In System Settings / Power Management / Energy Saving there’s “Button events handling” option.
When I select this:
When laptop lid closed -> Suspend
Even when external monitor is connected -> unchecked
then connect external monitor through D-Sub and close the lid the system goes to sleep.
I tried to check and uncheck the second option but the problem still persist. In Kubuntu, Ubuntu and Debian with Gnome3 I didn’t have this issue.
How could I workaround this?
This could either be a GPU driver or a TLP settings issue, I’d bet on the former.
Rolling is based on Manjaro and thus uses different, often times newer, kernels, drivers, xorg, etc. than Ubuntu and it’s derivatives.