From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Brownell <david-b@pacbell.net>
Subject: Re: [PATCH 2/2] Fix console handling during
	suspend/resume
Date: Fri, 16 Jun 2006 07:04:33 -0700
Message-ID: <200606160704.34093.david-b@pacbell.net>
References: <20060614103404.GC28536@elf.ucw.cz>
	<200606150957.42449.david-b@pacbell.net>
	<20060615180350.GG23859@elf.ucw.cz>
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To: Pavel Machek <pavel@ucw.cz>
Cc: Linus Torvalds <torvalds@osdl.org>, linux-pm@lists.osdl.org
List-Id: linux-pm@vger.kernel.org

On Thursday 15 June 2006 11:03 am, Pavel Machek wrote:

> > =

> > In this case, DMA only would need to be prevented during the actual
> > construction of the snapshot -- which is AFTER that "prepare to
> > suspend" phase, notice! -- so your straw-man doesn't apply.
> =

> Okay, you _can_ do =

> =

> suspend whole tree but disk and video
> freeze disk and video
> create snapshot
> unfreeze disk and video
> write snapshot
> powerdown
> =

> Question is: looks to me like quite a lot of complexity for very
> little gain, but...

It's not so different from what Linus has been sketching, except
for the actual turn-off-DMA step.  (Needed because you want to get
an atomic snapshot.)  In terms of $SUBJECT the gain is that you
actually get a debuggable suspend sequence.