Re: [PATCH] ARM: Drop fixed 200 Hz timer requirement from Exynos platforms

From	Krzysztof Kozlowski <krzk@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] ARM: Drop fixed 200 Hz timer requirement from Exynos platforms
Date	2016-11-18 07:50 +0100
Message-ID	<sEL9L-3yY-1@gated-at.bofh.it> (permalink)
References	<sDub0-28T-25@gated-at.bofh.it> <sEw14-1T0-25@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Thu, Nov 17, 2016 at 01:35:45PM +0100, Arnd Bergmann wrote:
> On Monday, November 14, 2016 8:27:05 PM CET Krzysztof Kozlowski wrote:
> > @@ -1497,7 +1497,7 @@ source kernel/Kconfig.preempt
> >  config HZ_FIXED
> >         int
> >         default 200 if ARCH_EBSA110 || ARCH_S3C24XX || \
> > -               ARCH_S5PV210 || ARCH_EXYNOS4
> > +               ARCH_S5PV210
> >         default 128 if SOC_AT91RM9200
> >         default 0
> 
> After further research, I've concluded that we should also drop the
> settings for ARCH_S5PV210 and ARCH_S3C24XX here.
> 
> ARCH_S5PV210 behaves exactly like EXYNOS here, it has 32-bit timers
> so there won't be any overflow with 100Hz.
> 
> For ARCH_S3C24XX, it the requirement was that HZ_100 could not
> be used with the old arch/arm/plat-samsung/time.c code that would
> overflow its 16-bit counter.
> However, the new drivers/clocksource/samsung_pwm_timer.c configures
> the clock divider to '50' instead of '6', so there is no longer
> a 16-bit overflow before the 100Hz tick, it now overflows every
> 3.7ms for the typical 12MHz clock.

I can send an updated version however testing would be nice... I know
Sylwester has a S3C6410 platform running, maybe S3C24xx as well.

Best regards,
Krzysztof

Thread

[PATCH] ARM: Drop fixed 200 Hz timer requirement from Exynos platforms Krzysztof Kozlowski <krzk@kernel.org> - 2016-11-14 19:30 +0100
  Re: [PATCH] ARM: Drop fixed 200 Hz timer requirement from Exynos platforms Arnd Bergmann <arnd@arndb.de> - 2016-11-17 15:40 +0100
    Re: [PATCH] ARM: Drop fixed 200 Hz timer requirement from Exynos  platforms Krzysztof Kozlowski <krzk@kernel.org> - 2016-11-18 07:50 +0100
  Re: [PATCH] ARM: Drop fixed 200 Hz timer requirement from Exynos  platforms Javier Martinez Canillas <javier@osg.samsung.com> - 2016-11-17 18:40 +0100

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