On 05/17/2013 09:25 PM, Srivatsa S. Bhat wrote:
> On 05/09/2013 02:35 AM, James Bottomley wrote:
>> On Wed, 2013-05-08 at 22:42 +0200, Helge Deller wrote:
>>> We need to enable local irqs to avoid this runtime warning.
>>>
>>> Signed-off-by: Helge Deller <deller@xxxxxx>
>>>
>>> diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
>>> index 55f92b6..2840d43 100644
>>> --- a/arch/parisc/kernel/process.c
>>> +++ b/arch/parisc/kernel/process.c
>>> @@ -286,3 +286,8 @@ void *dereference_function_descriptor(void *ptr)
>>> return ptr;
>>> }
>>> #endif
>>> +
>>> +void arch_cpu_idle(void)
>>> +{
>>> + local_irq_enable();
>>
>> This is definitely wrong. we'd need at least a cpu_relax() in there.
>> Without that the cpu will bounce around in the idle loop. I'd advise
>> that we simply keep the default cpu_idle_poll().
>>
>> However, this looks like a kernel bug to me in cpu_idle_loop()? not
>> something we should be working around in the arch code.
>>
>> Thomas, what's going on here? It looks like you can never avoid the
>> WARN_ON_ONCE if you don't provide any arch specific idle functions. If
>> you wish to allow this case then the correct patch (keeping the WARN_ON)
>> would appear to be this one.
>>
>> James
>>
>> ----
>> diff --git a/kernel/cpu/idle.c b/kernel/cpu/idle.c
>> index 8b86c0c..829e41f 100644
>> --- a/kernel/cpu/idle.c
>> +++ b/kernel/cpu/idle.c
>> @@ -56,6 +56,7 @@ void __weak arch_cpu_idle_dead(void) { }
>> void __weak arch_cpu_idle(void)
>> {
>> cpu_idle_force_poll = 1;
>> + local_irq_enable();
>> }
>>
>> /*
>>
>
> This patch looks like the correct fix to me.
>
> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
Thanks Srivatsa!
I can push it through the parisc tree if nobody objects...
Helge
--
To unsubscribe from this list: send the line "unsubscribe linux-parisc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
