Comment 16 for bug 958279

Referring to my post above...
I confused one for another , I actually had to enter a TIMED shutdown command to reboot my system while testing the display switch-on/off because the system was running but not responding my inputs at all after my screen was going off.

I also have tested some of the solutions I've read above and found some odd things.

-- So , after installing fglrx-updates I had no xorg.conf file by default (which is ok..) ;

-- I generated one with sudo amdconfig --initial and set DPMS to false , then rebooted ... this workaround actually "worked" for me in the sense that it basically prevented the system to send a standby/switch-off signal to the monitor ... instead, it was just blanking and keeping it powered on. (so far so good)

-- Then out of curiousity I tried setting the DPMS back to true, after rebooting the system I noticed it was working,
the display was correctly entering and exiting the standby mode. Thus, my problem was that I had no xorg.conf file by default.
So yay, everything worked fine ... no, not everything actually.

-- I don't know why but having an xorg.conf file somehow affects my graphic effects , for example when I'm in the KDE system-settings panel there's a fade-out effect when moving the mouse-pointer from one icon to another ... well that one graphic effect is now broken, the fading effect is glitchy and makes some artifacts when fading ... this does not happen when I have no xorg.conf file.

Both ways I have something malfunctioning ... either graphics-ok + screen standby not working or the other way around.
I guess I'll be keeping my /etc/X11 without an xorg.conf file and just disable the powermanagement option for display standby