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Re: [PATCH] clocksource/arm_global_timer: reconfigure clockevents after cpufreq change

From Thomas Gleixner <tglx@linutronix.de>
Newsgroups linux.kernel
Subject Re: [PATCH] clocksource/arm_global_timer: reconfigure clockevents after cpufreq change
Date 2016-11-29 15:20 +0100
Message-ID <sIRqh-17H-3@gated-at.bofh.it> (permalink)
References <sIPy9-8o8-5@gated-at.bofh.it> <sIPy9-8o8-3@gated-at.bofh.it> <sIQXh-F4-67@gated-at.bofh.it> <sIRgC-12s-25@gated-at.bofh.it>
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On Tue, 29 Nov 2016, Alexander Kochetkov wrote:
> > 29 нояб. 2016 г., в 16:42, Thomas Gleixner <tglx@linutronix.de> написал(а):
> > 
> > The frequency change would not only affect the clockevent device, it also
> > would affect the clocksource. So the patch is incomplete, but see below.
> Looks like kernel disallow change clocksource and shed_clock rate at
> runtime. I haven’t found any function for that.
> 
> > 29 нояб. 2016 г., в 16:42, Thomas Gleixner <tglx@linutronix.de> написал(а):
> > 
> > That's broken and the clk framework should keep the CORE_PERI clock at a
> > constant rate by reprogramming the divider of the CPU clock.
> 
> Thank you for the hint.
> 
> > Assumptions w/o real impact are a perfect reason not to apply that
> > patch. This want's a proper proof that the global timer really changes and
> > this hackery is required, which I seriously doubt.
> 
> It really changes. It changes like it changes for smp-twd. I guess they are
> driven by same clock CORE_PERI.

If that happens then the whole thing wants to be disabled on those
misconfigured systems and not just hacked for nothing.

Thanks,

	tglx

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[PATCH] clocksource/arm_global_timer: reconfigure clockevents after cpufreq change Alexander Kochetkov <al.kochet@gmail.com> - 2016-11-29 13:20 +0100
  [PATCH] clocksource/arm_global_timer: reconfigure clockevents after cpufreq change Alexander Kochetkov <al.kochet@gmail.com> - 2016-11-29 13:20 +0100
    Re: [PATCH] clocksource/arm_global_timer: reconfigure clockevents  after cpufreq change Thomas Gleixner <tglx@linutronix.de> - 2016-11-29 14:50 +0100
      Re: [PATCH] clocksource/arm_global_timer: reconfigure clockevents after cpufreq change Alexander Kochetkov <al.kochet@gmail.com> - 2016-11-29 15:10 +0100
        Re: [PATCH] clocksource/arm_global_timer: reconfigure clockevents  after cpufreq change Thomas Gleixner <tglx@linutronix.de> - 2016-11-29 15:20 +0100
      Re: [PATCH] clocksource/arm_global_timer: reconfigure clockevents  after cpufreq change Marc Zyngier <marc.zyngier@arm.com> - 2016-11-29 15:20 +0100
        Re: [PATCH] clocksource/arm_global_timer: reconfigure clockevents  after cpufreq change Thomas Gleixner <tglx@linutronix.de> - 2016-11-29 15:40 +0100
          Re: [PATCH] clocksource/arm_global_timer: reconfigure clockevents after cpufreq change Alexander Kochetkov <al.kochet@gmail.com> - 2016-11-29 16:00 +0100
            Re: [PATCH] clocksource/arm_global_timer: reconfigure clockevents  after cpufreq change Robin Murphy <robin.murphy@arm.com> - 2016-11-29 16:10 +0100
          Re: [PATCH] clocksource/arm_global_timer: reconfigure clockevents  after cpufreq change Marc Zyngier <marc.zyngier@arm.com> - 2016-11-29 16:00 +0100
            Re: [PATCH] clocksource/arm_global_timer: reconfigure clockevents after cpufreq change Alexander Kochetkov <al.kochet@gmail.com> - 2016-11-29 16:10 +0100

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