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-rw-r--r--include/linux/cpufreq.h14
1 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 74f5cfff2b52..2b4f248b8ef1 100644
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -426,6 +426,20 @@ static inline unsigned long cpufreq_scale(unsigned long old, u_int div,
#define CPUFREQ_POLICY_POWERSAVE (1)
#define CPUFREQ_POLICY_PERFORMANCE (2)
+/*
+ * The polling frequency depends on the capability of the processor. Default
+ * polling frequency is 1000 times the transition latency of the processor. The
+ * ondemand governor will work on any processor with transition latency <= 10ms,
+ * using appropriate sampling rate.
+ *
+ * For CPUs with transition latency > 10ms (mostly drivers with CPUFREQ_ETERNAL)
+ * the ondemand governor will not work. All times here are in us (microseconds).
+ */
+#define MIN_SAMPLING_RATE_RATIO (2)
+#define LATENCY_MULTIPLIER (1000)
+#define MIN_LATENCY_MULTIPLIER (20)
+#define TRANSITION_LATENCY_LIMIT (10 * 1000 * 1000)
+
/* Governor Events */
#define CPUFREQ_GOV_START 1
#define CPUFREQ_GOV_STOP 2