I have my computer set to turn the screen off after a period of inactivity. If I move my mouse slightly the monitor will indicate that it is receiving a signal and the backlighting will come on, but the screen is still black. When left like this for around five seconds, the monitor will indicate that it is no longer receiving a signal. Moving the mouse again at the black screen instead of waiting causes the screen to come on fully.
Pressing a key when the screen is "asleep" (e.g. the screen is off) will cause the screen to come on fully, but it does briefly show a black screen after receiving a signal. This seems to indicate that there are two separate actions which happen to "wake" the screen. If so, what are they, and why does it work like this?
I have observed this to occur on several different computers with Ubuntu 13.04 and 13.10 using unity. My main computer has a GTX 660 Ti with nvidia-319-updates installed and is hooked up to a lcd monitor and a lcd HDTV via DVI and HDMI respectively .