| Re: [chrony-dev] PPS reference clock rejected because of high dispersion |
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On Tue, May 20, 2014 at 01:51:59PM +0200, Miroslav Lichvar wrote:
> On Tue, May 20, 2014 at 11:41:39AM +0200, Hattink, Tjalling [FINT] wrote:
> > When the offset between the PPS and SHM clocks is bigger than 0.5 / rate
> > the PPS samples are rejected. So if both refclocks disagree only the SHM
> > will actually publish samples. This shouldn't mark the SHM refclock as
> > falseticker right?
>
> Not sure where exactly is this coming from, but with your patch I'm
> seeing this:
>
> sources.c:711:(SRC_SelectSource)[20-10:58:03] Can't synchronise: no majority
> sources.c:913:(SRC_SelectSource)[20-10:58:35] Selected source PPS1
> sources.c:711:(SRC_SelectSource)[20-11:21:50] Can't synchronise: no majority
> sources.c:913:(SRC_SelectSource)[20-11:22:06] Selected source PPS1
> sources.c:711:(SRC_SelectSource)[20-11:39:12] Can't synchronise: no majority
> sources.c:913:(SRC_SelectSource)[20-11:39:44] Selected source PPS1
> sources.c:711:(SRC_SelectSource)[20-11:41:37] Can't synchronise: no majority
> sources.c:913:(SRC_SelectSource)[20-11:41:53] Selected source PPS1
It seems I didn't set the delay option correctly for this test and the
SHM source (NMEA from gpsd) didn't overlap with PPS occasionaly. So,
your patch will work if PPS samples are dropped until chronyd selects
SHM, but this is similar to not using the lock option except the PPS
samples are not accepted when SHM stops.
--
Miroslav Lichvar
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