Re: [gpsd-users] After RELEASE_TIME device closed, gpsd reports error on next open

[Gary E. Miller]

Yo Bin!

On Thu, 5 Sep 2019 21:31:21 +0000
Bin Guo <address@hidden> wrote:

>   Sorry for the long post.

It can be better than trying to slowly extract the data on your issue.

> This is my first time using gpsd.  I was
> trying to talk to a U-Box NEO-M8T via UART (no antenna yet, so no
> fix). Initially connecting with gpspipe, I can see gpsd switched
> driver to ubox:

Not gonna see much with no antenna.

> root@5gsb:~# /usr/sbin/gpsd -F /var/run/gpsd.sock -P
> /var/run/gpsd.pid /dev/ttyPS1 -N 

Why are you doing that?

Why use "-F /var/run/gpsd.sock" and "/dev/ttyPS1"?

One or the other.

Why are you not using "-n"?  You should always use "-n" unless you
are on battery and power is very important.

What kind of port is /dev/PS1?

>                 root@5gsb:~# gpspipe -r -n 10

[...]
All normal.

>  But after idle timeout:

If you used "-n" then you avoid idle timeout.  Otherwise gpsd has
to resync when a client connects.

[...]
> gpsd:PROG: device 0 closed

All normal because you did not use "-n".

> next gpspipe call shows that gpsd never gets back to UBX-... mode but
> gets stuck in a bad state:

That can happen, so use "-n" to avoid it.  Might be related to whatever
/dev/PS1 is.  How long did you wait?  resync can take minutes.

> gpsd:PROG: xPGSV: part 1 of 1, last_gsv_talker '0'  last_gsv_sigid 0
> gpsd:PROG: xPGSV: new part 1, last_gsv_talker '0', zeroing gpsd:WARN:
> xxGSV: Satellite data no good (1 of 1). gpsd:CLIENT: => client(0):

Sure looks like it finally did a resync.  All as expected so far.

> This can only be recovered by restarting gpsd

Looks normal to me.  Why did you think "recovery" was needed?

? (I did try ubx-tool -p RESET ... no help).

Yes, nothing to recover from.

> I compiled from git, but similar problems
> occurred for 3.16 and 3.19 releases.

Yes, looks like long term well known behavior so far.

> We might be able to poll gpsd more often, but this seems like a
> dangerous problem.

You never mentioned you client up til now.
Poll?  Don't poll, just wait for gpsd to send data.

If you only poll, with no "-n", then gpsd has to resync to the GPS every
request, which can be slow, then your app needs to resync to the JSON
stream.  All harder than just waiting on gpsd all the time.

> Is there anything apparent that I'm missing?

Always.

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

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

pgpl1PABRhSCQ.pgp
Description: OpenPGP digital signature