From 2df03ab3f34c13a7dbc69215add06ebe42985ffc Mon Sep 17 00:00:00 2001 From: Tom Rhodes Date: Thu, 12 Dec 2002 21:12:00 +0000 Subject: [PATCH] Bring in the ACPI documentation from my local tree. This is mostly complete, but still needs some work. --- .../books/handbook/config/chapter.sgml | 82 +++++++++++++++++++ 1 file changed, 82 insertions(+) diff --git a/en_US.ISO8859-1/books/handbook/config/chapter.sgml b/en_US.ISO8859-1/books/handbook/config/chapter.sgml index 93b36cab99..ebf736d972 100644 --- a/en_US.ISO8859-1/books/handbook/config/chapter.sgml +++ b/en_US.ISO8859-1/books/handbook/config/chapter.sgml @@ -1658,6 +1658,88 @@ kern.maxfiles: 2088 -> 5000 + + + + + + Hiten + Pandya + Written by + + + Tom + Rhodes + + + + + ACPI and FreeBSD + + It is very important to utilize hardware resources in an + efficient manner. Before ACPI was introduced, + it was very difficult and inflexible for operating systems to manage + the power usage and thermal properties of a system. The hardware was + either controlled by some sort of BIOS embedded + interface, i.e.: Plug and Play BIOS (PNPBIOS), + Advanced Power Management (APM) and so on. + Power and Resource Management is one of the key components of a modern + operating system. For example, you would want an operating system to + monitor system limits (and possibly take an action), in case your its + temperature increased unexpectedly. + + In this section of the FreeBSD Handbook, we will provide + comprehensive information about ACPI. References + will be provided for further reading, at the end. Please be aware + that ACPI is only availible on FreeBSD 5.X and + above. + + + What is ACPI? + + Advanced Configuration and Power Interface + (ACPI) is a standard written by + an alliance of vendors to provide a standard interface for + hardware resources and power management (hence the name). + It is a key element in Operating System-directed + configuration and Power Management, i.e.: it provides + more control and flexibility to the operating system (OS). + Modern systems stretched the limits of the current + Plug and Play interfaces (such as APM, which is used in FreeBSD 4.X), + prior to the introduction of ACPI. ACPI + is the direct successor to APM (Advanced Power + Management). + + + Configuring <acronym>ACPI</acronym> + + The acpi.ko driver is loaded by the + at start up by &man.loader.8; by default and should not + be compiled into the kernel. The reasoning behind this is that modules + are easier to work with, say if switching to another acpi.ko + without doing a kernel rebuild. This has the advantage of making testing easier. + Another reason is that starting ACPI after a system has been + brought up is not to useful, and in some cases can be fatal. If in doubt, just + disable ACPI all togeather. This driver should not and can not + be unloaded because the system bus uses it for various hardware interactions. + ACPI can be disabled with the &man.acpiconf.8; utility. + In fact most of the interaction with ACPI can be done via + &man.acpiconf.8;. Basicly this means, if anything about ACPI + is in the &man.dmesg.8; output, then most likely it is already running. + + ACPI and APM cannot coexist and + should be used sperately. The last one to load will terminate if the driver + notices the other running. + + In the simpleist form, ACPI can be used to put the + system into a sleep mode with &man.acpiconf.8;, the + flag, and a 1-5 option. Most users will only need + 1. Option 5 will do a soft-off + which is the same action as: + + &prompt.root;halt -p + +