From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Eugeny S. Mints" Subject: Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?] Date: Tue, 12 Sep 2006 00:53:46 +0400 Message-ID: <4505CCDA.8020501@gmail.com> References: <450516E8.9010403@gmail.com> <20060911082025.GD1898@elf.ucw.cz> <20060911195546.GB11901@elf.ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20060911195546.GB11901@elf.ucw.cz> 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: Pavel Machek Cc: pm list , Preece Scott-PREECE List-Id: linux-pm@vger.kernel.org Pavel Machek wrote: > Hi! > = >> I know its confusing having oppoint (from Dave Singleton) and powerop = >> being discussed at the same time. However, I believe we (PowerOP) >> have = > = > Yes, it is. > = >> - PowerOP is only one layer (towards the bottom) in a power management = >> solution. >> - PowerOP does *not* replace cpufreq > = > PowerOP provides userland interface for changing processor > frequency. That's bad -- duplicate interface. Basically the biggest problem with cpufreq interface is that cpufreq has "c= hose predefined closest to a given frequency" functionality implemented in the kernel while there is _no_ any reason to have this functionality implemente= d in the kernel if we have sysfs interface exported by PowerOP in place - you ju= st _have_ to keep all possible functionality out of the kernel. CPufreq interf= ace is just subset of sysfs interface provided by PowerOP and _must_ be impleme= nted in userspace on top of sysfs interface - this is the proper way to scape duplication. Such issue with cpufreq<->kernel userspace interface is conseq= uence of the fact that cpufreq implements incorrect design of PM stack layers and interfaces. PowerOP solves this issues as well. > = >> - The PowerOP interface was discussed in detail on this list and we = >> haven't heard any negative comments. > = > Eh? Was I on different list?vb dfgdfv > = >> - We are not advocating the integration with sleep states. We want to = >> get the PowerOP interface accepted and then we can build on it. > = > Good. > = >> We have a few more comments from Greg to take care of and we can add a = >> Documentation/ file. Then I think its time to get the PowerOP patches = >> in the queue for acceptance. Any comments about this? > = > Well, you'll only get good interface review when you have > Documentation/ , and it needs to go to lkml before it goes to any > queues. PM stack is too complex and heavy part to go in such pieces thru lkml. i ex= pect = all linux pm experts to be on this list Eugeny > Pavel > =