I have a Thinkpad carbon X3 2015 model, which I am pretty happy with.

As of several days ago, it no longer sleeps when I close the lid with Gnome. The trigger was moving to Brisbane, in Melbourne it was fine. Hasn't come good since moving back to Melbourne however.

If I manually type in "sudo systemctl start systemd-suspend" then it goes to sleep fine. So I suspect this isn't the typical issue of suspend not working, it is more like suspend isn't even getting triggered.

Looking at /var/log/auth.log I see events being generated by systemd-login for "Lid closed" and "Lid opened" - how do I debug why these aren't getting turned into sleep events?

It is possible this problem come about as a result of upgrading from a 4.0 kernel to a 4.1 kernel, however I couldn't get get reproducible results under 4.0. As in if I make a random change to the system, it can start working and after a reboot it stops working.

Thanks