On Wed, May 27, 2015 at 07:37:39PM +0200, Richard Cochran wrote: > 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.
Is that always preferred over slew? > > Would happen anything bad if the servo set the frequency to a non-zero > > value? > > This would cause a growing phase offset. Ok, but adjusting frequency to correct a phase offset is still fine, right? > > 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. Hm, so the offset normally stays at zero or is it stepping on each update? If there is no noise in the measurements, then one step on start and no more clock updates would make sense. If there is some noise I think it would be still useful to let the servos adjust the frequency similarly to a case with a stabilized clock (e.g. OCXO), which has a fixed but non-zero frequency offset. In seems odd to me to call the servo function and then ignore its result. In general this breaks the internal state of the servo since the assumption is that it is always controlling the clock. -- Miroslav Lichvar ------------------------------------------------------------------------------ _______________________________________________ Linuxptp-devel mailing list Linuxptp-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-devel
