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Re: [PATCH v2 1/3] cpufreq: add resolve_freq driver callback

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  Re: [PATCH v2 1/3] cpufreq: add resolve_freq driver callback Viresh Kumar <viresh.kumar@linaro.org> - 2016-05-31 13:20 +0200
    Re: [PATCH v2 1/3] cpufreq: add resolve_freq driver callback Steve Muckle <steve.muckle@linaro.org> - 2016-05-31 20:20 +0200

#1410161 — Re: [PATCH v2 1/3] cpufreq: add resolve_freq driver callback

On 25-05-16, 19:52, Steve Muckle wrote:
> +unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
> +					 unsigned int target_freq)
> +{
> +	struct cpufreq_frequency_table *freq_table;
> +	int index, retval;
> +
> +	clamp_val(target_freq, policy->min, policy->max);

Rafael will kill me for this, as I have fallen into the same trap and
copied your *incorrect* code :(

This is a useless statement unless you do:

target_freq = clamp_val(target_freq, policy->min, policy->max);

-- 
viresh

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#1410513

On Tue, May 31, 2016 at 04:44:51PM +0530, Viresh Kumar wrote:
> On 25-05-16, 19:52, Steve Muckle wrote:
> > +unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
> > +					 unsigned int target_freq)
> > +{
> > +	struct cpufreq_frequency_table *freq_table;
> > +	int index, retval;
> > +
> > +	clamp_val(target_freq, policy->min, policy->max);
> 
> Rafael will kill me for this, as I have fallen into the same trap and
> copied your *incorrect* code :(
> 
> This is a useless statement unless you do:
> 
> target_freq = clamp_val(target_freq, policy->min, policy->max);

Well I wouldn't worry too much, I copied it from Rafael's code in
cpufreq_driver_fast_switch() which also has this problem and needs to be
fixed.

Perhaps clamp_val could be changed to force the compiler to check that
its return value is being used.

thanks,
Steve

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