[Pm-utils] Canceling resume

[Dan Nicholson]

On Thu, Nov 19, 2009 at 1:13 AM, Enrico Zini <enrico at enricozini.org> wrote:
> Hello,
>
> I am investigating pm-utils as the glue to tie together suspend/resume
> machinery on the OpenMoko FreeRunner.
>
> One thing that is needed, and that I didn't manage to understand if it
> could be done with pm-utils, is to cancel a resume.
>
> There are various reasons why the phone can be set to resume: user
> request, receiving a phone call, a change of the fix on the GPS, a
> timer, an inbound GPRS data packet, possibly more.
>
> Not all of those events require the phone to fully unsuspend, turn on
> screen and so on and so forth. In the case of a GPS fix change, for
> example, the only thing needed would be to append some data to a GPX
> track log, then one can go to sleep again.
>
> It is possible to inspect the resume reason upon resume, so pm-utils
> scripts could check that, then decide if a full resume is needed or if
> the resume reason can be handled right away and then return to sleep.
>
> Is it possible for a resume script in pm-utils to say "Ok, I took care
> of it, don't bother running the rest, let's go back to sleep" ?

The bulk of the resume is handed in the kernel. pm-utils just adds a
little bit on top to pull it all together and has nothing to do with
actually resuming the hardware. If you really need to block a resume,
it should happen in the kernel. You could write a hook that
immediately suspends again, but it would be a pretty nasty user
experience.

--
Dan