linux-kernel - Re: [PATCH v3 1/3] cpufreq: add cpufreq_driver_resolve

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Message-ID: <20160721211344.GJ3122@ubuntu>
Date:	Thu, 21 Jul 2016 14:13:44 -0700
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	Steve Muckle <steve.muckle@...aro.org>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	"Rafael J . Wysocki" <rjw@...ysocki.net>,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Morten Rasmussen <morten.rasmussen@....com>,
	Dietmar Eggemann <dietmar.eggemann@....com>,
	Juri Lelli <Juri.Lelli@....com>,
	Patrick Bellasi <patrick.bellasi@....com>,
	Steve Muckle <smuckle@...aro.org>
Subject: Re: [PATCH v3 1/3] cpufreq: add cpufreq_driver_resolve_freq()

On 13-07-16, 13:25, Steve Muckle wrote:
> +unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy,
> +					 unsigned int target_freq)
> +{
> +	target_freq = clamp_val(target_freq, policy->min, policy->max);
> +	policy->cached_target_freq = target_freq;
> +	if (cpufreq_driver->resolve_freq)
> +		return cpufreq_driver->resolve_freq(policy, target_freq);
> +	policy->cached_resolved_idx =
> +		cpufreq_frequency_table_target(policy, target_freq,
> +					       CPUFREQ_RELATION_L);
> +	return policy->freq_table[policy->cached_resolved_idx].frequency;

FWIW, this may crash the kernel for a driver that provides ->target()
but no ->resolve_freq().

-- 
viresh