Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752304AbdFTNpG (ORCPT ); Tue, 20 Jun 2017 09:45:06 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:34995 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751598AbdFTNpB (ORCPT ); Tue, 20 Jun 2017 09:45:01 -0400 Date: Tue, 20 Jun 2017 15:44:58 +0200 From: Pavel Machek To: Steve Twiss Cc: Alexandre Belloni , Benjamin Gaignard , "linaro-kernel@lists.linaro.org" , "adi-buildroot-devel@lists.sourceforge.net" , Alessandro Zummo , Gregory Clement , Ingo Molnar , Jason Cooper , John Stultz , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Linus Walleij , Michael Chan , "netdev@vger.kernel.org" , "rtc-linux@googlegroups.com" , Sebastian Hesselbarth , Support Opensource , Thomas Gleixner , "x86@kernel.org" , Baruch Siach , Hans Ulli Kroll , Vladimir Zapolskiy , Sylvain Lemieux , Barry Song , Maxime Ripard , Chen-Yu Tsai , Thierry Reding , Jonathan Hunter , "linux-tegra@vger.kernel.org" , "patches@opensource.wolfsonmicro.com" , "Rafael J. Wysocki" , Len Brown , "linux-pm@vger.kernel.org" Subject: Re: [PATCH 00/51] rtc: stop using rtc deprecated functions Message-ID: <20170620134458.GA10104@amd> References: <1497951359-13334-1-git-send-email-benjamin.gaignard@linaro.org> <20170620100348.zh4ygvjjgnhxvmvl@piout.net> <20170620121011.GA13221@amd> <20170620122400.sm7qqvwyj6cuzarw@piout.net> <20170620132620.GA16881@amd> <6ED8E3B22081A4459DAC7699F3695FB7018CD96FCD@SW-EX-MBX02.diasemi.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="bg08WKrSYDhXBjb5" Content-Disposition: inline In-Reply-To: <6ED8E3B22081A4459DAC7699F3695FB7018CD96FCD@SW-EX-MBX02.diasemi.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2259 Lines: 70 --bg08WKrSYDhXBjb5 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue 2017-06-20 13:37:22, Steve Twiss wrote: > Hi Pavel, >=20 > On 20 June 2017 14:26, Pavel Machek wrote: >=20 > > Subject: Re: [PATCH 00/51] rtc: stop using rtc deprecated functions > >=20 > > On Tue 2017-06-20 14:24:00, Alexandre Belloni wrote: > > > On 20/06/2017 at 14:10:11 +0200, Pavel Machek wrote: > > > > On Tue 2017-06-20 12:03:48, Alexandre Belloni wrote: > > > > > On 20/06/2017 at 11:35:08 +0200, Benjamin Gaignard wrote: > > > > > > rtc_time_to_tm() and rtc_tm_to_time() are deprecated because th= ey > > > > > > rely on 32bits variables and that will make rtc break in y2038/= 2016. > > > > > > > > > > Please don't, because this hide the fact that the hardware will n= ot > > > > > handle dates in y2038 anyway and as pointed by Russell a few mont= h ago, > > > > > rtc_time_to_tm will be able to catch it but the 64 bit version wi= ll > > > > > silently ignore it. > > > > > > > > Reference? Because rtc on PCs stores date in binary coded decimal, = so > > > > it is likely to break in 2100, not 2038... > > > > > > I'm not saying it should be done but clearly, that is not the correct > > > thing to do for RTCs that are using a single 32 bits register to store > > > the time. > > > You give one example, I can give you three: armada38x, at91sam9, > > > at32ap700x and that just in the beginning of the series. > >=20 > > I wanted reference to Russell's mail. >=20 > This is it. > https://patchwork.kernel.org/patch/6219401/ Thanks. Yes, that's argument against changing rtc _drivers_ for hardware that can not do better than 32bit. For generic code (such as 44/51 sysfs, 51/51 suspend test), the change still makes sense. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html --bg08WKrSYDhXBjb5 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAllJJtoACgkQMOfwapXb+vJ/zwCeK0sEIT2n0lCH87n4yUrGdTuK EuUAoLDZXsom6QhfNnq4JDr3oIaGFwye =dbxk -----END PGP SIGNATURE----- --bg08WKrSYDhXBjb5--