From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755522AbbA2QEF (ORCPT ); Thu, 29 Jan 2015 11:04:05 -0500 Received: from m50-111.126.com ([123.125.50.111]:44755 "EHLO m50-111.126.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750840AbbA2QEC (ORCPT ); Thu, 29 Jan 2015 11:04:02 -0500 From: Xunlei Pang To: linux-kernel@vger.kernel.org Cc: rtc-linux@googlegroups.com, Thomas Gleixner , Alessandro Zummo , John Stultz , Arnd Bergmann , Xunlei Pang Subject: [PATCH v3 1/2] time: Don't bother to run rtc_resume() for the nonstop clocksource Date: Thu, 29 Jan 2015 23:59:06 +0800 Message-Id: <1422547147-3073-1-git-send-email-xlpang@126.com> X-Mailer: git-send-email 1.9.1 X-CM-TRANSID: jtKowAAnFg_qWMpUTaANDQ--.1799S2 X-Coremail-Antispam: 1Uf129KBjvJXoWxGr4xGr4DAr48Aw4UJF4xZwb_yoWrCFWDpr Wak343KFZrXF15uwnFv3ZruryYqws5KFW7JFyfCryIkry8Xan7GF1F93y5JryUurZ7Aw1j vF18tw45ur4UXrDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07jPuc_UUUUU= X-Originating-IP: [210.21.223.3] X-CM-SenderInfo: p0ost0bj6rjloofrz/1tbigRKQv1E0bBuoLgAAso Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Xunlei Pang If a system does not provide a persistent_clock(), the time will be updated on resume by rtc_resume(). With the addition of the non-stop clocksources for suspend timing, those systems set the time on resume in timekeeping_resume(), but may not provide a valid persistent_clock(). This results in the rtc_resume() logic thinking no one has set the time and it then will over-write the suspend time again, which is not necessary and only increases clock error. So, fix this for rtc_resume(). Signed-off-by: Xunlei Pang --- v2->v3: Refine according to John's comments using internal variable. drivers/rtc/class.c | 2 +- include/linux/timekeeping.h | 1 + kernel/time/timekeeping.c | 32 ++++++++++++++++++++------------ 3 files changed, 22 insertions(+), 13 deletions(-) diff --git a/drivers/rtc/class.c b/drivers/rtc/class.c index 472a5ad..6100af5 100644 --- a/drivers/rtc/class.c +++ b/drivers/rtc/class.c @@ -102,7 +102,7 @@ static int rtc_resume(struct device *dev) struct timespec64 sleep_time; int err; - if (has_persistent_clock()) + if (timekeeping_sleeptime_injected()) return 0; rtc_hctosys_ret = -ENODEV; diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h index 9b63d13..17a460d 100644 --- a/include/linux/timekeeping.h +++ b/include/linux/timekeeping.h @@ -225,6 +225,7 @@ static inline void timekeeping_clocktai(struct timespec *ts) /* * RTC specific */ +extern bool timekeeping_sleeptime_injected(void); extern void timekeeping_inject_sleeptime64(struct timespec64 *delta); /* diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 6a93185..b02133e 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1125,12 +1125,26 @@ static void __timekeeping_inject_sleeptime(struct timekeeper *tk, tk_debug_account_sleep_time(delta); } +static bool sleeptime_inject; + +#if defined(CONFIG_RTC_CLASS) && \ + defined(CONFIG_PM_SLEEP) && \ + defined(CONFIG_RTC_HCTOSYS_DEVICE) +/** + * Used by rtc_resume(). + */ +bool timekeeping_sleeptime_injected(void) +{ + return sleeptime_inject; +} + /** * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values * @delta: pointer to a timespec64 delta value * * This hook is for architectures that cannot support read_persistent_clock - * because their RTC/persistent clock is only accessible when irqs are enabled. + * because their RTC/persistent clock is only accessible when irqs are enabled, + * and also don't have an effective nonstop clocksource. * * This function should only be called by rtc_resume(), and allows * a suspend offset to be injected into the timekeeping values. @@ -1140,13 +1154,6 @@ void timekeeping_inject_sleeptime64(struct timespec64 *delta) struct timekeeper *tk = &tk_core.timekeeper; unsigned long flags; - /* - * Make sure we don't set the clock twice, as timekeeping_resume() - * already did it - */ - if (has_persistent_clock()) - return; - raw_spin_lock_irqsave(&timekeeper_lock, flags); write_seqcount_begin(&tk_core.seq); @@ -1162,6 +1169,7 @@ void timekeeping_inject_sleeptime64(struct timespec64 *delta) /* signal hrtimers about time change */ clock_was_set(); } +#endif /** * timekeeping_resume - Resumes the generic timekeeping subsystem. @@ -1178,8 +1186,8 @@ static void timekeeping_resume(void) struct timespec64 ts_new, ts_delta; struct timespec tmp; cycle_t cycle_now, cycle_delta; - bool suspendtime_found = false; + sleeptime_inject = false; read_persistent_clock(&tmp); ts_new = timespec_to_timespec64(tmp); @@ -1226,13 +1234,13 @@ static void timekeeping_resume(void) nsec += ((u64) cycle_delta * mult) >> shift; ts_delta = ns_to_timespec64(nsec); - suspendtime_found = true; + sleeptime_inject = true; } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) { ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time); - suspendtime_found = true; + sleeptime_inject = true; } - if (suspendtime_found) + if (sleeptime_inject) __timekeeping_inject_sleeptime(tk, &ts_delta); /* Re-base the last cycle value */ -- 1.9.1