I messed up something in nvidia-settings, not sure what and after reboot, echo $DISPLAY gives nothing.
I tried to export it manually
After reboot, display is still empty, i tried
echo DISPLAY is $DISPLAY, still nothing.
Then i deleted nvidia and installed nouveau, gives me same black screen or computer manufacturer logo.
section "screen" Identifier "Screen0" Device "Device0" Option "UseDisplayDevice""none"