ubuntu eco mode
When I lock the screen, the display goes back to the log in window. Then, if I don't touch the mouse nor the keyboard, after some time (minutes) the screen goes black (I guess this is call saving mode, or eco mode, or something similar).
BUT after a few seconds, the screen goes back to the log in screen, as though the mouse or the keyboard was touched, which is not the case.
How to correct this unwanted behaviour ?