Messages in this thread | | | Date | Wed, 16 Mar 2016 17:58:18 +0100 | Subject | Re: [PATCH v4 6/7] cpufreq: Support for fast frequency switching | From | "Rafael J. Wysocki" <> |
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On Wed, Mar 16, 2016 at 4:43 PM, Peter Zijlstra <peterz@infradead.org> wrote: > On Wed, Mar 16, 2016 at 03:52:28PM +0100, Rafael J. Wysocki wrote: >> +void cpufreq_enable_fast_switch(struct cpufreq_policy *policy) >> +{ >> + mutex_lock(&cpufreq_fast_switch_lock); >> + if (policy->fast_switch_possible && cpufreq_fast_switch_count >= 0) { >> + cpufreq_fast_switch_count++; >> + policy->fast_switch_enabled = true; >> + } else { >> + pr_warn("cpufreq: CPU%u: Fast freqnency switching not enabled\n", >> + policy->cpu); > > This happens because there's transition notifiers, right? Would it make > sense to iterate the notifier here and print the notifier function > symbol for each? That way we've got a clue as to where to start looking > when this happens.
OK
>> + } >> + mutex_unlock(&cpufreq_fast_switch_lock); >> +} > >> @@ -1653,8 +1703,18 @@ int cpufreq_register_notifier(struct not >> >> switch (list) { >> case CPUFREQ_TRANSITION_NOTIFIER: >> + mutex_lock(&cpufreq_fast_switch_lock); >> + >> + if (cpufreq_fast_switch_count > 0) { >> + mutex_unlock(&cpufreq_fast_switch_lock); > > So while theoretically (it has a return code) > cpufreq_register_notifier() could fail, it never actually did. Now we > do. Do we want to add a WARN here?
Like if (WARN_ON(cpufreq_fast_switch_count > 0)) {
That can be done. :-)
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