Re: RTC subsystem and fractions of seconds

[Hugh Dickins]

On Sat, 6 Jan 2007, David Brownell wrote:
> On Saturday 06 January 2007 3:26 pm, Philippe De Muyter wrote:
> 
> > The way it is done currently 
> > in drivers/rtc/hctosys.c is 0.5 sec off.  We could obtain a much better
> > precision by looping there until the next change (next second for old clocks,
> > next 0.01 second for m41t81, maybe even better for other ones).
> 
> Hmm ... "looping" fights against "quickly"; as would "wait for next
> update IRQ" (on RTCs that support that).  But it would improve precision,
> at least in the sense of having the system clock and that RTC spending
> less time with the lowest "seconds" digit disagreeing.
> 
> This is something you could write a patch for, n'est-ce pas?

If you're thinking of going that way, it'd be courteous to CC Matt,
who devoted some effort to removing just that loop in 2.6.17 ;)

Hugh
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