[2008.testing] GPS after resume
openmoko at mazikeen.demon.co.uk
Mon Jan 5 13:23:17 CET 2009
Yes, and I think ogpsd is supposed to do this. Almanac and ephemeris is saved
when preparing for suspend, and loaded on resume, along with current time. If
things haven't changed too much while suspend then resume should be faster
than from cold.
On Sunday 04 January 2009, Yorick Moko wrote:
> but would it not be possible to let the gps poweroff and artificially
> "feed" it the last known sattelite positions? so that i can get a
> hot-start after suspend, without using more power?
> anyway, thanks for your contribution!
> On Sun, Jan 4, 2009 at 11:17 AM, Vladimir Koutny <vlado at moko.ksp.sk> wrote:
> >> i was thinking about this the other day. the gps has it's own
> >> processor, correct, and can act independently of the cpu? i'm
> >> wondering if it's possible for the gps to keep it's fix while the main
> >> cpu is in suspend. power usage will be higher than a full suspend, but
> >> the phone will have a fix as soon as it resumes. is there any reason
> >> why this can't happen?
> > I wrote attached patch for this few days ago - it is against mwester's
> > stable kernel so probably still needs some tweaks for 2.6.28 series.
> > Simply 'echo 1 >
> > /sys/bus/i2c/devices/0-0073/neo1973-pm-gps.0/keep_on_in_suspend' and it
> > will stay alive during suspend (echo 0 to turn it off - this is also the
> > default).
> > It also fixes a bug with re-enabling GPS on resume when it was on before
> > (keep_on_in_suspend=0).
> > I'm going to split this into 2 patches and send it to devel soon.
> > vlado
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