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