From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
To: Keerthy <a0393675@ti.com>
Cc: Keerthy <j-keerthy@ti.com>,
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
Date: Tue, 14 Jun 2016 16:39:48 +0200 [thread overview]
Message-ID: <20160614143948.GP3240@piout.net> (raw)
In-Reply-To: <575693E1.2090302@ti.com>
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
next prev parent reply other threads:[~2016-06-14 14:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-01 10:49 [PATCH] rtc: ds1307: Fix relying on reset value for weekday Keerthy
2016-06-01 12:18 ` Alexandre Belloni
2016-06-01 12:36 ` Keerthy
2016-06-07 9:29 ` Keerthy
2016-06-14 14:39 ` Alexandre Belloni [this message]
2016-06-15 4:14 ` Keerthy
2016-07-08 14:25 ` Alexandre Belloni
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