From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexandre Belloni Subject: Re: [PATCH 00/51] rtc: stop using rtc deprecated functions Date: Tue, 20 Jun 2017 15:48:27 +0200 Message-ID: <20170620134827.ubvzhh25klaotupv@piout.net> 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> <20170620134458.GA10104@amd> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Steve Twiss , Benjamin Gaignard , "linaro-kernel-cunTk1MwBs8s++Sfvej+rw@public.gmane.org" , "adi-buildroot-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org" , Alessandro Zummo , Gregory Clement , Ingo Molnar , Jason Cooper , John Stultz , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Linus Walleij , Michael Chan , "netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "rtc-linux-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org" Return-path: Content-Disposition: inline In-Reply-To: <20170620134458.GA10104@amd> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org On 20/06/2017 at 15:44:58 +0200, Pavel Machek wrote: > On Tue 2017-06-20 13:37:22, Steve Twiss wrote: > > Hi Pavel, > > > > On 20 June 2017 14:26, Pavel Machek wrote: > > > > > Subject: Re: [PATCH 00/51] rtc: stop using rtc deprecated functions > > > > > > 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 they > > > > > > > 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 not > > > > > > handle dates in y2038 anyway and as pointed by Russell a few month ago, > > > > > > rtc_time_to_tm will be able to catch it but the 64 bit version will > > > > > > 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. > > > > > > I wanted reference to Russell's mail. > > > > 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. > Yes, we agree on that but I won't cherry pick working patches from a 51 patches series. -- Alexandre Belloni, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com