anyone know why this happens, how to prevent it, or at least if there is a
way to reset the X display without restarting the server?

-Rob