I'm using NetBSD/i386-current on my workstation, and the kernel
messages at boot-time related to its use as a graphics console look
like this:

   vga0 at pci0 dev 11 function 0: Matrox MGA Mystique 1064SG (rev. 0x03)
   wsdisplay0 at vga0 kbdmux -1: console (80x25, vt100 emulation)
   wskbd0 at pckbd0: console keyboard, using wsdisplay0
   wsmouse0 at ums0 mux 0
   wsdisplay0: screen 1 added (80x25, vt100 emulation)
   wsdisplay0: screen 2 added (80x25, vt100 emulation)
   wsdisplay0: screen 3 added (80x25, vt100 emulation)
   wsdisplay0: screen 4 added (80x25, vt100 emulation)
   wsmux1: connecting to wsdisplay0

I run the default (current) XFree86 on it, using XF86_SVGA run from
xdm.  To access the graphics device, it uses the aperture driver:

   crw-r--r--  1 root  wheel  29, 0 Nov  7 09:47 /dev/xf86

   aperture-2.0nb1     XFree86 Framebuffer "aperture" driver for NetBSD/i386

Updating to -current as of 2001-11-06, my system consistently crashes
the second time the graphical use of the console is initialized.  That
is, it boots up nicely, and I can log in under X, which works as it
should.  However, if I log out, so that xdm restarts X, or if I switch
to a non-graphical console (which works fine), and then back to the
screen with X on it, the system hangs for a while (20 seconds, maybe),
and then reboots.  No crash dump, no error messages.  Everything
freezes solid for a little while, and then the screen clears, and the
BIOS reboots the machine.

The last time I updated to a fresh -current was 2001-09-27.  I have
run many different incarnations of -current on the machine, and have
never seen this problem before.

Any ideas?

-tih
-- 
Puritanism -- the haunting fear that someone, somewhere, may be happy.