From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steve Muckle Subject: Re: sched-freq locking Date: Wed, 20 Jan 2016 17:39:14 -0800 Message-ID: <56A036C2.4090403@linaro.org> References: <56984C30.8040402@linaro.org> <569EE1E1.3050407@linaro.org> <2058083.HonoCMD469@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pa0-f51.google.com ([209.85.220.51]:36807 "EHLO mail-pa0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751028AbcAUBjR (ORCPT ); Wed, 20 Jan 2016 20:39:17 -0500 Received: by mail-pa0-f51.google.com with SMTP id yy13so13858201pab.3 for ; Wed, 20 Jan 2016 17:39:17 -0800 (PST) In-Reply-To: <2058083.HonoCMD469@vostro.rjw.lan> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Rafael J. Wysocki" Cc: Michael Turquette , Vincent Guittot , Juri Lelli , Patrick Bellasi , Morten Rasmussen , Dietmar Eggemann , Viresh Kumar , "linux-kernel@vger.kernel.org" , "linux-pm@vger.kernel.org" , Peter Zijlstra On 01/20/2016 05:22 PM, Rafael J. Wysocki wrote: > One comment here (which may be a bit off in which case please ignore it). > > You seem to be thinking that sched-freq needs to be a cpufreq governor > and thus be handled in the same way as ondemand, for example. That's true, I hadn't really given much thought to the alternative you mention below. > > However, this doesn't have to be the case in principle. For example, > if we have a special driver callback specifically to work with sched-freq, > it may just use that callback and bypass (almost) all of the usual > cpufreq mechanics. This way you may avoid worrying about the governor > locking and related ugliness entirely. That sounds good but I'm worried about other consequences of taking cpufreq out of the loop. For example wouldn't we need a new way for something like thermal to set frequency limits? thanks, steve