Documentation/ABI: update cpuidle sysfs documentation

Update cpuidle documentation using git logs and existing documentation
in Documentation/cpuidle/sysfs.txt. This might be useful for scripting
and tracking changes in the ABI.

Signed-off-by: Aishwarya Pant <aishpant@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
index bfd29bc..4ed63b6 100644 (file)
--- a/Documentation/ABI/testing/sysfs-devices-system-cpu
+++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
@@ -108,6 +108,8 @@ Description:        CPU topology files that describe a logical CPU's relationship
 
 What:          /sys/devices/system/cpu/cpuidle/current_driver
                /sys/devices/system/cpu/cpuidle/current_governer_ro
+               /sys/devices/system/cpu/cpuidle/available_governors
+               /sys/devices/system/cpu/cpuidle/current_governor
 Date:          September 2007
 Contact:       Linux kernel mailing list <linux-kernel@vger.kernel.org>
 Description:   Discover cpuidle policy and mechanism
@@ -119,13 +121,84 @@ Description:      Discover cpuidle policy and mechanism
                Idle policy (governor) is differentiated from idle mechanism
                (driver)
 
-               current_driver: displays current idle mechanism
+               current_driver: (RO) displays current idle mechanism
 
-               current_governor_ro: displays current idle policy
+               current_governor_ro: (RO) displays current idle policy
+
+               With the cpuidle_sysfs_switch boot option enabled (meant for
+               developer testing), the following three attributes are visible
+               instead:
+
+               current_driver: same as described above
+
+               available_governors: (RO) displays a space separated list of
+               available governors
+
+               current_governor: (RW) displays current idle policy. Users can
+               switch the governor at runtime by writing to this file.
 
                See files in Documentation/cpuidle/ for more information.
 
 
+What:          /sys/devices/system/cpu/cpuX/cpuidle/stateN/name
+               /sys/devices/system/cpu/cpuX/cpuidle/stateN/latency
+               /sys/devices/system/cpu/cpuX/cpuidle/stateN/power
+               /sys/devices/system/cpu/cpuX/cpuidle/stateN/time
+               /sys/devices/system/cpu/cpuX/cpuidle/stateN/usage
+Date:          September 2007
+KernelVersion: v2.6.24
+Contact:       Linux power management list <linux-pm@vger.kernel.org>
+Description:
+               The directory /sys/devices/system/cpu/cpuX/cpuidle contains per
+               logical CPU specific cpuidle information for each online cpu X.
+               The processor idle states which are available for use have the
+               following attributes:
+
+               name: (RO) Name of the idle state (string).
+
+               latency: (RO) The latency to exit out of this idle state (in
+               microseconds).
+
+               power: (RO) The power consumed while in this idle state (in
+               milliwatts).
+
+               time: (RO) The total time spent in this idle state (in microseconds).
+
+               usage: (RO) Number of times this state was entered (a count).
+
+
+What:          /sys/devices/system/cpu/cpuX/cpuidle/stateN/desc
+Date:          February 2008
+KernelVersion: v2.6.25
+Contact:       Linux power management list <linux-pm@vger.kernel.org>
+Description:
+               (RO) A small description about the idle state (string).
+
+
+What:          /sys/devices/system/cpu/cpuX/cpuidle/stateN/disable
+Date:          March 2012
+KernelVersion: v3.10
+Contact:       Linux power management list <linux-pm@vger.kernel.org>
+Description:
+               (RW) Option to disable this idle state (bool). The behavior and
+               the effect of the disable variable depends on the implementation
+               of a particular governor. In the ladder governor, for example,
+               it is not coherent, i.e. if one is disabling a light state, then
+               all deeper states are disabled as well, but the disable variable
+               does not reflect it. Likewise, if one enables a deep state but a
+               lighter state still is disabled, then this has no effect.
+
+
+What:          /sys/devices/system/cpu/cpuX/cpuidle/stateN/residency
+Date:          March 2014
+KernelVersion: v3.15
+Contact:       Linux power management list <linux-pm@vger.kernel.org>
+Description:
+               (RO) Display the target residency i.e. the minimum amount of
+               time (in microseconds) this cpu should spend in this idle state
+               to make the transition worth the effort.
+
+
 What:          /sys/devices/system/cpu/cpu#/cpufreq/*
 Date:          pre-git history
 Contact:       linux-pm@vger.kernel.org