Re: [PATCH 00/51] rtc: stop using rtc deprecated functions
From: Pavel Machek
Date: Wed Jun 21 2017 - 03:52:07 EST
> > 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.
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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