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

[Martin Burnicki]

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.

Just an idea: According to the docs at
http://doc.ntp.org/current-stable/drivers/driver28.html

"The shared memory-segment is created with owner-only access by default,
unless otherwise requested by the mode word for units ≥2. Units 0 and 1
are always created with owner-only access for backward compatibility."

So maybe this depends on whether a program runs as root or a different
user, if it has dropped root privileges, or not, etc.

Martin