Re: Only one client at a time (Debian, Raspbian)

[Gary E. Miller]

Yo Carles!

On Wed, 28 Jul 2021 22:19:24 +0200
Carles Pina i Estany <carles@pina.cat> wrote:

> I have a Garmin eTrex 30x GPS connected using USB to either my
> computer (Debian Buster) or to a Raspberry pi (Buster as well).

I'm curious how you got any NMEA out of the eTrex.  Many people
report failure at that.

> I installed "gpsd" Debian package and then I'm trying to have two
> different software access the gpsd over the port TCP 2947:

I can't speak to the Debian package,  that is not from us.

> -kplex for reading it and saving into files / send NMEA string over
> the network

New one on me.  Why use it?

> -qgis (which doesn't have TCP NMEA alike but gpsd)

I do not understand that last bit: "(which doesn't have TCP NMEA alike
but gpsd)"

> I realise that gpsd 2947 port in Debian/Raspbian is handled by systemd
> socket activation (which I've never used before... so I might be
> missing something).

I also do not use systemd(umb), but I know it causes daily complaints
on this email list.

> As soon as one software (e.g. kplex) uses it, the other one (qgis)
> cannot use it.

I often connect multiple clients over port 2947 with no problem.  For
example: xgps, xgps and gpspipe all at the same time.

Can you connect two cgps?  Or one cgps and one xgps?

> If I do it using telnet:
> 
> Terminal 1:
> pi@raspberrypi:~ $ telnet localhost 2947
> Trying ::1...
> Connected to localhost.
> Escape character is '^]'.
> {"class":"VERSION","release":"3.17","rev":"3.17","proto_major":3,"proto_minor":12}

3.17 is ancient.  3.23 is to be releassed bext week.

> If I go to another terminal I don't get the welcome message:
> pi@raspberrypi:~ $ telnet localhost 2947
> Trying ::1...
> Connected to localhost.
> Escape character is '^]'.

Works for me on 3.22.  Could be your old version, could be the
debian package, or could be systemd(umbest).  I can't fix any of those.

> I've been trying to not have systemd and use just gpsd but I had other
> problems - that I can show step by step but hopefully not needed. I'm
> happy to fix what I have not to replace everything.

Remove gpsd fro systemd(rool), then just start gpsd normally, as root:
        gpsd -n /dev/ttyXX

> What I'm doing just work? Should I take another approach for my
> problem?

No idea, works for me.

> Using: gpsd 3.17-7+b1 (all from the distros at the moment, as I
> thought that is a common use case)

I hate to think using 4 year old software, with known CVE, is common.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        gem@rellim.com  Tel:+1 541 382 8588

            Veritas liberabit vos. -- Quid est veritas?
    "If you can't measure it, you can't improve it." - Lord Kelvin

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