> >>> Why do you need the SHM 0? You can use SHM 1 or SOCK.Some cookbooks (e.g.,
> https://support.ntp.org/bin/view/Support/ConfiguringSHMRefclocks ) use both SHM 0 and SHM 1
That might had been necessary with very old versions of gpsd (IIRC it
originally required something to bring the system clock close to the
PPS before it locked), but with more recent gpsd versions the
configuration should be one of the following:
chronyd/ntpd can take PPS&NMEA directly & determine the name of the second,
or gpsd can intervene and do some of the work. The options are confusing and poorly documented.
gpsd altered the picture without warning; fortunately the number of affected users seems to be small .
I did a git bisect last year: the problem appeared between release-3.21-26 and release-3.21-30..
Since the gpsd team doesn't see an issue I stopped looking. If the results might be useful I could dig deeper (e.g., turn off GPGSV or other sentences.).
Steve