diff options
| author | Zhang Rui <rui.zhang@intel.com> | 2013-05-13 06:42:11 +0400 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2013-05-14 03:41:37 +0400 |
| commit | dc5aeae4f961ca8ea9511422236d7076585f149a (patch) | |
| tree | 69e0efbccf0a2d3827ee7827905c23a9aa6ac0e1 /Documentation/power/states.txt | |
| parent | d5e1670afe0c886d6dd92afb7a1f085f88294dc8 (diff) | |
| download | linux-dc5aeae4f961ca8ea9511422236d7076585f149a.tar.xz | |
PM: Documentation update for freeze state
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'Documentation/power/states.txt')
| -rw-r--r-- | Documentation/power/states.txt | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/Documentation/power/states.txt b/Documentation/power/states.txt index 4416b28630df..42f28b7aaf6b 100644 --- a/Documentation/power/states.txt +++ b/Documentation/power/states.txt @@ -2,12 +2,26 @@ System Power Management States -The kernel supports three power management states generically, though -each is dependent on platform support code to implement the low-level -details for each state. This file describes each state, what they are +The kernel supports four power management states generically, though +one is generic and the other three are dependent on platform support +code to implement the low-level details for each state. +This file describes each state, what they are commonly called, what ACPI state they map to, and what string to write to /sys/power/state to enter that state +state: Freeze / Low-Power Idle +ACPI state: S0 +String: "freeze" + +This state is a generic, pure software, light-weight, low-power state. +It allows more energy to be saved relative to idle by freezing user +space and putting all I/O devices into low-power states (possibly +lower-power than available at run time), such that the processors can +spend more time in their idle states. +This state can be used for platforms without Standby/Suspend-to-RAM +support, or it can be used in addition to Suspend-to-RAM (memory sleep) +to provide reduced resume latency. + State: Standby / Power-On Suspend ACPI State: S1 |