-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 Some, albeit outdated, documentation can be found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 Some, albeit outdated, documentation can be found in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.