To start the X server on boot, use of a display manager such as lightdm seems to be the preferred method. However, if I start X by starting the lightdm service, I get a "No protocol specified" error. If I run the same command that lightdm calls according to
sudo /usr/lib/xorg/Xorg -core :0 :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
sudo as it doesn't start otherwise.) Everything appears to work.
A simple call to
sudo X :0
works as well.
This is on an Ubuntu 16.04 system and I am running everything remotely via SSH (No X11 Forwarding, xorg.conf is setup for virtual monitors, one for each GPU). When starting X manually, OpenGL acceleration and everything else works (tested via