Re: [chrony-users] Trouble with PPS

[Simon Haines <simon@xxxxxxxxxxxxxxxx>]

Also note that gpsd can sometimes erroneously create a second PPS source, thinking that the GPS device is connected with the serial line discipline exposing the PPS on a serial port pin. You can cross-check with ppstest, but your kernel debug seems to suggest that the source is indeed pps0.

Simon.

On Mon, Apr 16, 2018 at 5:23 PM Miroslav Lichvar <mlichvar@xxxxxxxxxx> wrote:

On Mon, Apr 16, 2018 at 09:01:11AM +0200, Alvaro Gamez wrote:
> I've tried your configuration (main difference was only the offset values).
> It sometimes seems to work, but not always.
>
> Here's a series of 'sources' requests output:
> #* GPS                           0   4    77    18    +90ms[ +306ms] +/-
> 6773us
> #? PPS                           0   4     6    39   -290ms[  -74ms] +/-
> 1622us

It seems the offset between the two refclocks is still too large to
allow a reliable lock of the PPS. Try increasing the offset of the SHM
refclock to 0.5.

--
Miroslav Lichvar

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