I have this weird bug, I lived with it for long, I got enough and want to solve it with your help.
my laptop Lenovo legion y530 came with Nvidia

I followed the wiki page to use bumblebee, I used it before with other laptops.
The issue is I use intel-virtual-output to use an external monitor with nvidia GPU. after 20 min or less the external monitor goes black if there is not activity.
when I watch a movie for example or doing a presentation, it goes black and I have to move the mouse to wake it up again (annoying).
I disabled Blank screen (set it to Never) in settings and disabled Dim screen when inactive.
the built screen does not become black. but the external one does every 20min or around it.
What should I do to disable this for the external screen too ?
Thanks