powerpc + i2c/rtc : where is the 11 min update ?

Philippe De Muyter phdm at macqel.be
Wed May 21 00:07:44 EST 2008

CCing lkml

On Tue, May 20, 2008 at 09:10:25PM +1000, Paul Mackerras wrote:
> Philippe De Muyter writes:
> > I have a ARCH=powerpc linux-2.6.25-rc6 linux running with an i2c rtc chip,
> > and synchronized to a ntp server.
> > 
> > I noticed that my rtc chip does not get updated by the kernel, just like
> > it would be on all other architectures (included ppc).
> That is now supposed to be done by the code inside #ifdef
> CONFIG_GENERIC_CMOS_UPDATE in kernel/time/ntp.c.
> Paul.

Thanks.  I agree that is a good place.

But, here CONFIG_GENERIC_CMOS_UPDATE is defined and an i2c clock also,
and my rtc clock is not updated.  I see kernel/time/ntp.c::sync_cmos_clock
calling arch/powerpc/kernel/time.c::update_persistent_clock, where
ppc_md.set_rtc_time is NULL.

Who is supposed to initialize ppc_md.set_rtc_time to use an i2c clock and
when in the boot process may that happen ?

Or alternatively, should update_persistent_clock not be part of the rtc
subsystem ?


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