> 21.07.2022 10:20 Miroslav Lichvar <mlich...@redhat.com> wrote: > > > On Wed, Jul 20, 2022 at 05:57:57PM +0200, Jakub Raczyński wrote: > > So this setup seems to be correct and from the phc2sys log I sent > > previously it seems to be. So it seems that phc2sys is correctly writing > > timestamps to ntpshm only when it is Slave. > > No, that's not correct. Try running the ntpshmmon tool from gpsd to > see that phc2sys is writing new samples in both directions.
You are mistaken, I did try ntpshmmon and it does write to ntpshm only in one direction as Slave. When device switches to Master it stops writing to ntpshm. But from your reaction I assume this is unintended? Because it would work perfectly if not for the ntpd reset bug. > > > The only problem is caused by ntpd reset - it starts synchronizing to PTP > > (ntpshm) even if it shouldn't as is it Master. > > If you have multiple sources configured for ntpd, it could be > rejecting the SHM as a falseticker when the TAI-UTC correction in > phc2sys flips. On a restart/reset and depending on the polling > intervals, it could temporarily select the SHM source for > synchronization and later reject it again. > > Try it with SHM as the only source. That should make it obvious > that this cannot work. I did and yet again it works and switches direction of synchronization perfectly. Yet again, goal is to achieve ntpshm as clock source in Slave state and CLOCK_REALTIME as Master clock for the network. I do not expect ntpshm to be two-way synchronization clock. As such, since data is not written to ntpshm, I assume that phc2sys does select direction incorrectly after ntpd reset when significant offset was present. Seems like servo reset issue that does not update direction or sets it incorrectly. I will probably debug it in following days but I had hoped you could be of assistance. Best regards Jakub Raczynski _______________________________________________ Linuxptp-users mailing list Linuxptp-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-users
