| 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/ |
