Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752843Ab3IJP0e (ORCPT ); Tue, 10 Sep 2013 11:26:34 -0400 Received: from mail-oa0-f50.google.com ([209.85.219.50]:59423 "EHLO mail-oa0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752801Ab3IJP0c (ORCPT ); Tue, 10 Sep 2013 11:26:32 -0400 MIME-Version: 1.0 In-Reply-To: References: Date: Tue, 10 Sep 2013 20:56:31 +0530 Message-ID: Subject: Re: "cpufreq: fix serialization issues with freq change notifiers" breaks cpufreq too From: Viresh Kumar To: Guennadi Liakhovetski Cc: Greg KH , "Rafael J. Wysocki" , Linux Kernel Mailing List , "linux-arm-kernel@lists.infradead.org" , "linux-pm@vger.kernel.org" , "cpufreq@vger.kernel.org" , SH-Linux , Magnus Damm Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1695 Lines: 46 On 10 September 2013 20:42, Guennadi Liakhovetski wrote: > 4. reverted that commit, resolving a trivial conflict. Added a debug > output in __cpufreq_driver_target() of > > > if (cpufreq_disabled()) > return -ENODEV; > + pr_info("%s() %d\n", __func__, policy->transition_ongoing); > if (policy->transition_ongoing) > return -EBUSY; Are you sure this diff is on linux-next and not after the revert that you mentioned later in the mail? There is some locking introduced by my patch which I can't see in you diff.. > Built and booted, got > > cpufreq: __cpufreq_driver_target(): 1 > > printed out 4 times from the beginning. > > 5. tried > > echo powersave > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor > > the above output appeared 2 more times - no frequency change resulted. > > 6. reverted commit dceff5ce18801dddc220d6238628619c93bc3cb6, built booted > - cpufreq works again. > >> I am afraid you need to give us some more information on how it broke >> your stuff.. :) > > Hope the above is enough. A bit more would be helpful.. Can you add these debug prints to all the places where transition_ongoing is getting modified? with %s, __func__ to distinguish them better? That will make it a bit easy for me... Also, what's the configuration of your system? How many CPUs? And are all of them sharing clock? (I believe yes, as you are using cpufreq-cpu0).. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/