Ubuntu – How to disable screen dimming after inactivity when this is already disabled at system settings

HOWTO: Disable screen saver while Flash is running

Run the following command in terminal:

mkdir -p ~/bin

Open gedit, or your preferred text editor and type this:

#!/bin/bash

# Cleanup any bad state we left behind if the user exited while flash was
# running
gconftool-2 -s /apps/gnome-screensaver/idle_activation_enabled --type bool true

we_turned_it_off=0

while true; do
    sleep 60
    flash_on=0

    for pid in `pgrep firefox` ; do
        if grep libflashplayer /proc/$pid/maps > /dev/null ; then
            flash_on=1
        fi

        ss_on=`gconftool-2 -g /apps/gnome-screensaver/idle_activation_enabled`

        if [ "$flash_on" = "1" ] && [ "$ss_on" = "true" ]; then
            gconftool-2 -s /apps/gnome-screensaver/idle_activation_enabled \
                --type bool false
            we_turned_it_off=1
        elif [ "$flash_on" = "0" ] && [ "$ss_on" = "false" ] \
                && [ "$we_turned_it_off" = "1" ]; then
            gconftool-2 -s /apps/gnome-screensaver/idle_activation_enabled \
                --type bool true
            we_turned_it_off=0
        fi

    done
done

Save this file as ~/bin/flash_saver.sh.

Go back into terminal and run:

chmod +x ~/bin/flash_saver.sh

To run this, go into terminal and type:

~/bin/flash_saver.sh

If you prefer, you can set this script to run at logon by doing the following:

1. Run the program "Startup Applications"
2. Click "Add"
3. Under name type "FlashMonitor" or something you will recognise
4. Under command type ~/bin/flash_saver.sh
5. Under comment (if you want) type a brief description. E.g. "Stops screen turning off when Flash is running"

Source: HOWTO: Disable screen saver while Flash is running - ubuntuforums

I seem to have found the cause of the problem, as well as the solution; apparently,there was some strange power management package installed.

I noticed a few weeks ago that the hard drive was powering down after three or four seconds (literally) of inactivity. So, after attempting to remedy the hard drive issue using the software from THIS page, I get a message telling me that tlp can't start because of a package called laptop-mode-tools, as well as a recommendation to remove it.

So, I powered up another Ubuntu laptop, which hasn't given me any real problems, and checked to see if it had that same package (using sudo apt-get purge laptop-mode-tools -s), and found that said package didn't exist, which made me assume it probably isn't particularly necessary. After removing both packages (that is, tlp and laptop-mode-tools), and rebooting the system, the both hard drive spin-down, and the dimming screen issues were solved.