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Subject: Re: [linux-pm] [PATCH 1/8] PM: Add suspend block api.
From: Daniel Walker <dwalker@fifo99.com>
To: Matthew Garrett <mjg@redhat.com>
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Date: Fri, 07 May 2010 14:30:20 -0700
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On Fri, 2010-05-07 at 22:03 +0100, Matthew Garrett wrote:

> Here's a different example. A process is waiting for a keypress, but 
> because it's badly written it's also drawing to the screen at 60 frames 
> per second and preventing the system from every going to idle. How do 
> you quiesce the system while still ensuring that the keypress will be 
> delivered to the application?

To me it's somewhat of a negative for suspend blockers. Since to solve
the problem you give above you would have to use a suspend blocker in an
asynchronous way (locked in an interrupt, released in a thread too)
assuming I understand your example. I've had my share of semaphore
nightmares, and I'm not too excited to see a protection scheme (i.e. a
lock) which allows asynchronous usage like suspend blockers. 

Daniel