[PATCH] laptop-mode documentation update

The laptop mode docs don't say that no kernel configuration changes are
needed to use laptop mode.  That's caused some people to look for the
option.  This patch makes the doc explicitly mention the lack of an option.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/laptop-mode.txt

@@ -28,8 +28,9 @@ Contents
 The short story
 ---------------
 
-If you just want to use it, run the laptop_mode control script (which is included
-at the end of this document) as follows:
+To use laptop mode, you don't need to set any kernel configuration options
+or anything. You simply need to run the laptop_mode control script (which
+is included in this document) as follows:
 
 # laptop_mode start
 
@@ -78,12 +79,13 @@ Caveats
 The details
 -----------
 
-Laptop-mode is controlled by the flag /proc/sys/vm/laptop_mode. When this
-flag is set, any physical disk read operation (that might have caused the
-hard disk to spin up) causes Linux to flush all dirty blocks. The result
-of this is that after a disk has spun down, it will not be spun up anymore
-to write dirty blocks, because those blocks had already been written
-immediately after the most recent read operation
+Laptop-mode is controlled by the flag /proc/sys/vm/laptop_mode. This flag is
+present for all kernels that have the laptop mode patch, regardless of any
+configuration options. When the flag is set, any physical disk read operation
+(that might have caused the hard disk to spin up) causes Linux to flush all dirty
+blocks. The result of this is that after a disk has spun down, it will not be spun
+up anymore to write dirty blocks, because those blocks had already been written
+immediately after the most recent read operation.
 
 To increase the effectiveness of the laptop_mode strategy, the laptop_mode
 control script increases dirty_expire_centisecs and dirty_writeback_centisecs in