Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758327Ab3HIR2B (ORCPT ); Fri, 9 Aug 2013 13:28:01 -0400 Received: from smtp.codeaurora.org ([198.145.11.231]:44492 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753672Ab3HIR17 (ORCPT ); Fri, 9 Aug 2013 13:27:59 -0400 Date: Fri, 9 Aug 2013 10:27:57 -0700 From: Stephen Boyd To: Daniel Lezcano Cc: srinivas.kandagatla@st.com, S??ren Brinkmann , Russell King , Michal Simek , linux-kernel@vger.kernel.org, Stuart Menefy , John Stultz , Thomas Gleixner , linux-arm-kernel@lists.infradead.org Subject: Re: Enable arm_global_timer for Zynq brakes boot Message-ID: <20130809172757.GD14845@codeaurora.org> References: <51F97CE3.9030306@linaro.org> <15e19315-ce88-4d3c-bad9-0a37d9e52f6b@CO1EHSMHS007.ehs.local> <51F99747.4060901@linaro.org> <51FA9AE8.1060004@linaro.org> <1c83c081-60c6-49e3-a85c-f64dd5be0e60@CH1EHSMHS030.ehs.local> <51FA9F54.3060704@linaro.org> <5204C54A.9020105@st.com> <5204FA5D.3060908@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5204FA5D.3060908@linaro.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2229 Lines: 59 On 08/09, Daniel Lezcano wrote: > > yes, but at least the broadcast mechanism should send an IPI to cpu0 to > wake it up, no ? As Stephen stated this kind of configuration should has > never been tested before so the tick broadcast code is not handling this > case properly IMHO. > If you have a per-cpu tick device that isn't suffering from FEAT_C3_STOP why wouldn't you use that for the tick versus a per-cpu tick device that has FEAT_C3_STOP? It sounds like there is a bug in the preference logic or you should boost the rating of the arm global timer above the twd. Does this patch help? It should make the arm global timer the tick device and whatever the cadence timer you have into the broadcast device. ---8<---- diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 218bcb5..d3539e5 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -77,6 +77,9 @@ static bool tick_check_broadcast_device(struct clock_event_device *curdev, !(newdev->features & CLOCK_EVT_FEAT_ONESHOT)) return false; + if (cpumask_equal(newdev->cpumask, cpumask_of(smp_processor_id()))) + return false; + return !curdev || newdev->rating > curdev->rating; } diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index 64522ec..1628b9f 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -245,6 +245,15 @@ static bool tick_check_preferred(struct clock_event_device *curdev, } /* + * Prefer tick devices that don't suffer from FEAT_C3_STOP + * regardless of their rating + */ + if (curdev && cpumask_equal(curdev->cpumask, newdev->cpumask) && + !(newdev->features & CLOCK_EVT_FEAT_C3STOP) && + (curdev->features & CLOCK_EVT_FEAT_C3STOP)) + return true; + + /* * Use the higher rated one, but prefer a CPU local device with a lower * rating than a non-CPU local device */ -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- 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/