From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH] implement pm_ops.valid for everybody Date: Fri, 23 Mar 2007 00:21:03 +0100 Message-ID: <200703230021.04470.rjw@sisk.pl> References: <200703221344.l2MDi2Q9007989@olwen.urbana.css.mot.com> <200703222310.39623.rjw@sisk.pl> <200703221556.08948.david-b@pacbell.net> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <200703221556.08948.david-b@pacbell.net> 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: David Brownell Cc: alexey.y.starikovskiy@intel.com, ben@simtec.co.uk, dirk.behme@de.bosch.com, pavel@ucw.cz, linux-pm@lists.linux-foundation.org, johannes@sipsolutions.net, nico@cam.org, g.liakhovetski@gmx.de List-Id: linux-pm@vger.kernel.org On Thursday, 22 March 2007 23:56, David Brownell wrote: > On Thursday 22 March 2007 3:10 pm, Rafael J. Wysocki wrote: > = > > Well, I think the only clear distinction between the STR and "standby" = is the > > necessity to go through a boot-like procedure in order to resume from t= he > > former. > = > So what's a "boot-like procedure"? Ten instructions? A hundred? > A thousand? Ten thousand? Does it take a certain amount of time? > Does it perform certain operations? Does it involve going through > ACPI (or APM)? If so, what about the fact that ACPI (or APM) are > involved in "standby" resumes too (on platforms using them)? > = > And why wouldn't a standby mode be able to do any or all of those? > = > = > > So, I'd tend to think the STR is when the CPU(s) is(are) powered = > > down and if some platforms don't support that, they just don't support = the > > STR. > = > That seems like a counterproductive restriction. The only reason to > adopt it is if you care so much about ACPI that you insist on using > their state definitions even on systems that will never use ACPI. > = > For a system that supports several power saving modes but doesn't > have the ability to turn the CPU off, what conceivable value would > there be in saying it's not OK to use the "STR" label for any of > those states? > = > And thus, to say that the system is only **allowed** to expose one > of those power saving modes to Linux ... and that it must always > be called "standby"? Even if, from an external perspective, it > acts just like an STR would act? > = > My answer: there is NO value to such an arbitrary restriction. I'm not talking on restrictions. I'm talking on being able to define _anything_ more precisely then just a low-power system-wide state. And let's start from just something, please. Like STR and "stadndby" to be= gin with? At least on ACPI systems we can distinguish one from the other quite clearly, so why can't we start from that and _then_ generalize? Rafael