From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933046AbXDZGp2 (ORCPT ); Thu, 26 Apr 2007 02:45:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933069AbXDZGp2 (ORCPT ); Thu, 26 Apr 2007 02:45:28 -0400 Received: from nigel.suspend2.net ([203.171.70.205]:53453 "EHLO nigel.suspend2.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933046AbXDZGp0 (ORCPT ); Thu, 26 Apr 2007 02:45:26 -0400 Subject: Re: suspend2 merge (was Re: [Suspend2-devel] Re: CFS and suspend2: hang in atomic copy) From: Nigel Cunningham Reply-To: nigel@nigel.suspend2.net To: Linus Torvalds Cc: Pavel Machek , Kenneth Crudup , Nick Piggin , Mike Galbraith , linux-kernel@vger.kernel.org, Thomas Gleixner , Con Kolivas , suspend2-devel@lists.suspend2.net, Ingo Molnar , Andrew Morton , Arjan van de Ven In-Reply-To: References: <20070419070437.GA25211@elte.hu> <20070424202336.GC16503@elf.ucw.cz> <20070424212408.GD16457@elf.ucw.cz> <20070425072350.GA6866@ucw.cz> <20070425202741.GC17387@elf.ucw.cz> <20070425214420.GG17387@elf.ucw.cz> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-xnLf079A8XArn3c0in3I" Date: Thu, 26 Apr 2007 08:27:07 +1000 Message-Id: <1177540027.5025.87.camel@nigel.suspend2.net> Mime-Version: 1.0 X-Mailer: Evolution 2.10.1 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --=-xnLf079A8XArn3c0in3I Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Hi. On Wed, 2007-04-25 at 15:18 -0700, Linus Torvalds wrote: >=20 > On Wed, 25 Apr 2007, Pavel Machek wrote: > >=20 > > Not the same... but they are still related. "freeze" (for atomic > > snapshot) is actually subset of "suspend"... freeze needs DMAs off and > > saved state, and you need DMAs off and saved state for "suspend". >=20 > THEY HAVE ABSOLUTELY NOTHING IN COMMON! >=20 > Nobody in their right mind thinks that "disable DMA" and "suspend" are=20 > similar operations.=20 >=20 > > So it is actually correct to do "suspend" when you want "freeze"; it > > is just slow. That's why they only differ in parameter these days. >=20 > It is *not* correct to "suspend" when you want "freeze". >=20 > I don't understand how you can even *claim* something like that. >=20 > Here's a trivial example: > - SCSI disk >=20 > Tell me, what does "suspend" do, and what does "freeze" (snapshot) do? >=20 > And name *one* thing that have in common. Set/reset the scsi transaction id thingy? Hibernation didn't work with SCSI for a long time precisely because that support was missing. Don't get me wrong, I agree on the whole - Suspend2 worked fine on the whole under 2.4 without a driver model. But they do have a bit in common. Regards, Nigel --=-xnLf079A8XArn3c0in3I Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQBGL9W7N0y+n1M3mo0RAp2aAKCBpvIPtjm7XShf2wf+XVxDF6a3CgCdG9kI bX+QQepHH4K75HqtylXurYM= =Q5BJ -----END PGP SIGNATURE----- --=-xnLf079A8XArn3c0in3I--