Re: [PATCH 03/10] clocksource: Remove clocksource_max_deferment()

From: Richard Cochran
Date: Sun Jan 11 2015 - 06:47:35 EST



This series added:

+ /* Return 50% of the actual maximum, so we can detect bad values */
+ max_nsecs >>= 1;

and then...

On Fri, Jan 09, 2015 at 04:34:21PM -0800, John Stultz wrote:
> @@ -760,7 +746,8 @@ void __clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq)
> cs->maxadj = clocksource_max_adjustment(cs);
> }
>
> - cs->max_idle_ns = clocksource_max_deferment(cs);
> + cs->max_idle_ns = clocks_calc_max_nsecs(cs->mult, cs->shift,
> + cs->maxadj, cs->mask);
> }
> EXPORT_SYMBOL_GPL(__clocksource_updatefreq_scale);
>
> @@ -807,7 +794,8 @@ int clocksource_register(struct clocksource *cs)
> cs->name);
>
> /* calculate max idle time permitted for this clocksource */
> - cs->max_idle_ns = clocksource_max_deferment(cs);
> + cs->max_idle_ns = clocks_calc_max_nsecs(cs->mult, cs->shift,
> + cs->maxadj, cs->mask);

... the whole world's maximum idle time is artificially reduced by
half in order to catch some rare HW bug? Not a very green solution.

Thanks,
Richard
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