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

[Alexander Carver]

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.

> 
>> 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.