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From: Al Boldi <a1426z@gawab.com>
To: Alan Stern <stern@rowland.harvard.edu>
Subject: Re: Hibernation considerations
Date: Mon, 16 Jul 2007 19:51:35 +0300
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Cc: "Rafael J. Wysocki" <rjw@sisk.pl>, <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@linux-foundation.org>,
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Alan Stern wrote:
> On Mon, 16 Jul 2007, Al Boldi wrote:
> > From a kexec'd hibernation kernel pov, both S3 and S4 look conceptually
> > exactly the same.  The only difference is, in S3 the memory is in memory
> > and in S4 the memory is on storage.  All device handling is exactly the
> > same, so if there is a problem with device handling between the kexec'd
> > hibernation kernel and the normal kernel, then that would have made
> > itself visible.
>
> You have contradicted yourself.  "In S3 the memory is in memory and in
> S4 the memory is on storage".  How does the memory get onto storage?
> The kexec'd hibernation kernel writes it there.  To do so it accesses a
> storage device.
>
> Consequently the device handling _cannot_ be exactly the same in S3 and
> S4.

Ok, you should have read this in the context of suspending/resuming from/to 
the normal kernel, and in that case they are exactly the same, i.e. kexec -e 
for suspend and kexec -j for resume.

BTW, it would be really helpful if people would actually try the kexec 
hibernation patches, as this may yield a much more constructive discussion.


Thanks!

--
Al