From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Eugeny S. Mints" Subject: Re: nokia 770 [was Re: community PM requirements/issues and PowerOP] Date: Thu, 14 Dec 2006 00:56:24 +0300 Message-ID: <45807708.3090607@gmail.com> References: <20060914101704.GA17820@elf.ucw.cz> <457FEE17.8080806@gmail.com> <20061213210359.GC11843@elf.ucw.cz> <200612131332.58606.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: <200612131332.58606.david-b@pacbell.net> 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 To: David Brownell Cc: linux-pm@lists.osdl.org, matthew.a.locke@comcast.net, scott.preece@motorola.com, Pavel Machek , Amit Kucheria List-Id: linux-pm@vger.kernel.org David Brownell wrote: > On Wednesday 13 December 2006 1:03 pm, Pavel Machek wrote: >> On Wed 2006-12-13 15:12:07, Eugeny S. Mints wrote: >>> David Brownell wrote: >>>> On Tuesday 19 September 2006 11:25 am, Pavel Machek wrote: >>>>> Could you perhaps provide list of operating points for 770? It would >>>>> help understanding a bit, I'd say. >>>> If there was a followup here, I missed it ... >>>> >>>> ISTR that it doesn't use (formal) operating points, and that a lot of = the >>>> basic SOC power savings (vs powering off the display or wifi) come fro= m a >>>> different kind of mechanism entirely. Namely, a combination of dynamic >>>> tick with a modified system idle task, which enters one of the OMAP low >>>> power modes during those long periods between clock ticks or other irq= s. >>>> >>>> That's one of the standard power saving schemes used on OMAP1 platforms >>>> with Linux. >>> sample of reasonable operating points for OMAP1 platforms along with ap= propriate = >>> patches may be found at http://dynamicpower.sourceforge.net/dpm-omap.ht= ml > = > That's the old DPM stuff not any of the newer proposals right? > = > I thought the question was specifically what N770 used. > = > = >> Okay... so you have system with 4 different cpu speeds. That should be >> simple enough to get running using cpufreq, no need for complex >> operating points patches. > = > And OMAP1 does have cpufreq support. I believe that if I checked it out > I'd find that it's used on N770, as a good way to kick in low voltage > operation modes. > = > ... that's in addition to the reduced power idle, which didn't seem to > fit into the DPM framework in any obvious way. It fits. Omitting some details DPM allows to map/stick operating point to t= asks. = Mapping one of OMAP low power mode operating point to idle task does the jo= b. Eugeny > = > - Dave > =