linux-kernel - Re: [RFC v4 22/22] timekeeping: inform clockevents about freq adjustments

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Message-ID: <alpine.DEB.2.20.1608251654120.5714@nanos>
Date:   Thu, 25 Aug 2016 16:56:53 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Nicolai Stange <nicstange@...il.com>
cc:     John Stultz <john.stultz@...aro.org>, linux-kernel@...r.kernel.org
Subject: Re: [RFC v4 22/22] timekeeping: inform clockevents about freq
 adjustments

On Tue, 23 Aug 2016, Nicolai Stange wrote:
> Upon adjustments of the monotonic clock's frequencies from the
> timekeeping core, the clockevents devices' ->mult_adjusted should be
> changed accordingly, too.
> 
> Introduce clockevents_adjust_all_freqs() which traverses all registered
> clockevent devices and recalculates their ->mult_adjusted based on the
> monotonic clock's current frequency.

I'm not sure whether adjusting all devices is a good idea. We have systems
where the clockevent device is operated from a totally different crystal than
the clocksource device which is used for timekeeping. At least we want an
opt-out flag for this.
 
Thanks,

	tglx