[Linuxptp-users] phc2sys/tmemaster and NTPSHM

[Lynch, M. <mik...@hb...>]

I am writing to, hopefully, get some clarification on use of timemaster, phc2sys, and ntpshm.  There is a thread in the archives (2014 IIRC) that looked like it was referring to an early version of 'timemaster' and it mentioned configuration options for GPS devices.  None of those are mentioned in the documentation for timemaster and I was wondering if GPS device configuration was never added and/or will be added in the future?  Also, I see that phc2sys supports an NTPSHM servo.  Does that mean it's possible to use gpsd directly with phc2sys and have it synchronize the system clock and, if my PTP hardware clocks are masters, the PTP clocks as well?  Basically what I want to do is to configure ptp4l as boundary clock and synchronize the PTP clocks and system clock to a GPS device.  The whole thing should failover to PTP synchronization if the GPS device fails or is not available.  I know how to do almost all of this but I'm a bit unclear on whether or not chronyd is actually needed in the mix and/or what role it would play?  E.G.  If phc2sys is provided GPS time via NTPSHM will it synchronize other clocks (PTP/system) to GPS time or must the system clock be synchronized via chronyd and the PTP clocks then be synchronized to the system clock?  Thanks for any guidance anyone can provide.

Mike