12.04LTS & Gnome Classic-no effects, PC (not laptop)
I have tried a number of things to permanently stop the screen from going dark after 10 min of idle time. The screen comes alive with key or mouse movement. For a session, if I execute "xset s off" in a terminal, no more blanking takes place; the problem is it is not a permanent fix for the next boot.
What I tried after removing: xscreensaver and gnome-screensaver:
1)Sys Settings>Brightness & Lock set to "Never" turn screen off, Lock set to "Off"
2)Sys Settings>Power set suspend to "Don't Suspend"
3a) Made on the desktop a script file "kill_blanking.sh" which has only two lines: "xset -dpms" & "xset s off".
3b) Apps>Sys Tls>Prefs>Startup Apps: added kill_blanking.sh. Went to its install location "~./.config/autostart" and made the file there executable. The file is renamed to "kill_blanking.sh.desktop" and following is its contents:
4) Put "xset s off" in /etc/rc.local
5) Also played on the cmd line with "xset -dpms" and "xset s noblank" - interestingly the latter caused a gray screen vs going fully dark.
6a) Verified that "xdotool" was installed
6b) Similar to 3a) & 3b) above I made a script with the lines below and put them in the Startup Apps folder and made the resultant file executable:
while sleep 30 ; do xdotool keydown Shift_L keyup Shift_L ; done
7) It was mentioned that updates(Update Manager) may correct problem, I have declined to use updates. If there is a specific update that does the trick, then my all means please post.
I would prefer a method to just make a few manual entries to permanently stop the screen from going dark after 10 minutes of idle time.