From: Pavel Machek <pavel-+ZI9xUNit7I@public.gmane.org>
To: Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Cc: Alexandre Belloni
<alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>,
Russell King - ARM Linux
<linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org>,
Benjamin Gaignard
<benjamin.gaignard-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
Baruch Siach <baruch-NswTu9S1W3P6gbPvEgmw2w@public.gmane.org>,
"patches-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org"
<patches-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org>,
Linus Walleij
<linus.walleij-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
"linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Thierry Reding
<thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
"x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org"
<x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Jonathan Hunter
<jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>,
Chen-Yu Tsai <wens-jdAy2FN1RRM@public.gmane.org>,
Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
Sylvain Lemieux
<slemieux.tyco-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Sebastian Hesselbarth
<sebastian.hesselbarth-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Len Brown <len.brown-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
"linaro-kernel-cunTk1MwBs8s++Sfvej+rw@public.gmane.org"
<linaro-kernel-cunTk1MwBs8s++Sfvej+rw@public.gmane.org>,
Jason Cooper <jason-NLaQJdtUoK4Be96aLqz0jA@public.gmane.org>,
"rtc-linux-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org"
<rtc-linux-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org>,
"linux-pm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" <lin
Subject: Re: [PATCH 00/51] rtc: stop using rtc deprecated functions
Date: Wed, 21 Jun 2017 09:51:52 +0200 [thread overview]
Message-ID: <20170621075152.GA15996@amd> (raw)
In-Reply-To: <alpine.DEB.2.20.1706202343120.2157@nanos>
[-- Attachment #1: Type: text/plain, Size: 1867 bytes --]
Hi!
> > I agree with that but not the android guys. They seem to mandate an RTC
> > that can store time from 01/01/1970. I don't know much more than that
> > because they never cared to explain why that was actually necessary
> > (apart from a laconic "this will result in a bad user experience")
> >
> > I think tglx had a plan for offsetting the time at some point so 32-bit
> > platform can pass 2038 properly.
>
> Yes, but there are still quite some issues to solve there:
>
> 1) How do you tell the system that it should apply the offset in the
> first place, i.e at boot time before NTP or any other mechanism can
> correct it?
I'd not do offset. Instead, I'd select a threshold (perhaps year of
release of given kernel?) and
if (rtc_time < year_of_release_of_kernel)
rtc_time += 0x100000000;
Ok, we'll have to move away from "rtc_time == 0 indicates zero", as
seen in some drivers.
> 2) Deal with creative vendors who have their own idea about the 'start
> of the epoch'
If someone uses different threshold, well, there will be
confusion. But only for users that have their rtc set to the past,
which is quite unusual.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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next prev parent reply other threads:[~2017-06-21 7:51 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-20 21:35 [PATCH 00/51] rtc: stop using rtc deprecated functions Alexandre Belloni
[not found] ` <20170620213507.urobmtg34vzubrdq-m++hUPXGwpdeoWH0uzbU5w@public.gmane.org>
2017-06-20 22:00 ` Thomas Gleixner
2017-06-20 22:38 ` Russell King - ARM Linux
2017-06-21 7:51 ` Pavel Machek [this message]
2017-06-21 8:39 ` Alexandre Belloni
[not found] ` <20170621083907.y3gadsmsoufa5niv-m++hUPXGwpdeoWH0uzbU5w@public.gmane.org>
2017-06-21 6:34 ` Pavel Machek
2017-06-21 12:35 ` Alexandre Belloni
[not found] ` <20170621123535.b5fvwlydfhnhuqll-m++hUPXGwpdeoWH0uzbU5w@public.gmane.org>
2017-06-21 18:08 ` Pavel Machek
2017-06-21 9:19 ` Russell King - ARM Linux
[not found] ` <20170621091948.GP4902-l+eeeJia6m9URfEZ8mYm6t73F7V6hmMc@public.gmane.org>
2017-06-21 9:41 ` Alexandre Belloni
-- strict thread matches above, loose matches on Subject: below --
2017-06-20 9:35 Benjamin Gaignard
[not found] ` <1497951359-13334-1-git-send-email-benjamin.gaignard-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2017-06-20 10:03 ` Alexandre Belloni
[not found] ` <20170620100348.zh4ygvjjgnhxvmvl-m++hUPXGwpdeoWH0uzbU5w@public.gmane.org>
2017-06-20 10:07 ` Alexandre Belloni
2017-06-20 12:10 ` Pavel Machek
2017-06-20 12:24 ` Alexandre Belloni
[not found] ` <20170620122400.sm7qqvwyj6cuzarw-m++hUPXGwpdeoWH0uzbU5w@public.gmane.org>
2017-06-20 13:26 ` Pavel Machek
2017-06-20 13:37 ` Steve Twiss
[not found] ` <6ED8E3B22081A4459DAC7699F3695FB7018CD96FCD-68WUHU125fLzLL1Oxlh9IgLouzNaz+3S@public.gmane.org>
2017-06-20 13:44 ` Pavel Machek
2017-06-20 13:48 ` Alexandre Belloni
[not found] ` <20170620134827.ubvzhh25klaotupv-m++hUPXGwpdeoWH0uzbU5w@public.gmane.org>
2017-06-20 15:07 ` Benjamin Gaignard
[not found] ` <CA+M3ks68+z6nDtYM8CDpso7SxjB6Nt5E=rOc1yxx=kDz6PUeVQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-06-20 21:15 ` Russell King - ARM Linux
[not found] ` <20170620211536.GM4902-l+eeeJia6m9URfEZ8mYm6t73F7V6hmMc@public.gmane.org>
2017-06-21 9:26 ` David Laight
[not found] ` <063D6719AE5E284EB5DD2968C1650D6DD00278C0-VkEWCZq2GCInGFn1LkZF6NBPR1lH4CV8@public.gmane.org>
2017-06-21 9:35 ` Russell King - ARM Linux
2017-06-20 22:08 ` Pavel Machek
2017-06-21 9:14 ` Benjamin Gaignard
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