From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH] implement pm_ops.valid for everybody Date: Thu, 22 Mar 2007 22:33:04 +0100 Message-ID: <200703222233.06146.rjw@sisk.pl> References: <200703221344.l2MDi2Q9007989@olwen.urbana.css.mot.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <200703221344.l2MDi2Q9007989@olwen.urbana.css.mot.com> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: "Scott E. Preece" Cc: alexey.y.starikovskiy@intel.com, ben@simtec.co.uk, linux-arm@lists.arm.linux.org.uk, dirk.behme@de.bosch.com, pavel@ucw.cz, johannes@sipsolutions.net, nico@cam.org, linux-pm@lists.linux-foundation.org, g.liakhovetski@gmx.de List-Id: linux-pm@vger.kernel.org On Thursday, 22 March 2007 14:44, Scott E. Preece wrote: > = > | From: "Rafael J. Wysocki" > | = > | On Wednesday, 21 March 2007 23:57, Pavel Machek wrote: > | > Hi! > | > = > | > > > Which is very much an indication of how weak ACPI is. It > | > > > doesn't contemplate typical SOC behavior, which have a wide > | > > > variety of system sleep states that leave the CPU on ... and > | > > > which may not even *have* (or need!) a "cpu off" state. > | > > > = > | > > > My own definition would be more like: the minimal RAM-based > | > > > power-saving system state is "standby". If the system > | > > > implements a deeper RAM-based system sleep state, that's "STR". > | > > = > | > > Hmmm, this leaves the decision how to call each state COMPLETELY to= the = > | > > implementor, doesn't it? > | > = > | > Is that a problem? If someone is clever enough to implement suspend, I > | > think we can trust them to name their states right. > | > = > | > (And trust me, we can flame them if not). > | > = > | > (Anyway, my definition would be "mem" =3D=3D RAM is powered, everythi= ng > | > else is down, except for devices needed for wakeup; "standby" =3D=3D > | > something is powered that can be powered down, we'll fix that in next= version). > | = > | I think we can define "standby" a bit more precisely. Something like: > | - processes are frozen, > | - devices are suspended, > | - nonboot CPUs are down (and in low powered states, if possible), > | - "system" devices may or may not be suspended, depending on the platfo= rm, > | - the boot CPU may or may not be in a low power state, depending on the= platform, > | - RAM is powered > | - wake up need not be BIOS-driven (main difference from "mem") > --- > = > I would be tempted to say that that last bullet is the distinguishing > characteristic - that you come back from standby by just continuing > where you left off, but you come back from StR by something akin to > booting. Yes, that's what I meant. Greetings, Rafael