On Monday 25 of November 2013 15:28:29 Doug Anderson wrote: > Guenter, > > On Mon, Nov 25, 2013 at 3:23 PM, Guenter Roeck <linux@xxxxxxxxxxxx> 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. > > Whoops! I guess I just trusted another patch and didn't dig. I was > basing this on https://patchwork.kernel.org/patch/3023421/ > > Ah, I see that Tomasz just found the answer. I'll update my patch. Seems like I originally gave you the wrong symbol name, looking at our internal 3.10 tree, where the rename is not present yet, and nobody noticed. Sorry for that. 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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