diff options
Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 41 |
1 files changed, 34 insertions, 7 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index 9bf97a366029..ea43b147a7fe 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -524,6 +524,32 @@ unsigned int cpufreq_driver_resolve_freq(struct cpufreq_policy *policy, } EXPORT_SYMBOL_GPL(cpufreq_driver_resolve_freq); +unsigned int cpufreq_policy_transition_delay_us(struct cpufreq_policy *policy) +{ + unsigned int latency; + + if (policy->transition_delay_us) + return policy->transition_delay_us; + + latency = policy->cpuinfo.transition_latency / NSEC_PER_USEC; + if (latency) { + /* + * For platforms that can change the frequency very fast (< 10 + * us), the above formula gives a decent transition delay. But + * for platforms where transition_latency is in milliseconds, it + * ends up giving unrealistic values. + * + * Cap the default transition delay to 10 ms, which seems to be + * a reasonable amount of time after which we should reevaluate + * the frequency. + */ + return min(latency * LATENCY_MULTIPLIER, (unsigned int)10000); + } + + return LATENCY_MULTIPLIER; +} +EXPORT_SYMBOL_GPL(cpufreq_policy_transition_delay_us); + /********************************************************************* * SYSFS INTERFACE * *********************************************************************/ @@ -1817,9 +1843,10 @@ 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) @@ -1988,13 +2015,13 @@ static int cpufreq_init_governor(struct cpufreq_policy *policy) if (!policy->governor) return -EINVAL; - if (policy->governor->max_transition_latency && - policy->cpuinfo.transition_latency > - policy->governor->max_transition_latency) { + /* Platform doesn't want dynamic frequency switching ? */ + if (policy->governor->dynamic_switching && + cpufreq_driver->flags & CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING) { struct cpufreq_governor *gov = cpufreq_fallback_governor(); if (gov) { - pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n", + pr_warn("Can't use %s governor as dynamic switching is disallowed. Fallback to %s governor\n", policy->governor->name, gov->name); policy->governor = gov; } else { |