Re: [chrony-users] using chronyd with gpsd, without PPS support

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On Sun, Jan 16, 2011 at 11:58:23AM +1100, Michael Ashley wrote:
> Hi folks,
> Sorry if I'm missing something obvious, but is it possible for chronyd
> to synchronize with gpsd without LinuxPPS support?

Yes, it should work.

> My kernel (Debian squeeze 2.6.32-5-686) doesn't appear to have
> PPS. I'm using a version of gpsd pulled with git just now, and gpsd
> 2.95.
> I naively tried adding
>   refclock SHM 1 poll 3 refid GPS1
> to my /etc/chrony.conf file, but it doesn't pick up anything from
> the GPS (which is working, confirmed by listening in to the gpsd
> socket).
> GPS1 appears in "sources" as:
> MS Name/IP address           Stratum Poll LastRx Last sample
> ============================================================================
> #+ GPS1                          0    3    10y     +0ns[   +0ns] +/-    0ns

Do you get anything when the segment 0 (message decoded
timestamps) is used instead?

That would mean the communication between gpsd and chrony is working,
but gpsd doesn't provide the PPS timestamps.

What is the output from gpsd -n -N -D 6 /dev/ttyS0 | grep -i 'pps\|ntp' ?

Miroslav Lichvar

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