Re: [gpsd-users] Disable or restart PPS in gpsd?

[Gary E. Miller]

Yo Alexander!

On Wed, 03 Sep 2014 00:18:40 -0700
Alexander Carver <address@hidden> wrote:

> On 2014-09-03 00:13, Gary E. Miller wrote:
> > Yo Alexander!
> > 
> > On Wed, 03 Sep 2014 00:06:09 -0700
> > Alexander Carver <address@hidden> wrote:
> > 
> >> I'm having some trouble with PPS on version 3.6 in kernel 3.2
> > 
> > Both those are petty old, you'll need to upgrade.
> 
> The kernel is the latest image in Debian's stable branch.  There isn't
> one available up from that.  I can replace gpsd with a tarball instead
> of a package, not sure it will help in this case, though.

Just do not expect any patches on such an old gpsd.

> >> I get this once per second, as you can see, until I restart gpsd.
> >> The problem is that gpsd is also creating the pps0 device which
> >> ntpd is attempting to use as well.  Restarting gpsd alone without
> >> restarting ntpd does not remove pps0 and instead recreates it as
> >> pps1.  I have to restart both services to fix gpsd and restore
> >> pps0.
> > 
> > If gpsd is using the PPS then no need for ntpd to use PPS as well.  
> > Avoid the confusion and just let gps handle the PPS fpr ntpd.
> 
> It's not working properly which is why I'm resorting to ntpd's PPS
> driver.  If there's even the slightest hiccup in the SHM(0) stream,
> ntpd boots both SHM's and I'm left with nothing.  The SHM(1) stream
> is also unstable (jitter) compared to the actual PPS signal.  Using
> the PPS driver, the jitter is much better.  Also with the PPS driver,
> the system will fall back to another source if gpsd fails to deliver
> a timestamp properly and the PPS will continue ticking using the next
> available source for numbering the seconds.  The problem then is my
> logs fill up with once-per-second messages about the KPPS error until
> I restart gpsd.

Sounds like you just want KPPS off in gpsd.  So just compile it without
pps support.

What sort of jitter difference are you seeing?

RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97701
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