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.

apt-cache showpkg says:

xorg 1:7.7+7
xinit 1.3.4-1

I would appreciate any help you can provide with this bug.

addendum: I have been using xorg and openbox in this way on older processors such as intel i3-2330M and i3-3217U without problems since the first Devuan releases.

addendum2: I installed refracta8 to the i5-6200u machine, and it froze with a blank screen when logout/reboot. The CD version of refracta has no such problems [it can reboot the CD from xfce]. The installed xorg is just copied verbatim from the CD, so it must be the same.