On Friday, March 14, 2014 02:03:56 PM dirk.brande...@gmail.com wrote:
> From: Dirk Brandewie <dirk.j.brande...@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.brande...@intel.com>
> ---
>  Documentation/cpu-freq/cpu-drivers.txt | 8 +++++++-
>  drivers/cpufreq/cpufreq.c              | 3 +++
>  include/linux/cpufreq.h                | 1 +
>  3 files changed, 11 insertions(+), 1 deletion(-)
> 
> 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..0d430d7 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1338,6 +1338,9 @@ static int __cpufreq_remove_dev_prepare(struct device 
> *dev,
>               }
>       }
>  
> +     if (cpufreq_driver->stop)

What about doing

+       if (cpufreq_driver->setpolicy && cpufreq_driver->stop)

here instead?  That would make it clear where the new callback belongs.

If you're fine with that, I can make that change when applying the patch.

> +             cpufreq_driver->stop(policy);
> +
>       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;
> 

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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