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SubjectRe: [PATCH 1/2] cpufreq: Add stop callback to cpufreq_driver interface
On 03/19/2014 08:28 PM, Rafael J. Wysocki wrote:
> On Wednesday, March 19, 2014 11:31:31 PM Rafael J. Wysocki wrote:
>> On Wednesday, March 19, 2014 08:45:53 AM dirk.brandewie@gmail.com wrote:
>>> From: Dirk Brandewie <dirk.j.brandewie@intel.com>
>>>
>>> This callback allows the driver to do clean up before the CPU is
>>> completely down and its state cannot be modified. This is used
>>> by the intel_pstate driver to reduce the requested P state prior to
>>> the core going away. This is required because the requested P state
>>> of the offline core is used to select the package P state. This
>>> effectively sets the floor package P state to the requested P state on
>>> the offline core.
>>>
>>> Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
>
> To speed up things a bit I changed the name of the new callback to ->stop_cpu
> and made it void.
>
> I also modified patch [2/2] accordingly and queued the both of them up for 3.15.
>
> Please check the bleeding-edge branch.
>
> I wouldn't like to need to do anything like that any more in the future, though.

Sorry had appointments yesterday afternoon.

bleeding-edge looks good


>
>>> ---
>>> Documentation/cpu-freq/cpu-drivers.txt | 8 +++++++-
>>> drivers/cpufreq/cpufreq.c | 3 ++-
>>> include/linux/cpufreq.h | 1 +
>>> 3 files changed, 10 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/Documentation/cpu-freq/cpu-drivers.txt b/Documentation/cpu-freq/cpu-drivers.txt
>>> index 8b1a445..79def80 100644
>>> --- a/Documentation/cpu-freq/cpu-drivers.txt
>>> +++ b/Documentation/cpu-freq/cpu-drivers.txt
>>> @@ -61,7 +61,13 @@ target_index - See below on the differences.
>>>
>>> And optionally
>>>
>>> -cpufreq_driver.exit - A pointer to a per-CPU cleanup function.
>>> +cpufreq_driver.exit - A pointer to a per-CPU cleanup
>>> + function called during CPU_POST_DEAD
>>> + phase of cpu hotplug process.
>>> +
>>> +cpufreq_driver.stop - A pointer to a per-CPU stop function
>>> + called during CPU_DOWN_PREPARE phase of
>>> + cpu hotplug process.
>>>
>>> cpufreq_driver.resume - A pointer to a per-CPU resume function
>>> which is called with interrupts disabled
>>> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
>>> index cf485d9..bb20292 100644
>>> --- a/drivers/cpufreq/cpufreq.c
>>> +++ b/drivers/cpufreq/cpufreq.c
>>> @@ -1336,7 +1336,8 @@ static int __cpufreq_remove_dev_prepare(struct device *dev,
>>> __func__, new_cpu, cpu);
>>> }
>>> }
>>> - }
>>> + } else if (cpufreq_driver->stop && cpufreq_driver->setpolicy)
>>> + cpufreq_driver->stop(policy);
>>
>> Nit: Why is it an int function if the only caller doesn't check the
>> return value? It should be void.
>>
>>>
>>> return 0;
>>> }
>>> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
>>> index 4d89e0e..ff8db19 100644
>>> --- a/include/linux/cpufreq.h
>>> +++ b/include/linux/cpufreq.h
>>> @@ -224,6 +224,7 @@ struct cpufreq_driver {
>>> int (*bios_limit) (int cpu, unsigned int *limit);
>>>
>>> int (*exit) (struct cpufreq_policy *policy);
>>> + int (*stop) (struct cpufreq_policy *policy);
>>> int (*suspend) (struct cpufreq_policy *policy);
>>> int (*resume) (struct cpufreq_policy *policy);
>>> struct freq_attr **attr;
>>>
>>
>>
>



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