On Thursday, October 25, 2012 12:03:34 PM Viresh Kumar wrote:
> Hi Rafael,
>
> __cpufreq_driver_target() must not pass target frequency beyond the limits of
> current policy.
>
> Today most of cpufreq platform drivers are doing this check in their target
> routines. Why not move it to __cpufreq_driver_target().
>
> I wanted to get your opinion on this before making changes in all driver
> files.
> That's why this is an RFC.
I'd prefer to apply the patch below before changing the drviers.
Thanks,
Rafael
> Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org>
> ---
> drivers/cpufreq/cpufreq.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index f552d5f..59264f1 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -1470,12 +1470,19 @@ int __cpufreq_driver_target(struct cpufreq_policy
> *policy,
> unsigned int relation)
> {
> int retval = -EINVAL;
> + unsigned int old_target_freq = target_freq;
>
> if (cpufreq_disabled())
> return -ENODEV;
>
> - pr_debug("target for CPU %u: %u kHz, relation %u\n", policy->cpu,
> - target_freq, relation);
> + /* Make sure that target_freq is within supported range */
> + if (target_freq > policy->max)
> + target_freq = policy->max;
> + if (target_freq < policy->min)
> + target_freq = policy->min;
> +
> + pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
> + policy->cpu, target_freq, relation, old_target_freq);
> if (cpu_online(policy->cpu) && cpufreq_driver->target)
> retval = cpufreq_driver->target(policy, target_freq, relation);
>
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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