Date: Sat, 10 Sep 2005 14:50:16 +0200 From: Bruno Ducrot <ducrot@poupinou.org> To: Pranav Peshwe <pranavpeshwe@gmail.com> Cc: freebsd-acpi@freebsd.org Subject: Re: Does FBSD support 'software suspend' ? Message-ID: <20050910125016.GB23416@poupinou.org> In-Reply-To: <008101c5b601$9a2621e0$0201a8c0@pranav> References: <20050910125648.0267f124@localhost> <008101c5b601$9a2621e0$0201a8c0@pranav>
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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.
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