From owner-freebsd-acpi@FreeBSD.ORG Sat Sep 10 12:50:25 2005 Return-Path: X-Original-To: freebsd-acpi@freebsd.org Delivered-To: freebsd-acpi@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A2DED16A41F for ; Sat, 10 Sep 2005 12:50:25 +0000 (GMT) (envelope-from ducrot@poupinou.org) Received: from poup.poupinou.org (poup.poupinou.org [195.101.94.96]) by mx1.FreeBSD.org (Postfix) with ESMTP id 4E6E843D45 for ; Sat, 10 Sep 2005 12:50:25 +0000 (GMT) (envelope-from ducrot@poupinou.org) Received: from ducrot by poup.poupinou.org with local (Exim) id 1EE4oC-00068R-00; Sat, 10 Sep 2005 14:50:16 +0200 Date: Sat, 10 Sep 2005 14:50:16 +0200 To: Pranav Peshwe Message-ID: <20050910125016.GB23416@poupinou.org> References: <20050910125648.0267f124@localhost> <008101c5b601$9a2621e0$0201a8c0@pranav> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <008101c5b601$9a2621e0$0201a8c0@pranav> User-Agent: Mutt/1.5.9i From: Bruno Ducrot Cc: freebsd-acpi@freebsd.org Subject: Re: Does FBSD support 'software suspend' ? X-BeenThere: freebsd-acpi@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: ACPI and power management development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 10 Sep 2005 12:50:25 -0000 On Sat, Sep 10, 2005 at 05:47:15PM +0530, Pranav Peshwe wrote: > >AFAIK "software suspend" does not equal to "suspend to RAM". > >There are two different "suspend to disk" modes. One is "software suspend" > >the other "BIOS suspend". The second needs help by the BIOS and a special > >formated slice, the first doesn't. > >FreeBSD supports "BIOS supend" if the hardware supports it, > >you can tell by checking hw.acpi.s4bios with sysctl. > >GNU/Linux supports software suspend for S4 as well, ATM FreeBSD doesn't. > > >Fabian > > Thanks for the info. > > So, what i surmise is that : the 'suspend to disk' feature in BSD is > currently h/w dependent i.e BSD does not have a 'software suspend' > feature like in linux provided by suspend2 (http://www.suspend2.net). > > How useful is this feature(s/w suspend) , if implemented ? It's architecture independant. For example, under Linux, software suspend work under amd64, which can't use APM nor APCI S4Bios. I've heard it work under apple computers too, though I never tested myself. > I am planning to > take up its development as my final year project.I have not decided for > final to take it up;any suggestions/remarks regarding its use and feasiblity > would be very very valuable in helping me to take the right decision. Well, you should also look at those I think: - DragonflyBSD, especially their implementation of process checkpointing (I must admit I've not looked at this too much though); - implementation of system suspend by system checkpointing under OpenSolaris. In case of OpenSolaris, it seems it is based upon software suspend under Linux, but to my eyes they have done a much cleaner implementation IMHO. BTW the licence of OpenSolaris do not allow direct integration to FreeBSD IIRC, but that give some insight about a possible design under our OS. Cheers, -- Bruno Ducrot -- Which is worse: ignorance or apathy? -- Don't know. Don't care.