From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: So, what's the status on the recent patches here? Date: Mon, 4 Sep 2006 11:12:40 +0200 Message-ID: <20060904091230.GL9991@elf.ucw.cz> References: <200609032300.k83N0uL6016830@olwen.urbana.css.mot.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: <200609032300.k83N0uL6016830@olwen.urbana.css.mot.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.osdl.org Errors-To: linux-pm-bounces@lists.osdl.org Cc: scott.preece@motorola.com, matthew.a.locke@comcast.net, linux-pm@lists.osdl.org List-Id: linux-pm@vger.kernel.org Hi! > | Really, I think that the "states" which are entered only after tasks are > | frozen should be considered as special and handled separately. > --- > = > My point is that if the only kernel interface is set-op(), then the code > in the kernel that implements set-op() is the thing that's going to > drive the details of suspending the system, just as it does today. The > abstraction at the kernel interface is about as simple as it can be and > all the policy issues are moved outside the kernel. > = > My question is whether there are aspects of suspending, other than > latency, that the policy manager would need to consider in deciding > whether to suspend or not. > = > Look at it this way. In one scheme the policy manager code is: > = > new_OP =3D select_transition(current_OP, decision_factors); > set_OP(new_OP); No, it would be = new_OP =3D select_transition(current_OP, decision_factors); if (new_OP =3D=3D SUSPEND) { setup wakeup events ... } set_OP(new_OP); > in the other the policy manager code is: > = > new_OP =3D select_transition(current_OP, decision_factors); > if (new_OP =3D=3D SUSPEND) > suspend(); > else > set_OP(new_OP); ... > The one question that I see as interesting on that score is whether the > policy decision to suspend is based on factors that are wholly different > than the factors that drive frequency/voltage changes. If that were the > case, then there would be no point to making the decisions in the same > place. Honestly, I'm not sure of the answer to that... I'm pretty sure decision to suspend is other factors. Remember most machines are non-functional during suspend. Pavel -- = (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html