On Monday 25 of November 2013 15:23:27 Guenter Roeck wrote: > On 11/25/2013 02:55 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 > > CPU_FREQ_S3C24XX 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 CPU_FREQ_S3C24XX 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@xxxxxxxxxxxx> > > --- > > drivers/watchdog/s3c2410_wdt.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c > > index 7d8fd04..4980f84 100644 > > --- a/drivers/watchdog/s3c2410_wdt.c > > +++ b/drivers/watchdog/s3c2410_wdt.c > > @@ -264,7 +264,7 @@ static irqreturn_t s3c2410wdt_irq(int irqno, void *param) > > return IRQ_HANDLED; > > } > > > > -#ifdef CONFIG_CPU_FREQ > > +#ifdef CONFIG_CPU_FREQ_S3C24XX > > > Where is the CPU_FREQ_S3C24XX configuration option defined ? I don't see it > in the current upstream kernel, so it appears that this depends on some > out-of-tree changes. Seems like it got renamed to ARM_S3C24XX_CPUFREQ by f023f8dd59. Best regards, Tomasz -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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