/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.
+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
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 what the mode is currently set
-to. Writing to this file will accept one of
+Reading from this file will display all supported modes and the currently
+selected one in brackets, for example
- 'firmware'
- 'platform'
+ [shutdown] reboot test testproc
+
+Writing to this file will accept one of
+
+ 'platform' (only if the platform supports it)
'shutdown'
'reboot'
'testproc'
'test'
-It will only change to 'firmware' or 'platform' if the system supports
-it.
-
/sys/power/image_size controls the size of the image created by
the suspend-to-disk mechanism. It can be written a string
representing a non-negative integer that will be used as an upper