[LinuxPPS] Stick to PPS, even if the prefer server fails

[Thorsten Mühlfelder]

Hi
My setup is as follows:

Server A <--- GPS 
  |
  |
Server B <--- HP cesium frequency normal


Server A gets it's timestamps from GPS.
Server B gets it's timestamps from Server A and PPS from the HP cesium. Server A is marked as prefer because otherwise PPS won't work.

My problem is:
If Server A loses the GPS signal, it falls back to LOCAL and begins to drift away. In the beginning Server B doesn't care about that and stays to the PPS. But later it disconnects PPS and runs on Server A again. So both servers drift away. In my opinion Server B should stay to the PPS signal. Is there anything I can do about that?