From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Tseng Subject: Re: ARM suspend to disk? Date: Mon, 03 May 2010 01:11:25 -0400 Message-ID: <4BDE5AFD.9070506@gmail.com> References: <4BD881A7.2020402@gmail.com> <87y6g6w373.fsf@deeprootsystems.com> <87iq78d295.fsf@deeprootsystems.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-vw0-f46.google.com ([209.85.212.46]:38331 "EHLO mail-vw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752491Ab0ECFLP (ORCPT ); Mon, 3 May 2010 01:11:15 -0400 Received: by vws19 with SMTP id 19so1459533vws.19 for ; Sun, 02 May 2010 22:11:14 -0700 (PDT) In-Reply-To: Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "Shilimkar, Santosh" Cc: Kevin Hilman , Cliff Brake , "linux-omap@vger.kernel.org" On 05/01/2010 03:12 AM, Shilimkar, Santosh wrote: >> -----Original Message----- >> From: linux-omap-owner@vger.kernel.org [mailto:linux-omap-owner@vger.kernel.org] On Behalf Of Kevin >> Hilman >> Sent: Saturday, May 01, 2010 3:36 AM >> To: Cliff Brake >> Cc: Peter Tseng; linux-omap@vger.kernel.org >> Subject: Re: ARM suspend to disk? >> >> Cliff Brake writes: >> >>> On Thu, Apr 29, 2010 at 1:58 PM, Kevin Hilman >>> wrote: >>> >>>> What do you expect to gain from suspend-to-disk + snapshot boot that >>>> you don't already get from suspend-to-RAM using off-mode? >>>> >>>> On OMAP, with off-mode enabled, a suspend to RAM puts the entire OMAP >>>> into full-chip off, and essentially reboots the ARM when waking up >>>> from suspend (or idle) already. >>> >>> What does the resume process look like in off mode? Does the resume >>> pass through the bootloader? If so, are the bits that detects resume >>> from "off" available in U-boot? >> >> No, it does not pass through the boot loader. >> >> In general terms, resume from off-mode is the same to "normal" resume (from >> retention) except that some additional state has to be restored before >> continuing where you left off since the ARM core (as well as most the >> OMAP itself) was turned off. >> > On suspend to disk topic, Raghu under Romit's guidance did a > prototype few months back as part of his internship using some of the earlier > ARM work. The whole system snapshot was stored to the MMC card and one > can take that MMC card on another board and continue from where it was suspended. > > We should have these patches somewhere. > It would be interesting to see these. Are you able to find these patches somewhere? Peter