CONFIG_ACPI Advanced Configuration and Power Interface (ACPI) support for Linux requires an ACPI compliant platform (hardware/firmware), and assumes the presence of OS-directed configuration and power management (OSPM) software. This option will enlarge your kernel by about 70K. Linux ACPI provides a robust functional replacement for several legacy configuration and power management intefaces, including the Plug-and-Play BIOS specification (PnP BIOS), the MultiProcessor Specification (MPS), and the Advanced Power Management (APM) specification. If both ACPI and APM support are configured, whichever is loaded first shall be used. Add "acpi=off" to the kernel command line to disable this feature. (Try "man bootparam" or see the documentation of your boot loader about how to pass options to the kernel at boot time.) ---------- The ACPI SourceForge project contains the latest source code, documentation, tools, mailing list subscription, and other information. This project is available at: <http://sourceforge.net/projects/acpi> Linux support for ACPI is based on Intel Corporation's ACPI Component Architecture (ACPI CA). For more information see: <http://developer.intel.com/technology/iapc/acpi> ACPI is an open industry specification co-developed by Compaq, Intel, Microsoft, Phoenix, and Toshiba. The specification is available at: <http://www.acpi.info> CONFIG_ACPI_HT_ONLY This option enables limited ACPI support -- just enough to enumerate processors from the ACPI Multiple APIC Description Table (MADT). Note that ACPI supports both logical (e.g. Hyper- Threading) and physical processors, where the MultiProcessor Specification (MPS) table only supports physical processors. Full ACPI support (CONFIG_ACPI) is preferred. Use this option only if you wish to limit ACPI's role to processor enumeration. There is no command-line option to disable this, but the kernel will fall back to the MPS table if the MADT is not present. CONFIG_ACPI_AC This driver adds support for the AC Adapter object, which indicates whether a system is on AC, or not. Typically, only mobile systems have this object, since desktops are always on AC. CONFIG_ACPI_BATTERY This driver adds support for battery information through /proc/acpi/battery. If you have a mobile system with a battery, say Y. CONFIG_ACPI_BUTTON This driver registers for events based on buttons, such as the power, sleep, and lid switch. In the future, a daemon will read /proc/acpi/event and perform user-defined actions such as shutting down the system. Until then, you can cat it, and see output when a button is pressed. CONFIG_ACPI_EC This driver is required on some systems for the proper operation of the battery and thermal drivers. If you are compiling for a mobile system, say Y. CONFIG_ACPI_PROCESSOR This driver installs ACPI as the idle handler for Linux, and uses ACPI C2 and C3 processor states to save power, on systems that support it. CONFIG_ACPI_THERMAL This driver adds support for ACPI thermal zones. Most mobile and some desktop systems support ACPI thermal zones. It is HIGHLY recommended that this option be enabled, as your processor(s) may be damaged without it. CONFIG_ACPI_FAN This driver adds support for ACPI fan devices, allowing user-mode applications to perform basic fan control (on, off, status). CONFIG_ACPI_SYSTEM This driver will enable your system to shut down using ACPI, and dump your ACPI DSDT table using /proc/acpi/dsdt. CONFIG_ACPI_DEBUG The ACPI driver can optionally report errors with a great deal of verbosity. Saying Y enables these statements. This will increase your kernel size by around 50K. CONFIG_ACPI_TOSHIBA This driver adds support for access to certain system settings on "legacy free" Toshiba laptops. These laptops can be recognized by their lack of a BIOS setup menu and APM support. On these machines, all system configuration is handled through the ACPI. This driver is required for access to controls not covered by the general ACPI drivers, such as LCD brightness, video output, etc. This driver differs from the non-ACPI Toshiba laptop driver (located under "Processor type and features") in several aspects. Configuration is accessed by reading and writing text files in the /proc tree instead of by program interface to /dev. Furthermore, no power management functions are exposed, as those are handled by the general ACPI drivers. More information about this driver is available at <http://memebeam.org/toys/ToshibaAcpiDriver>. If you have a legacy free Toshiba laptop (such as the Libretto L1 series), say Y.