From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751393AbcFNOkI (ORCPT ); Tue, 14 Jun 2016 10:40:08 -0400 Received: from down.free-electrons.com ([37.187.137.238]:39366 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751029AbcFNOkF (ORCPT ); Tue, 14 Jun 2016 10:40:05 -0400 Date: Tue, 14 Jun 2016 16:39:48 +0200 From: Alexandre Belloni To: Keerthy Cc: Keerthy , a.zummo@towertech.it, nm@ti.com, rtc-linux@googlegroups.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] rtc: ds1307: Fix relying on reset value for weekday Message-ID: <20160614143948.GP3240@piout.net> References: <1464778147-22075-1-git-send-email-j-keerthy@ti.com> <20160601121802.GF4249@piout.net> <574ED6D1.70800@ti.com> <575693E1.2090302@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <575693E1.2090302@ti.com> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/06/2016 at 14:59:05 +0530, Keerthy wrote : > Hi Alexandre, > > On Wednesday 01 June 2016 06:06 PM, Keerthy wrote: > > > > > > On Wednesday 01 June 2016 05:48 PM, Alexandre Belloni wrote: > > > Hi, > > > > > > On 01/06/2016 at 16:19:07 +0530, Keerthy wrote : > > > > The reset value of weekday is 0x1. This is wrong since > > > > the reset values of the day/month/year make up to Jan 1 2001. > > > > When computed weekday comes out to be Monday. On a scale > > > > of 1-7(Sunday - Saturday) it should be 0x2. So we should not > > > > be relying on the reset value. > > > > > > > > > > Hum, what are the chances that the reset value is actually the correct > > > date/time? > > > Won't that be corrected after the first call to set_time? Until then, > > > the date is not correct so, do we care anyway? > > > > Yes if an alarm is programmed without set_time. > > > > ex: rtcwake -d /dev/rtc0 -s 5 > > > > Even the basic rtctest under tools/testing/selftests/timers/rtctest.c fails > > as the wday is wrong and no alarm fires. > > > > Instead of relying on some one to call set_time before programming alarm > > its better to fix the wday to reflect the current day right? > > > > > > > > > > Maybe I'm missing something here. > > Let me know if you feel this is a valid fix. > Well, this is probably a valid fix and I'll take it as is if I don't find the time to make something more generic. -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com