RE: Problems with miss-behaving uBlox Module

[Neustifter Andreas]

HI Gary,

> From: gpsd-dev <gpsd-dev-bounces+andreas.neustifter=kapsch.net@nongnu.org> On 
> Behalf Of Gary E. Miller - Sent: Montag, 29. März 2021 20:27
>
> Yo Neustifter!
Andreas is fine...

> On Mon, 29 Mar 2021 17:49:36 +0000
> Neustifter Andreas <Andreas.Neustifter@kapsch.net> wrote:
>
> > we experienced windows of about 5-7 seconds where no data from GPSd
> > (via the IP interface at port 2947) was received when GPSd is
> > connected to our uBlox (NEO M8N, SPG 3.01, EXT CORE 3.01 (107900),
> > Protocol 18.00) modules.
>
> Ouch.
>
> What gpsd version?  How was it built?

Sorry, should have mentioned that: it's a 3.21, cross compiled for x86 on a 
64-bit Debian 9 with custom RTCM packet handling. No modifications to the 
parsing though.

> > After investigations with strace we found that the UBX-NAV-PVT message
> > sometimes reports a length of zero. This leads to the lexer not
> > working and the lexer-buffer filling up until an error occurs and the
> > buffer is reset. Attached a strace output of an offending message.
>
> The lexer should be able to handle UBX lenght zero.  Can you provide a serial
> capture of the u-blox binary stream doing that?

How would you like me to do that? The device is connected via USB on a tty, 
unfortunately this only happens with an update rate of at least 5 Hz and then 
only seldomly. Providing a full trace might not be that useful.

> > We currently believe this to be a bug in the firmware of our modules
> > but are checking with uBlox.
>
> Good luck with that.  AFAIK the sum mtotal of bugs they acknowledged from
> gpsd users is one.

Thanks.

> > Has anyone else experienced this kind of issues?
>
> Not me.

Yes I figured, couldn't find anything so I thought it doesn't hurt to ask.

> > The information contained in this e-mail message is privileged and
> > confidential and is for the exclusive use of the addressee.
>
> Seriously?  You know this is a public email list with public archives?

Seriously? Do we have to do this song-and-dance every time I post to this 
mailing list? You know that this is automatically attached by the mail server, 
is boilerplate and I can't remove it?

Andreas



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