Re: [PATCH v1] ARM: clocksource: make ARM_GLOBAL_TIMER selectable

From	Russell King - ARM Linux <linux@arm.linux.org.uk>
Newsgroups	linux.kernel
Subject	Re: [PATCH v1] ARM: clocksource: make ARM_GLOBAL_TIMER selectable
Date	2016-04-27 12:50 +0200
Message-ID	<rsvcC-8ae-3@gated-at.bofh.it> (permalink)
References	<rsdfI-1Ck-13@gated-at.bofh.it> <rsdIK-27l-23@gated-at.bofh.it> <rsgZX-4OI-13@gated-at.bofh.it>
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On Tue, Apr 26, 2016 at 10:35:08PM +0300, Grygorii Strashko wrote:
> On 04/26/2016 07:02 PM, Liviu Dudau wrote:
> > Well, SoC-B has the GT *and* the DT node, so what is the problem with
> > enabling it for SoC-B? If there are reasons not to use the Global Timer
> > on SoC-B, surely a better option would be to mark it in DT with status = "disabled";
> 
> This was rejected [2]. DT describes HW and if it is functional the status = "disabled"
> is not good choice.
> ARM GT can't be used as clocksource/sched_clock/clockevent when CPUFreq or
> CPUIdle are enabled :(, and this is Linux specific functionality and
> not HW description. 

Sorry, but we don't want to have to disable drivers in the kernel just
because one platform has a problem (consider the single zImage case
where it may be required that the global timer is enabled for some
platform to boot - it becomes mandatory in single zImage at that point.)

Maybe a linux-specific property is needed here - "linux,low-power-unstable"
or something like that?

-- 
RMK's Patch system: http://www.arm.linux.org.uk/developer/patches/
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Thread

[PATCH v1] ARM: clocksource: make ARM_GLOBAL_TIMER selectable Grygorii Strashko <grygorii.strashko@ti.com> - 2016-04-26 17:40 +0200
  Re: [PATCH v1] ARM: clocksource: make ARM_GLOBAL_TIMER selectable Liviu Dudau <liviu.dudau@arm.com> - 2016-04-26 18:10 +0200
    Re: [PATCH v1] ARM: clocksource: make ARM_GLOBAL_TIMER selectable Grygorii Strashko <grygorii.strashko@ti.com> - 2016-04-26 21:40 +0200
      Re: [PATCH v1] ARM: clocksource: make ARM_GLOBAL_TIMER selectable Robin Murphy <robin.murphy@arm.com> - 2016-04-27 12:20 +0200
        Re: [PATCH v1] ARM: clocksource: make ARM_GLOBAL_TIMER selectable Grygorii Strashko <grygorii.strashko@ti.com> - 2016-04-27 15:30 +0200
      Re: [PATCH v1] ARM: clocksource: make ARM_GLOBAL_TIMER selectable Liviu Dudau <liviu.dudau@arm.com> - 2016-04-27 12:20 +0200
        Re: [PATCH v1] ARM: clocksource: make ARM_GLOBAL_TIMER selectable Grygorii Strashko <grygorii.strashko@ti.com> - 2016-04-27 15:50 +0200
      Re: [PATCH v1] ARM: clocksource: make ARM_GLOBAL_TIMER selectable Russell King - ARM Linux <linux@arm.linux.org.uk> - 2016-04-27 12:50 +0200
        Re: [PATCH v1] ARM: clocksource: make ARM_GLOBAL_TIMER selectable Grygorii Strashko <grygorii.strashko@ti.com> - 2016-04-27 15:40 +0200
          Re: [PATCH v1] ARM: clocksource: make ARM_GLOBAL_TIMER selectable Tony Lindgren <tony@atomide.com> - 2016-04-27 18:30 +0200
          Re: [PATCH v1] ARM: clocksource: make ARM_GLOBAL_TIMER selectable Russell King - ARM Linux <linux@arm.linux.org.uk> - 2016-04-27 23:10 +0200

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