From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965637AbbLRVj3 (ORCPT ); Fri, 18 Dec 2015 16:39:29 -0500 Received: from mail-pa0-f49.google.com ([209.85.220.49]:34155 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965470AbbLRVj0 (ORCPT ); Fri, 18 Dec 2015 16:39:26 -0500 From: John Stultz To: lkml Cc: zhuo-hao , Thomas Gleixner , Ingo Molnar , Miroslav Lichvar , Prarit Bhargava , Richard Cochran , John Stultz Subject: [PATCH 02/11] alarmtimer: Avoid unexpected rtc interrupt when system resume from S3 Date: Fri, 18 Dec 2015 13:39:07 -0800 Message-Id: <1450474756-10144-3-git-send-email-john.stultz@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1450474756-10144-1-git-send-email-john.stultz@linaro.org> References: <1450474756-10144-1-git-send-email-john.stultz@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: zhuo-hao Before the system go to suspend (S3), if user create a timer with clockid CLOCK_REALTIME_ALARM/CLOCK_BOOTTIME_ALARM and set a "large" timeout value to this timer. The function alarmtimer_suspend will be called to setup a timeout value to RTC timer to avoid the system sleep over time. However, if the system wakeup early than RTC timeout, the RTC timer will not be cleared. And this will cause the hpet_rtc_interrupt come unexpectedly until the RTC timeout. To fix this problem, just adding alarmtimer_resume to cancel the RTC timer. This was noticed because the HPET RTC emulation fires an interrupt every 16ms(=1/2^DEFAULT_RTC_SHIFT) up to the point where the alarm time is reached. This program always hits this situation (https://lkml.org/lkml/2015/11/8/326), if system wake up earlier than alarm time. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Miroslav Lichvar Cc: Prarit Bhargava Cc: Richard Cochran Signed-off-by: Zhuo-hao Lee [jstultz: Tweak commit subject & formatting slightly] Signed-off-by: John Stultz --- kernel/time/alarmtimer.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index 7fbba635..e840ed86 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -271,11 +271,27 @@ static int alarmtimer_suspend(struct device *dev) __pm_wakeup_event(ws, MSEC_PER_SEC); return ret; } + +static int alarmtimer_resume(struct device *dev) +{ + struct rtc_device *rtc; + + rtc = alarmtimer_get_rtcdev(); + if (rtc) + rtc_timer_cancel(rtc, &rtctimer); + return 0; +} + #else static int alarmtimer_suspend(struct device *dev) { return 0; } + +static int alarmtimer_resume(struct device *dev) +{ + return 0; +} #endif static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type) @@ -800,6 +816,7 @@ out: /* Suspend hook structures */ static const struct dev_pm_ops alarmtimer_pm_ops = { .suspend = alarmtimer_suspend, + .resume = alarmtimer_resume, }; static struct platform_driver alarmtimer_driver = { -- 1.9.1