As part of the on-going saga to find out why my (by-now-not-so-brand-new) server was repeatedly rebooting, I wanted to keep the monitor from “going to sleep”/going into power saving mode.

As per anything Linux-related, there was a myriad of mixed advice from the Internet, with some relevant and others not so.

The Shortcut

The simplest working solution I could find (that worked for me) required two “separate” actions:

• The first instructions I came across worked:
  • navigate to System Settings > Brightness & Lock
    
  • set “Turn screen off when inactive for:” to Never
    

• But that only worked when logged in (i.e. the above setting was a per-user setting). The screen still blanked out when sitting on the log in page. Another search then led me to this solution… with but certain changes: as su (or using sudo):
  • in /etc/lightdm/lightdm.conf.d/ create a file 50-dpms.conf, containing:

[SeatDefaults]
display-setup-script=/usr/local/bin/dpms-stop

• • add root into the lightdm group*

usermod -a -G lightdm root

• • in /usr/local/bin/ create a file dpms-stop, containing:

#!/bin/sh
/usr/bin/xset -dpms

• • then make sure it is executable and owned by root:

chown root:root /usr/local/bin/dpms-stop
chmod u=rwx,go=rx /usr/local/bin/dpms-stop