Messages in this thread | | | Date | Tue, 26 Nov 2013 10:14:54 -0800 | From | Guenter Roeck <> | Subject | Re: [PATCH v2] watchdog: s3c2410_wdt: Only register for cpufreq on ARM_S3C24XX_CPUFREQ |
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On 11/25/2013 03:36 PM, Doug Anderson wrote: > On modern SoCs the watchdog timer is parented on a clock that doesn't > change every time we have a cpufreq change. That means we don't need > to constantly adjust the watchdog timer, so avoid registering for and > dealing with cpufreq transitions unless we've actually got > CONFIG_ARM_S3C24XX_CPUFREQ defined. > > Note that this is more than just an optimization. The s3c2410 > watchdog driver actually pats the watchdog on every CPU frequency > change. On modern systems these happen many times per second (even in > a system where "nothing" is happening). That effectively makes any > userspace watchdog program useless (the watchdog is constantly patted > by the kernel). If we need ARM_S3C24XX_CPUFREQ defined on a > multiplatform kernel we'll need to make sure that kernel supports > common clock and change this to user common clock framework. > > Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
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