On 21/06/2017 at 09:51:52 +0200, Pavel Machek wrote: > 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. >
Or not, having an RTC set in the past is actually quite common. I'd find it weird to have a new device boot and be set to a date in the future. Also note that the threshold or offset thing may seem like a good idea but fails with many RTCs because of how they handle leap years. -- Alexandre Belloni, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -- You received this message because you are subscribed to "rtc-linux". Membership options at http://groups.google.com/group/rtc-linux . Please read http://groups.google.com/group/rtc-linux/web/checklist before submitting a driver. --- You received this message because you are subscribed to the Google Groups "rtc-linux" group. To unsubscribe from this group and stop receiving emails from it, send an email to rtc-linux+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
