From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752234AbbAVMCk (ORCPT ); Thu, 22 Jan 2015 07:02:40 -0500 Received: from mail-qc0-f170.google.com ([209.85.216.170]:48575 "EHLO mail-qc0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751299AbbAVMC0 (ORCPT ); Thu, 22 Jan 2015 07:02:26 -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 v2 3/3] time: clocksource: Add a comment to CLOCK_SOURCE_SUSPEND_NONSTOP Date: Thu, 22 Jan 2015 12:01:17 +0000 Message-Id: <1421928077-4698-3-git-send-email-pang.xunlei@linaro.org> X-Mailer: git-send-email 2.2.1 In-Reply-To: <1421928077-4698-1-git-send-email-pang.xunlei@linaro.org> References: <1421928077-4698-1-git-send-email-pang.xunlei@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When doing timekeeping_resume(), if the nonstop clocksource wraps back, "cycle_delta" will miss the wrap time. It's hard to determine the right CLOCKSOURCE_MASK(xxx) or something to add code for inspecting such behavior, and we don't have many existent nonstop clocksources, so just add a comment to indicate that if have this flag set, people are aware that this nonstop clocksource won't wrap back during system suspend/resume. Signed-off-by: Xunlei Pang --- include/linux/clocksource.h | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index abcafaa..8680189 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -207,6 +207,11 @@ struct clocksource { #define CLOCK_SOURCE_WATCHDOG 0x10 #define CLOCK_SOURCE_VALID_FOR_HRES 0x20 #define CLOCK_SOURCE_UNSTABLE 0x40 + +/* + * When setting this flag, you're also supposed to mean that it doesn't + * wrap back during system suspend/resume. See timekeeping_resume(). + */ #define CLOCK_SOURCE_SUSPEND_NONSTOP 0x80 #define CLOCK_SOURCE_RESELECT 0x100 -- 1.9.1