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Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
-rw-r--r--drivers/cpufreq/cpufreq.c34
1 files changed, 30 insertions, 4 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 0c728190e444..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 *
*********************************************************************/
@@ -1989,13 +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 {