On Wed, May 27, 2015 at 03:05:14PM +0200, Miroslav Lichvar wrote: > Is it not possible that the offset will change when there is some > restart or reconfiguration in the PTP network?
Yes, but any phase offset that suddenly appears is fixed by a jump. Using SyncE only makes sense when you have a chain (or tree) of devices. The "first" device (at the start of the chain) will adjust its frequency normally to match the GM. All of the other devices in the chain never adjust their frequencies, because this happens in hardware automatically. Of course, it is important for a SyncE device to know whether the "previous" peer in the chain is SyncE capable or not, but PTP does not tell you this. There is an ITU standard that covers simple SyncE notifications, and you need some kind of SyncE management program to restart ptp4l when the status changes. > Would happen anything bad if the servo set the frequency to a non-zero > value? This would cause a growing phase offset. > The servos need to be able to adjust the frequency to correct offsets > smaller than the step threshold. If adjusting frequency is not > allowed, the only option would be to always step. Yes. I have 'freq_noadj 1' together with 'step_threshold 0.000000001' in the configuration. Thanks, Richard ------------------------------------------------------------------------------ _______________________________________________ Linuxptp-devel mailing list Linuxptp-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-devel
