It seems like systemd is loading bluetooth.service but it’s not picking up the pairings of keyboard and mouse until after a user has logged (lightdm) in. Thus one can’t log in without attaching a usb keyboard.
Do I need a custom systemd service to make this happen or just edit the bluetooth one? . Many times in systemd one just needs a dependency. In other words bluetooth service may be getting loaded too late or early.
Has someone already faced and solved this issue for mate 17.04 on an amd64 box?