[ntp:questions] Ignore one server except in extreme conditions?

A C agcarver+ntp at acarver.net
Thu Nov 17 06:51:37 UTC 2011

On 11/16/2011 22:43, Dave Hart wrote:
> On Thu, Nov 17, 2011 at 06:35, A C<agcarver+ntp at acarver.net>  wrote:
>> On 11/16/2011 16:09, Dave Hart wrote:
>>> You don't have to use two separate drivers for NMEA and PPS, even with
>>> the signals coming in on different serial ports.  At least in 4.2.7,
>>> the NMEA driver tries /dev/gpsppsX for PPSAPI before falling back to
>>> using the same port as for NMEA, /dev/gpsX.  In this configuration,
>>> you don't need to mark any peers as prefer, which I much prefer
>>> compared to using ATOM and marking all your network peers and NMEA
>>> prefer, because prefer has profound effects on mitigation which are
>>> tricky to wrap your head around.
>>> I encourage you to try a recent 4.2.7 ntpd with only the NMEA driver
>>> with its PPS handling enabled
>> I compiled the latest development version 4.2.7p234.  The NMEA driver does
>> not pick up /dev/gpspps for whatever reason even if I have the symlink
>> defined.
> Did you try /dev/gpspps0, assuming server  Did you
> "fudge flag1 1" to enable NMEA's PPSAPI support?
> Cheers,
> Dave Hart

Yeah, I did all that and it never worked.  It would not find and use the 
PPS signal.  But as soon as I split it to its own driver (and got the 
flags right on the PPS driver) it worked fine.

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