Re: [gpsd-dev] Best way to avoid systemd woes for NTP?

[Greg Troxel]

"Gary E. Miller" <address@hidden> writes:

>> 2) The example gives a chrony line for sequencing, but not ntpd.  The
>> ham remix at least uses ntpd, so it seems both should be present.  Is
>> this a correct conclusion?
>
> No.  chrony OR ntpd.  Both try to use the NTP udp port and the SHM.
> Either will work for you.  Obviously we prefer NTPsec here.

I meant the lines that control ordering for systemd.  It seems there
should be one rule for the ordering of chrony/gpsd and one for
ntpd/gpsd, basically the same.

>> 3) The example in the troubleshooting page does not pass a tty
>> pathname, so I'm guessing that the udev/hotplug scripts are separate
>> from the systemd part, and arrange to call gpsdctl to add the tty on
>> insert.
>
> Yes.  As documented in the gpsd source.  Look at gpsd.rules for the
> udev rules to make the magic happen.

Thanksfor the pointer.

>> Is this known/expected to work on Ubuntu?
>
> Yes, known to work, badly documented.

It is being flaky for me.

>> 4) Does the -n flag for the global gpsd become effective on individual
>> serial ports added with gpsdctl?  If gpsd is started with no devices,
>> and hotplug does gpsdctl add, does gpsd start running on the new
>> device?
>
> I suspect starting gpsd with -n would then keep any hotplu agged GPS
> running all the time.  Worth testing.

Seems to.

>> 5) I don't follow how the default setup works, in that the hotplug
>> script should run on insert, and then gpsd only started when someone
>> starts a client.  So with the following sequence:
>> 
>>   1) boot
>>   2) systemd starts listening on 2947, no gpsd
>>   3) USB GPS mouse inserted
>>   4) user runs xgps
>>   5) systemd receives connection, starts up gpsd
>
> Step 3a) systemd starts gpsd.  

Because of some hotplug stuff?  So systemed starts gpsd on either a
hotplug insert, or on a connection to 2947?

> Step 3b) systemd can use -F, or gpsctl, to add the GPS.

> For those stuck on Ubuntu, most start out trying to get systemd to
> work.  Some succeed.  The rest get mad, delete the systemd/gpsd service,
> then start gpsd with a bootup script that uses -F and udev.

By this point, that does not seem surprising...