40b4ac33b4
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 The majority of contents of Documentation/power/pm.txt are outdated. Remove the outdated parts of this file and move the rest to Documentation/power/apm-acpi.txt .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>
32 lines
1.5 KiB
Text
32 lines
1.5 KiB
Text
APM or ACPI?
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------------
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If you have a relatively recent x86 mobile, desktop, or server system,
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odds are it supports either Advanced Power Management (APM) or
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Advanced Configuration and Power Interface (ACPI). ACPI is the newer
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of the two technologies and puts power management in the hands of the
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operating system, allowing for more intelligent power management than
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is possible with BIOS controlled APM.
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The best way to determine which, if either, your system supports is to
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build a kernel with both ACPI and APM enabled (as of 2.3.x ACPI is
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enabled by default). If a working ACPI implementation is found, the
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ACPI driver will override and disable APM, otherwise the APM driver
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will be used.
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No, sorry, you cannot have both ACPI and APM enabled and running at
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once. Some people with broken ACPI or broken APM implementations
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would like to use both to get a full set of working features, but you
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simply cannot mix and match the two. Only one power management
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interface can be in control of the machine at once. Think about it..
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User-space Daemons
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------------------
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Both APM and ACPI rely on user-space daemons, apmd and acpid
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respectively, to be completely functional. Obtain both of these
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daemons from your Linux distribution or from the Internet (see below)
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and be sure that they are started sometime in the system boot process.
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Go ahead and start both. If ACPI or APM is not available on your
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system the associated daemon will exit gracefully.
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apmd: http://worldvisions.ca/~apenwarr/apmd/
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acpid: http://acpid.sf.net/
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