X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=Documentation%2Fpower%2Finterface.txt;h=e67211fe0ee2f432044efe62e8909702f0b46fc9;hb=81f8320f624a785d77443ace83391d0fdee695f6;hp=a66bec222b16cba4caf24720da712c25a2372ed7;hpb=a12f66fccf2e266ad197df142b5ebafc6a169a8c;p=pandora-kernel.git diff --git a/Documentation/power/interface.txt b/Documentation/power/interface.txt index a66bec222b16..e67211fe0ee2 100644 --- a/Documentation/power/interface.txt +++ b/Documentation/power/interface.txt @@ -18,28 +18,34 @@ states. /sys/power/disk controls the operating mode of the suspend-to-disk -mechanism. Suspend-to-disk can be handled in several ways. The -greatest distinction is who writes memory to disk - the firmware or -the kernel. If the firmware does it, we assume that it also handles -suspending the system. - -If the kernel does it, then we have three options for putting the system -to sleep - using the platform driver (e.g. ACPI or other PM -registers), powering off the system or rebooting the system (for -testing). The system will support either 'firmware' or 'platform', and -that is known a priori. But, the user may choose 'shutdown' or -'reboot' as alternatives. - -Reading from this file will display what the mode is currently set -to. Writing to this file will accept one of - - 'firmware' - 'platform' +mechanism. Suspend-to-disk can be handled in several ways. We have a +few options for putting the system to sleep - using the platform driver +(e.g. ACPI or other suspend_ops), powering off the system or rebooting the +system (for testing). + +Additionally, /sys/power/disk can be used to turn on one of the two testing +modes of the suspend-to-disk mechanism: 'testproc' or 'test'. If the +suspend-to-disk mechanism is in the 'testproc' mode, writing 'disk' to +/sys/power/state will cause the kernel to disable nonboot CPUs and freeze +tasks, wait for 5 seconds, unfreeze tasks and enable nonboot CPUs. If it is +in the 'test' mode, writing 'disk' to /sys/power/state will cause the kernel +to disable nonboot CPUs and freeze tasks, shrink memory, suspend devices, wait +for 5 seconds, resume devices, unfreeze tasks and enable nonboot CPUs. Then, +we are able to look in the log messages and work out, for example, which code +is being slow and which device drivers are misbehaving. + +Reading from this file will display all supported modes and the currently +selected one in brackets, for example + + [shutdown] reboot test testproc + +Writing to this file will accept one of + + 'platform' (only if the platform supports it) 'shutdown' 'reboot' - -It will only change to 'firmware' or 'platform' if the system supports -it. + 'testproc' + 'test' /sys/power/image_size controls the size of the image created by the suspend-to-disk mechanism. It can be written a string