From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752493AbbKQMCW (ORCPT ); Tue, 17 Nov 2015 07:02:22 -0500 Received: from mga03.intel.com ([134.134.136.65]:22981 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751630AbbKQMCU (ORCPT ); Tue, 17 Nov 2015 07:02:20 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,307,1444719600"; d="scan'208";a="822089727" From: zhuo-hao.lee@intel.com To: Thomas Gleixner , John Stultz Cc: linux-kernel@vger.kernel.org, zhuohao.lee82@gmail.com Subject: [PATCH v3] alarmtimer: fix unexpected rtc interrupt when system resume from S3 Date: Tue, 17 Nov 2015 20:08:07 +0800 Message-Id: <1447762087-5417-1-git-send-email-zhuo-hao.lee@intel.com> X-Mailer: git-send-email 2.1.2 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: John Stultz Signed-off-by: Zhuo-hao Lee --- kernel/time/alarmtimer.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index 7fbba63..e840ed8 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 = { -- 2.1.2