I’d like to close the laptop and use an external display with HDMI.
I choose the option “Switch off display” at “When laptop lid is closed” in the “Xfce Power Manager”.
The laptop is then in suspend/hibernate mode.
It’s not a hardware problem, because it works fine with KDE.
And changed ‘IgnoreLid’ from ‘false’ to ‘true’. After a restart: HDMI didn’t work at all!
I unchanged it then (made it ‘false’ again) but still: HDMI doesn’t work at all.
I also tested another HDMI cable.
I don’t know what happen.