Re: Attempted summary of suspend-blockers LKML thread

From: david
Date: Thu Aug 05 2010 - 10:24:29 EST

On Thu, 5 Aug 2010, Matthew Garrett wrote:

On Wed, Aug 04, 2010 at 06:02:28PM -0700, Arve Hj?nnev?g wrote:

Which makes the driver and/or network stack changes identical to using
wakelocks, right?

I think we're resigned to the fact that we need to indicate wakeup
events in a manner that's pretty equivalent to wakelocks. The only real
issue is what the API looks like. Anyone who's still talking about
cgroups seems to be trying to solve a different problem.

Ok, it is now sounding to me like there are two different (but somewhat related) purposes that wakelocks are being used for

1. deciding if the system should go to sleep now or not (what most of the discussion has been about)

2. narrowing the race between going to sleep and wakeup events.

I'm not sure it's possible to completely eliminate the race, even with wakelocks there is some time between the time you last check if the wakelock is set and when the hardware finishes responding to your commands to go to sleep (Unless you can set a level-based interrupt that will wake you up as soon as you finish going to sleep)

David Lang
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