1============
2APM or ACPI?
3============
4
5If you have a relatively recent x86 mobile, desktop, or server system,
6odds are it supports either Advanced Power Management (APM) or
7Advanced Configuration and Power Interface (ACPI).  ACPI is the newer
8of the two technologies and puts power management in the hands of the
9operating system, allowing for more intelligent power management than
10is possible with BIOS controlled APM.
11
12The best way to determine which, if either, your system supports is to
13build a kernel with both ACPI and APM enabled (as of 2.3.x ACPI is
14enabled by default).  If a working ACPI implementation is found, the
15ACPI driver will override and disable APM, otherwise the APM driver
16will be used.
17
18No, sorry, you cannot have both ACPI and APM enabled and running at
19once.  Some people with broken ACPI or broken APM implementations
20would like to use both to get a full set of working features, but you
21simply cannot mix and match the two.  Only one power management
22interface can be in control of the machine at once.  Think about it..
23
24User-space Daemons
25------------------
26Both APM and ACPI rely on user-space daemons, apmd and acpid
27respectively, to be completely functional.  Obtain both of these
28daemons from your Linux distribution or from the Internet (see below)
29and be sure that they are started sometime in the system boot process.
30Go ahead and start both.  If ACPI or APM is not available on your
31system the associated daemon will exit gracefully.
32
33  =====  =======================================
34  apmd   http://ftp.debian.org/pool/main/a/apmd/
35  acpid  http://acpid.sf.net/
36  =====  =======================================
37