Re: [gpsd-users] SHM number changing on reconnect

[Zach LaCelle]

Hi Gary/Paul,

Apologies, I forgot to include environment info. I'm in Ubuntu 16.04, kernel 4.15.0-34-generic, with gpsd from the PPAs (3.15-2build1 is the version listed).

It looks like this happens in the following case:

* Boot with GPS receiver attached via USB

* Remove GPS receiver

* Re-attach GPS receiver

Result: SHM2 is the new place gpsd published

Note that when I booted without it plugged in, the problem does not occur: SHM0 remains the one used by gpsd.

I will try restarting gpsd on re-plug of device to see what happens; unfortunately it's raining here now so no dice today.

-Zach

On Wed, Sep 12, 2018 at 3:53 PM Paul Theodoropoulos <address@hidden> wrote:

On 9/12/18 08:21, Zach LaCelle wrote:

I have a GPS receiver connected over USB that, when GPSD boots, has the SHM timing interface as 0 (ntpshmmon puts out NTP0 as the source). However, when I unplug and replug the device, Iget SHM 2 (ntpshmmon puts out NTP2). All future replugs are at NTP2.

How can I get GPSD to stay consistent with the SHM it writes to? I only have one receiver attached.

Does this happen even after a restart of GPSD? My thinking would be that if GPSD is running at the time you unplug, GPSD may consider SHM0 still in use, so then it assigns it to the next available SHM interface (SHM1 being already reserved for PPS1?)

Just a thought.

-- 
Paul Theodoropoulos
www.anastrophe.com