Re: [RFC][PATCH 0/3] PM: Asynchronous suspend and resume

[Alan Stern]

On Wed, 12 Aug 2009, Rafael J. Wysocki wrote:

> Hi,
> 
> The following patches introduce a mechanism allowing us to execute device
> drivers' suspend and resume callbacks asynchronously during system sleep
> transitions, such as suspend to RAM.  The idea is explained in the [1/1] patch
> message.
> 
> Comments welcome.

I get the idea.  Not bad.  Have you tried it in a serious way?  For 
example, turning on the async_suspend flag for every device?

In one way it isn't as efficient as it could be.  You fire off a bunch
of async threads and then make many of them wait for parent or child
devices.  They could be doing useful work instead.

It would be interesting to invent a way of representing explicitly the 
non-tree dependencies -- assuming there aren't too many of them!  (I 
can just hear the TI guys hollering about power and timer domains...)

Alan Stern

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