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Diffstat (limited to 'Documentation/power/states.txt')
| -rw-r--r-- | Documentation/power/states.txt | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/Documentation/power/states.txt b/Documentation/power/states.txt index 0931a330d36..34800cc521b 100644 --- a/Documentation/power/states.txt +++ b/Documentation/power/states.txt @@ -62,17 +62,18 @@ setup via another operating system for it to use. Despite the inconvenience, this method requires minimal work by the kernel, since the firmware will also handle restoring memory contents on resume. -If the kernel is responsible for persistently saving state, a mechanism -called 'swsusp' (Swap Suspend) is used to write memory contents to -free swap space. swsusp has some restrictive requirements, but should -work in most cases. Some, albeit outdated, documentation can be found -in Documentation/power/swsusp.txt. +For suspend-to-disk, a mechanism called swsusp called 'swsusp' (Swap +Suspend) is used to write memory contents to free swap space. +swsusp has some restrictive requirements, but should work in most +cases. Some, albeit outdated, documentation can be found in +Documentation/power/swsusp.txt. Alternatively, userspace can do most +of the actual suspend to disk work, see userland-swsusp.txt. Once memory state is written to disk, the system may either enter a low-power state (like ACPI S4), or it may simply power down. Powering down offers greater savings, and allows this mechanism to work on any system. However, entering a real low-power state allows the user to -trigger wake up events (e.g. pressing a key or opening a laptop lid). +trigger wake up events (e.g. pressing a key or opening a laptop lid). A transition from Suspend-to-Disk to the On state should take about 30 seconds, though it's typically a bit more with the current |