APM or ACPI?------------If you have a relatively recent x86 mobile, desktop, or server system,odds are it supports either Advanced Power Management (APM) orAdvanced Configuration and Power Interface (ACPI). ACPI is the newerof the two technologies and puts power management in the hands of theoperating system, allowing for more intelligent power management thanis possible with BIOS controlled APM.The best way to determine which, if either, your system supports is tobuild a kernel with both ACPI and APM enabled (as of 2.3.x ACPI isenabled by default). If a working ACPI implementation is found, theACPI driver will override and disable APM, otherwise the APM driverwill be used.No, sorry, you cannot have both ACPI and APM enabled and running atonce. Some people with broken ACPI or broken APM implementationswould like to use both to get a full set of working features, but yousimply cannot mix and match the two. Only one power managementinterface 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 acpidrespectively, to be completely functional. Obtain both of thesedaemons 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 yoursystem the associated daemon will exit gracefully.