Re: [PATCH] rtc: add rtc_systohc for ntp use

[Andrew Morton <akpm@linux-foundation.org>]

On Mon, 26 Jan 2009 17:04:22 -0800
Ed Swierk <eswierk@aristanetworks.com> wrote:

> Following up to Alessandro's RFC of 10 Nov 2008, this patch implements
> rtc_systohc() to update the configured rtc device (cmos, i2c, etc.) from
> the ntp-synchronized system clock.  It changes the ntp update code to
> call rtc_systohc() rather than update_persistent_clock() which (at least
> on x86) always updates the cmos rtc.
> 
> No attempt is made to compensate for the 500-ms delay imposed when
> setting a cmos rtc chip.  If you actually have a cmos rtc you can stick
> with the existing code, but at some point it would be nice to unify
> these.

I don't get this.  Do we not currently update the cmos clock in
response to NTP controls?  Does the patch now alter this policy, by now
updating the RTC?

IOW: what effect does this patch actually have upon the kernel?


Please cc Roman on NTP changes.  Roman, please consider sending in a
MAINTAINERS patch for this.


Please use scripts/checkpatch.pl.

Please fix the checkpatch warnings which this patch emits.

When fixing the extern-declaration-in-C warning, please consider
dropping the ifdefs around the rtc_systohc() declaration in the header
file.  They're not really needed.