systemd and GPSD issue

[Robert Livingston]

We have used the various versions of GPSD for 15 years but have a problem with Debian 11 that relates to socket conflicts (?).

The receivers are Trimble SMT 360 which appear to operate normally regarding both serial-getty and GPSD services (see #1 and 2 below). However, cgps displays only an initial page, and indicates no serial data flow.

Running GPSD from command line (#4) shows that socket conflicts are maybe the issue (#3 shows the sockets).

I apologize if this is a dumb request, but someone must have had the same problem. Any suggestions are welcome.

     #1. root@scionhfr2:/home/control# systemctl status serial-getty@ttyS0.service
    ● serial-getty@ttyS0.service
    - Serial Getty on ttyS0
         Loaded: loaded (/etc/systemd/system/serial-getty@ttyS0.service;
    enabled; v>
         Active: active (running) since Thu 2023-07-13 00:11:01 UTC; 1h
    7min ago
    ...    
    Jul 13 00:11:01 scionhfr2 systemd[1]: Started Serial Getty on ttyS0.
    
     #2. root@scionhfr2:/home/control# systemctl status gpsd
    ● gpsd.service - GPS (Global Positioning System) Daemon
         Loaded: loaded (/lib/systemd/system/gpsd.service; enabled;
    vendor preset: >
         Active: active (running) since Thu 2023-07-13 01:22:13 UTC; 31s
    ago…
    Jul 13 01:22:13 scionhfr2 systemd[1]: Starting GPS (Global
    Positioning System) >
    Jul 13 01:22:13 scionhfr2 systemd[1]: Started GPS (Global
    Positioning System) D>
    
    #3. root@scionhfr2:/home/control# sudo lsof -i -P -n | grep LISTEN
    systemd      1    root   66u  IPv6  18338      0t0  TCP [::1]:2947
    (LISTEN)
    systemd      1    root   67u  IPv4  18340      0t0  TCP
    127.0.0.1:2947 (LISTEN)
    anydesk    636    root   32u  IPv4  11008      0t0  TCP *:7070
    (LISTEN)
    sshd       680    root    3u  IPv4  13107      0t0  TCP *:22
    (LISTEN)
    sshd       680    root    4u  IPv6  13109      0t0  TCP *:22
    (LISTEN)
    cupsd      703    root    6u  IPv6  11751      0t0  TCP [::1]:631
    (LISTEN)
    cupsd      703    root    7u  IPv4  11752      0t0  TCP
    127.0.0.1:631 (LISTEN)
    gpsd      7311    gpsd    4u  IPv6  18338      0t0  TCP [::1]:2947
    (LISTEN)
    gpsd      7311    gpsd    5u  IPv4  18340      0t0  TCP
    127.0.0.1:2947 (LISTEN)
    
    #4. root@scionhfr2:/home/control# /sbin/gpsd -D 5 -N -n /dev/ttyS0
    gpsd:INFO: launching (Version 3.22)
    gpsd:IO: opening IPv4 socket
    gpsd:ERROR: can't bind to IPv4 port gpsd, Address already in use
    gpsd:ERROR: maybe gpsd is already running!
    gpsd:IO: opening IPv6 socket
    gpsd:ERROR: can't bind to IPv6 port gpsd, Address already in use
    gpsd:ERROR: maybe gpsd is already running!
    gpsd:ERROR: command sockets creation failed, netlib errors -1