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Commit 209887e6 authored by Viresh Kumar's avatar Viresh Kumar Committed by Rafael J. Wysocki
Browse files

cpufreq: Return 0 from ->fast_switch() on errors 



CPUFREQ_ENTRY_INVALID is a special symbol which is used to specify that
an entry in the cpufreq table is invalid. But using it outside of the
scope of the cpufreq table looks a bit incorrect.

We can represent an invalid frequency by writing it as 0 instead if we
need. Note that it is already done that way for the return value of the
->get() callback.

Lets do the same for ->fast_switch() and not use CPUFREQ_ENTRY_INVALID
outside of the scope of cpufreq table.

Also update the comment over cpufreq_driver_fast_switch() to clearly
mention what this returns.

None of the drivers return CPUFREQ_ENTRY_INVALID as of now from
->fast_switch() callback and so we don't need to update any of those.

Signed-off-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent d6344d4b

drivers/cpufreq/cpufreq.c

+4 −3
Original line number Diff line number Diff line
@@ -1817,9 +1817,10 @@ EXPORT_SYMBOL(cpufreq_unregister_notifier); 
 * twice in parallel for the same policy and that it will never be called in

 * parallel with either ->target() or ->target_index() for the same policy.

 *

 * If CPUFREQ_ENTRY_INVALID is returned by the driver's ->fast_switch()

 * callback to indicate an error condition, the hardware configuration must be

 * preserved.

 * Returns the actual frequency set for the CPU.

 *

 * If 0 is returned by the driver's ->fast_switch() callback to indicate an

 * error condition, the hardware configuration must be preserved.

 */

unsigned int cpufreq_driver_fast_switch(struct cpufreq_policy *policy,

					unsigned int target_freq)

kernel/sched/cpufreq_schedutil.c

+1 −1
Original line number Diff line number Diff line
@@ -123,7 +123,7 @@ static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time, 


	if (policy->fast_switch_enabled) {

		next_freq = cpufreq_driver_fast_switch(policy, next_freq);

		if (next_freq == CPUFREQ_ENTRY_INVALID)

		if (!next_freq)

			return;



		policy->cur = next_freq;