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cpufreq: Add CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING cpufreq driver flag

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The policy->transition_latency field is used for multiple purposes
today and its not straight forward at all. This is how it is used:

A. Set the correct transition_latency value.

B. Set it to CPUFREQ_ETERNAL because:
   1. We don't want automatic dynamic switching (with
      ondemand/conservative) to happen at all.
   2. We don't know the transition latency.

This patch handles the B.1. case in a more readable way. A new flag for
the cpufreq drivers is added to disallow use of cpufreq governors which
have dynamic_switching flag set.

All the current cpufreq drivers which are setting transition_latency
unconditionally to CPUFREQ_ETERNAL are updated to use it. They don't
need to set transition_latency anymore.

There shouldn't be any functional change after this patch.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Viresh Kumar
2017-07-19 15:42:48 +05:30
committed by Rafael J. Wysocki
parent 560c6e452d
commit fe829ed8ef
11 changed files with 26 additions and 18 deletions
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6
include/linux/cpufreq.h
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@@ -370,6 +370,12 @@ struct cpufreq_driver {
*/
#define CPUFREQ_NEED_INITIAL_FREQ_CHECK (1 << 5)
/*
* Set by drivers to disallow use of governors with "dynamic_switching" flag
* set.
*/
#define CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING (1 << 6)
int cpufreq_register_driver(struct cpufreq_driver *driver_data);
int cpufreq_unregister_driver(struct cpufreq_driver *driver_data);