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Subject: Re: [PATCH] Remove process freezer from suspend to RAM pathway
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>, Kyle Moffett <mrmacman_g4@mac.com>,
       Nigel Cunningham <nigel@nigel.suspend2.net>,
       Pavel Machek <pavel@ucw.cz>, Matthew Garrett <mjg59@srcf.ucam.org>,
       linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org
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Date: Mon, 09 Jul 2007 07:21:48 +1000
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On Sun, 2007-07-08 at 16:22 -0400, Alan Stern wrote:
> On Sun, 8 Jul 2007, Rafael J. Wysocki wrote:
> 
> > I'm all for changing this infrastructure, but in an organized way (ie. we
> > discuss what to do next, we do that and then we go to the next step) and in
> > the order that everyone will be comfortable with.
> > 
> > So, let's finish this thread and start over from discussing what needs to be
> > done, how (ie. in what order etc.) we are going to do that and who is going to
> > do what.  Shall we?
> 
> IMO we should start by using the new notifier chain and by implementing 
> a central "icebox" routine.  Then we can forbid device registration 
> during suspend.
> 
> It might also be a good idea to add a freezable keventd-like workqueue 
> specifically intended for things that need to block during a suspend.  
> Although maybe this will end up being unnecessary; it's too soon to 
> tell.

I think looking at the kmallo/gfp issue I mentioned earlier should be
done asap. I can try to spare some time for it this week but I can't
promise, I'm actually swamped by something totally unrelated at the
moment.

Another issue that's been a problem forever with suspend is the
synchronous request_firmware interface. Lots of drivers do that in
resume() which will generally not work.

Ben.