ubuntu-phone team mailing list archive

[Sam Bull <sam.hacking@xxxxxxxx>]

On Fri, 2015-11-27 at 15:28 +0100, Thomas Voß wrote:
> Whenever the phone goes to deep sleep (that is, it is suspended in your pocket),
> the GPS also switches off. It is one of the main parts of the system
> draining power.
> The behavior is intended at this point in time, though. We are working
> on enabling apps
> to selectively tell us that they are actively carrying out navigation
> tasks to prevent the device
> from going to deep sleep, though.

I've used uNav for navigating while walking, and suspending the phone
was not an issue. It would get a new fix and update the map after only a
few seconds of turning the phone back on. I see it only needing to keep
GPS active if the app is also providing voice navigation while the phone
is locked.

The one case it should handle, independent of any app, is if a GPS fix
is requested, and then the phone is locked, it should complete the GPS
fix. If it takes 20 mins to get a (cold-start, offline) GPS fix, and I
keep checking the phone to see if it has a fix and then locking it
again, it could go on for hours without ever getting a fix. So, as long
as there are still satellites visible (i.e. as long as I've not walked
into a building), the phone should complete the fix before it disables
GPS.

I think this would not only make it more reliable to users who don't
know how the system works. But, it would also save battery by not
requiring us to sit there with the screen on for no other reason than to
keep the GPS awake.

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