Re: [gpsd-users] Changing the GPS update rate with gpsd

[Deven Hickingbotham]

On 3/13/2016 8:30 AM, Bernd Büchs wrote:
> Well, I don't have Pi's or the exact GPS device you are using. From the
> Adafruit Homepage "Please note, this HAT takes over the Pi's hardware UART to
> send/receive data to and from the GPS module." so I would expect some problem
> here coming from different versions of gpsd and Linux...
>
> I usually stop the gpsd service and do the echo stuff on the console to
> /dev/ttyS5 in my case and after that I restart it. Since my Adafruit GPS
> defaults to 9600 baud I also need to reprogram the serial data speed of the
> GPS and device /dev/ttS5 itself using stty command. As last step I configure
> 5Hz/1Hz data output. I experienced that not every echo (especially
> reprogramming the baud-rate) is honored by the device, most of the time I try
> it several times.
>
> If you do it similar I don't see a direct hardware/software version
> dependency. The only point I suspect - but again I don't have a Pi - is that
> the /dev/ttyAMA0 is not or does not behave identical in both Linux versions.
> May be you require a fitting kernel module for getting "/dev/ttyAMA0". May be
> Adafruit can help here?

You may be correct on the kernel issue.

However, my thinking was that on both Wheezie and Jessie I can change 
the GPS update rate.  I wrote a Python app that does this and I can see 
the confirmation response code and see the packets speed up or slow 
down.  All of this is done through /dev/ttyAMA0.  It is only when I 
restart gpsd that things go wrong under Jessie and 3.11.  So my 
suspicion was that gpsd might be now resetting the GPS in 3.11.

I have posted this question on the Adafruit forums, but so far just 
silence.  That is why I headed over here to see if it may be gpsd related.