On Tue, 14 Aug 2007, Atsushi Nemoto wrote:
> Some difficulties are:
>
> * timekeeping subsystem calls {read,update}_persistent_clock() with
> irq-disabled. But most RTC class routines might sleep.
>
> * RTC class can have multiple RTCs on the system.
>
> * There are already some conflicting features in RTC class ---
> rtc_suspend and rtc_resume try to adjust the wall clock.
>
> * IIRC Some people said "NTP sync can be done all in userland" ;-)
NTP sync in the kernel disturbs the timer interrupt with some setups,
affecting the dispersion and thus the quality of timekeeping horribly.
Maciej
