Re: [PATCH v2 2/2] intel_pstate: Set core to min P state during core offline

From: Srivatsa S. Bhat
Date: Tue Mar 18 2014 - 14:53:24 EST

On 03/18/2014 08:31 PM, Dirk Brandewie wrote:
> On 03/17/2014 10:44 PM, Viresh Kumar wrote:
>> On Sat, Mar 15, 2014 at 2:33 AM, <dirk.brandewie@xxxxxxxxx> wrote:
>>> +
>>> static int intel_pstate_cpu_init(struct cpufreq_policy *policy)
>>> {
>>> struct cpudata *cpu;
>>> @@ -818,7 +824,7 @@ static struct cpufreq_driver intel_pstate_driver = {
>>> .setpolicy = intel_pstate_set_policy,
>>> .get = intel_pstate_get,
>>> .init = intel_pstate_cpu_init,
>>> - .exit = intel_pstate_cpu_exit,
>>> + .stop = intel_pstate_cpu_stop,
>> Probably, keep exit as is and only change P-state in stop(). So that
>> allocation of resources happen in init() and they are freed in exit()?
> I looked at doing just that but it junked up the code. if stop() is called
> during PREPARE then init() will be called via __cpufreq_add_dev() in the
> and DOWN_FAILED case. So once stop() is called the driver will be ready for
> init() to be called exactly like when exit() is called.

I'm sorry, but that didn't make much sense to me. Can you be a little
more specific as to what problems you hit while trying to have a
->stop() which sets min P state and a separate ->exit() which frees
the resources? I think we can achieve this with almost no trouble.

If you ignore the failure case (such as DOWN_FAILED) for now, do you
still see any serious roadblocks?

Srivatsa S. Bhat

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