Re: cpufreq_set_policy removed

[Thomas Renninger <trenn@suse.de>]

On Wed, 2007-06-20 at 15:20 -0600, Myron Stowe wrote:
> Thomas, Dave:
> 
> Do either of you have a problem with the existence of
> cpufreq_set_policy() or was it only removed because there were no
> remaining callers in the tree and it had bugs?
Both.

In cpufreq_set_policy:

	/* this one invokes verify and data->max could get lowered
           because of temperature or BIOS limitations
	*/
        ret = __cpufreq_set_policy(data, policy);
        data->user_policy.min = data->min;
        data->user_policy.max = data->max;
        /* here user_policy.max is getting overridden with a possible
	limited value. But it is used in update_policy to restore the
	unlimited values again */
        data->user_policy.policy = data->policy;
        data->user_policy.governor = data->governor;

I think in update_policy:
policy->cpuinfo.min_freq
policy->cpuinfo.max_freq
should get used anyway...

If really needed it could get exported again, but just use
cpu_get/cpu_put, set/unset a lock and invoke __cpufreq_set_policy in
between?

> 
> The reason why I ask is that I have been working on a module that
> changes cpufreq governors and I don't see any other way for a module to
> be able to change governors without this interface.
But governor changing is userspace job?
IMO this is not the best argument, why do you need switching governors
inside the kernel?

   Thomas