set_rtc_time() cleanup / normalization

[Richard Zidlicky]

> > On m68k, we removed that part because it confused NTP. Richard Zidlicky can
> > probably tell more about that.

more specific, syncinc systime with NTP could confuse hwclock,
see eg the thread following

http://marc.theaimsgroup.com/?l=linux-kernel&m=100448857801670&w=2

Although workarounds are possible, there are some more reasons
to dislike the hwclk update code in arch/*kernel/time.c:

- RTC should be accessed by proper rtc device driver only
- magic updates may confuse hwclock, adjtimex and other programs,
  some programs need to use workarounds to avoid triggering it.
- everything it does can be done much better by userspace
  accessing /dev/rtc
- implements policy and thus doesn´t belong into kernel
- getting rid of it saves a few clock cycles on every timer
  interrupt
- nobody can positively expect it to work, iirc many HW
  variants were never supported -> nothing can break if
  it is killed


Richard

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