Re: Not able to use HIGH_RES_TIMERS on ARM

From: Ajeet Yadav
Date: Fri Mar 23 2012 - 01:53:17 EST


CCing to stable@xxxxxxxxxxxxxxx
On Fri, Mar 23, 2012 at 8:58 AM, John Stultz <john.stultz@xxxxxxxxxx> wrote:
> On 03/22/2012 03:25 AM, Ajeet Yadav wrote:
>>
>> If I set ÂARCH_USES_GETTIMEOFFSET=n to use this feature, my target
>> fail to boot. (reason I well understand from our past discussions)
>
> And this point I'm not sure I'm following. Why exactly does disabling
> ARCH_USES_GETTIMEOFFSET cause boot failures? Could you expand on the details
> here?
We did some dissection to narrow down the patch, our latest kernel is
stable 3.0.X , however we backported patch " ARM: 7321/1: cache-v7:
Disable preemption when reading CCSIDR" from 3.0.25 stable tree, this
patch causes kernel hang during boot (IRQSOFF_TRACER=y and
PREEMPT_TRACER=y) with 100% probability , if we remove this patch or
disable the given CONFIG's then boot is success.
>
> You should just end up using the jiffies clocksource, which would give you
> low-res HZ granular timestamps, but shouldn't get in the way of booting.
>
> thanks
> -john
>
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