pm: remove obsolete piece of PM documentation

Remove some obsolete PM documentation.

The majority of contents of Documentation/power/pm.txt are
outdated.  Remove the outdated parts of this file and move the rest
to Documentation/power/apm-acpi.txt .  Update the index in
Documentation/power/ as appropriate.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/power/00-INDEX

@@ -1,5 +1,7 @@
 00-INDEX
 	- This file
+apm-acpi.txt
+	- basic info about the APM and ACPI support.
 basic-pm-debugging.txt
 	- Debugging suspend and resume
 devices.txt
@@ -14,8 +16,6 @@ notifiers.txt
 	- Registering suspend notifiers in device drivers
 pci.txt
 	- How the PCI Subsystem Does Power Management
-pm.txt
-	- info on Linux power management support.
 pm_qos_interface.txt
 	- info on Linux PM Quality of Service interface
 power_supply_class.txt

Documentation/power/apm-acpi.txt

@@ -0,0 +1,32 @@
+APM or ACPI?
+------------
+If you have a relatively recent x86 mobile, desktop, or server system,
+odds are it supports either Advanced Power Management (APM) or
+Advanced Configuration and Power Interface (ACPI).  ACPI is the newer
+of the two technologies and puts power management in the hands of the
+operating system, allowing for more intelligent power management than
+is possible with BIOS controlled APM.
+
+The best way to determine which, if either, your system supports is to
+build a kernel with both ACPI and APM enabled (as of 2.3.x ACPI is
+enabled by default).  If a working ACPI implementation is found, the
+ACPI driver will override and disable APM, otherwise the APM driver
+will be used.
+
+No, sorry, you cannot have both ACPI and APM enabled and running at
+once.  Some people with broken ACPI or broken APM implementations
+would like to use both to get a full set of working features, but you
+simply cannot mix and match the two.  Only one power management
+interface can be in control of the machine at once.  Think about it..
+
+User-space Daemons
+------------------
+Both APM and ACPI rely on user-space daemons, apmd and acpid
+respectively, to be completely functional.  Obtain both of these
+daemons from your Linux distribution or from the Internet (see below)
+and be sure that they are started sometime in the system boot process.
+Go ahead and start both.  If ACPI or APM is not available on your
+system the associated daemon will exit gracefully.
+
+  apmd:   http://worldvisions.ca/~apenwarr/apmd/
+  acpid:  http://acpid.sf.net/