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Subject: Re: [PATCH 1/8] PM: Opportunistic suspend support.
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Date: Wed, 26 May 2010 12:06:24 +0200
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On Wed, 2010-05-26 at 02:54 -0700, Arve Hjønnevåg wrote:
> 
> I'm not sure what you are proposing that we use instead. Both
> user-space and kernel code needs to block suspend. If we don't have
> suspend blockers in the kernel then user-space needs to poll when a
> driver blocks suspend by returning an error from its suspend hook. 

In particular I'm suggesting you ditch the /dev/suspend_block thing.

With a single suspend manager process that manages the suspend state you
can achieve the same goal.

When the suspend manager has a !0 busy-task count, it ensures the kernel
won't auto-suspend, when it again reaches a 0 busy-task count, it
re-instates the auto-suspend feature.

That's pretty much what that device would do too.

Ideally we would not do the auto-suspend thing at all and have
runtime-PM improved. Not running apps when they expect to run is like
the world turned upside down.

'Evil' apps could always report themselves as blocker anyway.