Got rid of commandkey. I had planned to do that for a while but hadn't
because it didn't seem to be causing any serious problem.
That was precisely it. /dev/pps0 wasn't getting created by the kernel until
later in the bootup process. I had to make some changes to chronyd.service
and gpsd.service to ensure that both come up properly on boot. Main thing
was to delay chronyd startup.
I had to make a change to the chrony.conf to add makestep. For reasons I'm
not yet sure of, the system clock on this BeagleBone always comes up
waaaaaay off (like 26 days) at boot time. It would take an eternity for
chronyd to get in sync with that big of a delta. The only purpose in life
for this little server is to provide NTP so I'm not worried about any other
applications being sensitive to the clock step. Just seems like the kernel
would persist the system clock periodically so that when it boots up it's
at least in the ballpark. I thought I read that it does that somewhere but
can't remember where. I'll need to go back and research that. I may end up
having to add some sort of battery backed RTC to this design to address it.
On Wed, Nov 29, 2017 at 10:19 PM, Bill Unruh <un...@physics.ubc.ca> wrote:
>
> GEt rid of the commandkey line in chrony.conf
>
> Nov 03 17:16:53 beaglebone chronyd[590]: commandkey directive is no longer
>> supported
>> Nov 03 17:16:53 beaglebone chronyd[572]: open() failed on /dev/pps0
>>
>
> Does /dev/pps0 exist when chrony starts? Chrony will not load the pps-ldisc
> module itself. You have to make sure it is loaded before chrony starts
>
> I do it by putting a script into /etc/init.d with the appropriate pointer
> in
> the /etc/rc.d/rc?.d directories. (NOt sure what the Debian numbering is of
> the rc?.d )
>
> --------------------------
> #! /bin/sh
> #
> # gps Support for NTP i gps clock. #
> # chkconfig: 345 70 15
> # description: gps is a module to read the PPS
> # Get config.
> . /etc/sysconfig/network
>
> # Get functions
> . /etc/rc.d/init.d/functions
>
> module="gps"
> device="gps"
> mode="664"
> group=wheel
>
> case "$1" in
> start)
> gprintf "Starting gps pps service"
> modprobe pps-ldisc
> ldattach 18 /dev/ttyS0
> ;;
>
> stop)
> killall ldattach
>
> echo
> ;;
> status)
> status ldattach
> ;;
> restart)
> $0 stop
> $0 start
> ;;
> *)
> gprintf "Usage: gps {start|stop|status|restart}\n "
> exit 1
> esac
>
> --------------------------------------------
>
>
> Nov 03 17:16:53 beaglebone systemd[1]: chrony.service: Control process
>> exited,
>> code=exited status=1
>> Nov 03 17:16:53 beaglebone systemd[1]: Failed to start chrony, an NTP
>> client/server.
>> Nov 03 17:16:53 beaglebone systemd[1]: chrony.service: Unit entered
>> failed state.
>> Nov 03 17:16:53 beaglebone systemd[1]: chrony.service: Failed with result
>> 'exit-code'.
>>
>> I verified PPS with ppstest
>>
>> debian@beaglebone:~$ sudo ppstest /dev/pps0
>>
>
> So it looks like /dev/pps0 was eventually started. It is a timing problem
> --
> pps0 needs to be created before chrony starts
>
>
> trying PPS source "/dev/pps0"
>> found PPS source "/dev/pps0"
>> ok, found 1 source(s), now start fetching data...
>> source 0 - assert 1478194022.222516784, sequence: 573 - clear
>> 0.000000000,
>> sequence: 0
>> source 0 - assert 1478194023.305849881, sequence: 574 - clear
>> 0.000000000,
>> sequence: 0
>> source 0 - assert 1478194024.389182301, sequence: 575 - clear
>> 0.000000000,
>> sequence: 0
>>
>> If I then start chronyd manually using "sudo systemctl start chrony" it
>> starts
>> successfully and I can see both sources
>>
>> debian@beaglebone:~$ chronyc sources
>> 210 Number of sources = 2
>> MS Name/IP address Stratum Poll Reach LastRx Last sample
>> ============================================================
>> ===================
>> #? NMEA 0 4 377 11 +3819us[+3819us] +/-
>> 106ms
>> #* PPS 0 4 377 12 +417ns[ +732ns] +/-
>> 1042ns
>>
>> Only reason I can think of is that /dev/pps0 isn't there yet at the time
>> systemd
>> starts chronyd. Thoughts?
>>
>
> Yup, that is what I think.
>
>
>>
