cpuidle: Allow idle states to be disabled by default

In certain situations it may be useful to prevent some idle states
from being used by default while allowing user space to enable them
later on.

For this purpose, introduce a new state flag, CPUIDLE_FLAG_OFF, to
mark idle states that should be disabled by default, make the core
set CPUIDLE_STATE_DISABLED_BY_USER for those states at the
initialization time and add a new state attribute in sysfs,
"default_status", to inform user space of the initial status of
the given idle state ("disabled" if CPUIDLE_FLAG_OFF is set for it,
"enabled" otherwise).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Rafael J. Wysocki
2019-12-13 09:56:13 +01:00
parent 18734958e9
commit 75a8026741
5 changed files with 25 additions and 1 deletions

View File

@@ -196,6 +196,12 @@ Description:
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/default_status
Date: December 2019
KernelVersion: v5.6
Contact: Linux power management list <linux-pm@vger.kernel.org>
Description:
(RO) The default status of this state, "enabled" or "disabled".
What: /sys/devices/system/cpu/cpuX/cpuidle/stateN/residency
Date: March 2014