From: Mark Salyzyn <salyzyn@android.com>
To: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: linux-kernel@vger.kernel.org,
Alessandro Zummo <a.zummo@towertech.it>,
rtc-linux@googlegroups.com
Subject: [rtc-linux] Re: rtc-palmas: correct for bcd year
Date: Tue, 5 Jan 2016 08:08:50 -0800 [thread overview]
Message-ID: <568BEA92.2090701@android.com> (raw)
In-Reply-To: <20160105000000.GE32724@piout.net>
On 01/04/2016 04:00 PM, Alexandre Belloni wrote:
> I'd say that the proper course of action is to refuse to set dates
> before 2000 and after 2100. See http://patchwork.ozlabs.org/patch/541037/
Got it.
We have an issue though, Android (or rather any embedded) devices must
continue to function when date is manually set to any value between 1970
and 2037. The issue here is a fresh device with a recently charged
battery will _start_ at 1970 until ntp or cell time/date/locale is set
and the device must continue to function in this vacuum. A device reboot
should not result in the other calendar values being reset, should the
year be wrong, as this will result in a bad user experience.
We will have to use a different patch on Android than upstream if dates
before 2000 are deprecated.
All other factors (rollover, leap) can be corrected by frameworks and
runtime since the rtc is generally secondary (ie: first rtc driver was
in 1979, created a daemon to correct the flaws in the hardware clock
using a cron job)
Sincerely -- Mark Salyzyn
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WARNING: multiple messages have this Message-ID (diff)
From: Mark Salyzyn <salyzyn@android.com>
To: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Cc: linux-kernel@vger.kernel.org,
Alessandro Zummo <a.zummo@towertech.it>,
rtc-linux@googlegroups.com
Subject: Re: rtc-palmas: correct for bcd year
Date: Tue, 5 Jan 2016 08:08:50 -0800 [thread overview]
Message-ID: <568BEA92.2090701@android.com> (raw)
In-Reply-To: <20160105000000.GE32724@piout.net>
On 01/04/2016 04:00 PM, Alexandre Belloni wrote:
> I'd say that the proper course of action is to refuse to set dates
> before 2000 and after 2100. See http://patchwork.ozlabs.org/patch/541037/
Got it.
We have an issue though, Android (or rather any embedded) devices must
continue to function when date is manually set to any value between 1970
and 2037. The issue here is a fresh device with a recently charged
battery will _start_ at 1970 until ntp or cell time/date/locale is set
and the device must continue to function in this vacuum. A device reboot
should not result in the other calendar values being reset, should the
year be wrong, as this will result in a bad user experience.
We will have to use a different patch on Android than upstream if dates
before 2000 are deprecated.
All other factors (rollover, leap) can be corrected by frameworks and
runtime since the rtc is generally secondary (ie: first rtc driver was
in 1979, created a daemon to correct the flaws in the hardware clock
using a cron job)
Sincerely -- Mark Salyzyn
next prev parent reply other threads:[~2016-01-05 16:08 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-30 20:51 [rtc-linux] rtc-palmas: correct for bcd year Mark Salyzyn
2015-12-30 20:51 ` Mark Salyzyn
2016-01-04 16:18 ` [rtc-linux] " Alexandre Belloni
2016-01-04 16:18 ` Alexandre Belloni
2016-01-04 16:45 ` [rtc-linux] " Mark Salyzyn
2016-01-04 16:45 ` Mark Salyzyn
2016-01-05 0:00 ` [rtc-linux] " Alexandre Belloni
2016-01-05 0:00 ` Alexandre Belloni
2016-01-05 16:08 ` Mark Salyzyn [this message]
2016-01-05 16:08 ` Mark Salyzyn
2016-07-08 14:10 ` [rtc-linux] " Alexandre Belloni
2016-07-08 14:10 ` Alexandre Belloni
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