I have been stumped by a problem with Devuan 1-beta running on 6th
generation Intel processors [i5-6200u, celeron n3050]. I am using openbox
as a window manager/desktop [but same happens with XFCE4], starting from a
tty with:

startx

which brings up openbox and an lxterminal. All is fine until I attempt to
exit xorg and return to the tty: the following errors are issued and the
screen freezes, unresponsive to anything other than a power cycle:

  xinit: connection to X server lost
  waiting for X server to shut down XIO: fatal error 4
    (Interrupted system call) on X server ":0"
  after 614 requests (614 known processed) with 0 events
    remaining
  .error setting MTRR (base = 0x..., size=0x..., type=1)
    invalid argument (22)
  (EE) server terminated succesfully (0).  Closing log file.

The /var/log/Xorg.0.log file is corrupted.

my .xinitrc is a simple

lxterminal&
exec openbox

>From the error messages, you would think think xorg completed fine, but I
put "echo" messages in "startx" before and after the "xinit" command, and
the second does not appear.

I am using Void Linux [4.5.2 kernel] on the 6200u laptop without problems,
but I also installed Slitaz Linux, which has a 3-series kernel.

I would appreciate any help that others here can give.

Jack