From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sudeep Holla Subject: Re: [PATCH 16/20] sched/idle: Use explicit broadcast oneshot control function Date: Tue, 28 Apr 2015 11:42:44 +0100 Message-ID: <553F6424.1090704@arm.com> References: <2112147.0kYCHhbEJT@vostro.rjw.lan> <18575128.8R6Lp68k0Q@vostro.rjw.lan> <553F6236.5020300@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from foss.arm.com ([217.140.101.70]:58958 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933112AbbD1Kmr (ORCPT ); Tue, 28 Apr 2015 06:42:47 -0400 In-Reply-To: <553F6236.5020300@linaro.org> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Daniel Lezcano , Linus Walleij , "Rafael J. Wysocki" , Linux PM list , Thomas Gleixner Cc: Sudeep Holla , Peter Zijlstra , Ingo Molnar , Linux Kernel Mailing List , ACPI Devel Maling List On 28/04/15 11:34, Daniel Lezcano wrote: > On 04/28/2015 12:11 PM, Linus Walleij wrote: >> On Thu, Apr 2, 2015 at 12:22 AM, Rafael J. Wysocki >> wrote: >> >>> From: Thomas Gleixner >>> >>> Replace the clockevents_notify() call with an explicit function >>> call. >>> >>> Signed-off-by: Thomas Gleixner >>> Signed-off-by: Rafael J. Wysocki >> >> For some reason this makes my Ux500 system arbitrarily hang, >> especially during boot. Bisected down to this commit. Since the >> entire changeset is removing the notifications altogether I can't >> just revert it. >> >> Disabling CONFIG_CPU_IDLE removes the problem. >> >> Tried registering a stub driver (I just #if 0 all the code in >> drivers/cpuidle/cpuidle-ux500.c) it still crashes. >> >> That makes me think something inside the cpuidle subsystem is >> locking up after this, but my other idea is that the timer may be >> involved in some way, like this is stressing the timer in some new >> yet untested way. >> >> Has anyone else seen problems with this or is it only ux500? >> >> I'm looking closer at it but feel a bit clueless... > > If you keep the #if 0 and remove the CPUIDLE_FLAG_TIMER_STOP flag, > does it still crash ? > At-least I observed issue only when I am using hardware broadcast timer. It doesn't hang when I am using hrtimer as broadcast timer in which case one of the cpu will be not enter deeper idle states that lose timer. I will rerun on v4.1-rc1 and post the complete log. Regards, Sudeep