I updated my system last Monday, and also implemented migrated to systemd more than I had.
Since then Myth tv doesn't record. When I looked at it, I can watch TV if either the computer has been restarted or I restart mythtvbackend. This happens now with both the old initscripts rc.d script and the systemctl start mythbackend.service. However if the screen saver has kicked in it seems there is no signal or signal lock.
Has anyone else seen this sort of behaviour?