On Fri, Jul 14, 2017 at 12:32:58AM +0200, Petr Kulhavy wrote: > I have two devices running linuxptp as slaves with the same configuration, > the only difference is that one uses SW timestamping and the other HW > timestamping. > Both report the same GM in `pmc GET TIME_STATUS_NP`, but they have a > different time, approximately the 36 seconds in difference. > > Generally I would expect both slaves to behave the same if they have the > same configuration and use the same GM. > What is wrong? What do I have to do in order to make them both have the same > time as the master?
As you observed, the difference is in the timestamping. With HW timestamping ptp4l keeps the PTP clock in TAI and it's up to phc2sys to convert it to UTC when it synchronizes the system clock. With SW timestamping ptp4l synchronizes the system clock, so it must convert it to UTC. I guess it would be possible to implement a mode where ptp4l keeps the PTP clock in UTC. I'm not sure how useful that would be. -- Miroslav Lichvar ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Linuxptp-users mailing list Linuxptp-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-users
