[PATCH 3/3] Documentation: intel_pstate: Add energy performance hint

[Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>]

Updated documentation for the support of energy performance hint.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 Documentation/cpu-freq/intel-pstate.txt | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/Documentation/cpu-freq/intel-pstate.txt b/Documentation/cpu-freq/intel-pstate.txt
index 198b2ef..e8c6fc8 100644
--- a/Documentation/cpu-freq/intel-pstate.txt
+++ b/Documentation/cpu-freq/intel-pstate.txt
@@ -139,6 +139,25 @@ architecture of the processor permits:
 - User can read write system wide turbo status
 	/sys/devices/system/cpu/no_turbo
 
+Support of energy performance hint
+It is possible to provide hints to the HWP algorithms in the processor
+to be more performance centric to more energy centric. When driver is
+using HWP, two additional cpufreq sysfs attributes are presented for
+each logical CPU.
+These attributes are:
+	- energy_performance_available_preferences
+	- energy_performance_preference
+
+To get list of supported hints:
+$ cat energy_performance_available_preferences
+    default performance balance_performance balance_power power
+
+The current preference can be read or changed via cpufreq sysfs
+attribute "energy_performance_preference". Reading from this attribute
+will display current effective setting. User can write any of the valid
+preference string to this attribute. User can always restore to power-on
+default by writing "default".
+
 Tuning Intel P-State driver
 
 When the performance can be tuned using PID (Proportional Integral
-- 
2.7.4