On 10/07/2015 08:18 AM, Prarit Bhargava wrote:
>
>
> On 10/06/2015 07:06 PM, Rafael J. Wysocki wrote:
>> On Wednesday, October 07, 2015 12:43:55 AM Rafael J. Wysocki wrote:
>>> On Tuesday, October 06, 2015 05:49:07 PM Prarit Bhargava wrote:
>
> <snip>
>
>>>>
>>>> diff --git a/drivers/cpufreq/intel_pstate.c
>>>> b/drivers/cpufreq/intel_pstate.c
>>>> index 3af9dd7..bb24458 100644
>>>> --- a/drivers/cpufreq/intel_pstate.c
>>>> +++ b/drivers/cpufreq/intel_pstate.c
>>>> @@ -986,6 +986,9 @@ static int intel_pstate_set_policy(struct
>>>> cpufreq_policy *policy)
>>>> if (!policy->cpuinfo.max_freq)
>>>> return -ENODEV;
>>>>
>>>> + limits.min_sysfs_pct = 0;
>>>> + limits.max_sysfs_pct = 100;
>>>> +
>>>> if (policy->policy == CPUFREQ_POLICY_PERFORMANCE &&
>>>> policy->max >= policy->cpuinfo.max_freq) {
>>>> limits.min_policy_pct = 100;
>>>> @@ -1004,9 +1007,9 @@ static int intel_pstate_set_policy(struct
>>>> cpufreq_policy *policy)
>>>> limits.max_policy_pct = clamp_t(int, limits.max_policy_pct, 0 , 100);
>>>>
>>>> /* Normalize user input to [min_policy_pct, max_policy_pct] */
>>>> - limits.min_perf_pct = max(limits.min_policy_pct, limits.min_sysfs_pct);
>>>> + limits.min_perf_pct = limits.min_policy_pct;
>>>> limits.min_perf_pct = min(limits.max_policy_pct, limits.min_perf_pct);
>>>> - limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct);
>>>> + limits.max_perf_pct = limits.max_sysfs_pct;
>>
>> On a second thought, isn't that always 100? If so, doesn't it basically
>> discard
>> limits.max_policy_pct?
>
> Wow :) I think you're right and that definitely was an unintended consequence
> of this patch. I also see that I can clean up the intel_pstate_set_policy()
> code a bit more. I'll submit a 2-part v2.
Kristen,
There is a question here and I'm going to need your input on the answer. The
question is whether or not a user can exceed the max_policy_pct or drop below
the min_policy_pct values via sysfs?
If "No, a user should not be able to exceed or go below those values", then IMO
limits.max_sysfs_pct should default to limits.max_policy_pct, and
limits.min_sysfs_pct should default to limits.min_policy_pct.
and I will adjust my patch accordingly.
P.
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