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ACPI(4)		       FreeBSD Kernel Interfaces Manual		       ACPI(4)

NAME
     acpi -- Advanced Configuration and	Power Management support

SYNOPSIS
     device acpi

     options ACPI_DEBUG

DESCRIPTION
     The acpi driver provides support for the Intel/Microsoft/Compaq/Toshiba
     ACPI standard.  This support includes platform hardware discovery (super-
     seding the	PnP and	PCI BIOS), as well as power management (superseding
     APM) and other features.  ACPI core support is provided by	the ACPI CA
     reference implementation from Intel.

     Note that the acpi	driver is automatically	loaded by the bootloader, and
     should not	normally be compiled into the kernel.

ENVIRONMENT
     This support is still experimental, and thus there	are many debugging and
     tuning options which are managed via the kernel environment space,	and
     set in the	loader(8) before booting the kernel.

     Debugging is separated between layers and levels, where a layer is	a por-
     tion of the ACPI subsystem, and a level is	a particular kind of debugging
     output.

     Both layers and levels are	specified as a whitespace-separated list of
     tokens, with layers listed	in debug.acpi.layer and	levels in
     debug.acpi.level.	The supported layers are:

	   ACPI_UTILITIES
	   ACPI_HARDWARE
	   ACPI_EVENTS
	   ACPI_TABLES
	   ACPI_NAMESPACE
	   ACPI_PARSER
	   ACPI_DISPATCHER
	   ACPI_EXECUTER
	   ACPI_RESOURCES
	   ACPI_CA_DEBUGGER
	   ACPI_OS_SERVICES
	   ACPI_CA_DISASSEMBLER
	   ACPI_ALL_COMPONENTS
	   ACPI_BUS
	   ACPI_SYSTEM
	   ACPI_POWER
	   ACPI_EC
	   ACPI_AC_ADAPTER
	   ACPI_BATTERY
	   ACPI_BUTTON
	   ACPI_PROCESSOR
	   ACPI_THERMAL
	   ACPI_FAN
	   ACPI_ALL_DRIVERS

     The supported levels are:

	   ACPI_LV_ERROR
	   ACPI_LV_WARN
	   ACPI_LV_INIT
	   ACPI_LV_DEBUG_OBJECT
	   ACPI_LV_INFO
	   ACPI_LV_ALL_EXCEPTIONS
	   ACPI_LV_INIT_NAMES
	   ACPI_LV_PARSE
	   ACPI_LV_LOAD
	   ACPI_LV_DISPATCH
	   ACPI_LV_EXEC
	   ACPI_LV_NAMES
	   ACPI_LV_OPREGION
	   ACPI_LV_BFIELD
	   ACPI_LV_TABLES
	   ACPI_LV_VALUES
	   ACPI_LV_OBJECTS
	   ACPI_LV_RESOURCES
	   ACPI_LV_USER_REQUESTS
	   ACPI_LV_PACKAGE
	   ACPI_LV_VERBOSITY1
	   ACPI_LV_ALLOCATIONS
	   ACPI_LV_FUNCTIONS
	   ACPI_LV_OPTIMIZATIONS
	   ACPI_LV_VERBOSITY2
	   ACPI_LV_ALL
	   ACPI_LV_MUTEX
	   ACPI_LV_THREADS
	   ACPI_LV_IO
	   ACPI_LV_INTERRUPTS
	   ACPI_LV_VERBOSITY3
	   ACPI_LV_AML_DISASSEMBLE
	   ACPI_LV_VERBOSE_INFO
	   ACPI_LV_FULL_TABLES
	   ACPI_LV_EVENTS
	   ACPI_LV_VERBOSE

     Selection of the appropriate layer	and level values is important to avoid
     massive amounts of	debugging output.  Check the code to see which you
     need.

     Debugging output by the ACPI CA subsystem is prefixed with	the module
     name in lowercase,	followed by a source line number.  Output from the
     FreeBSD-local code	follows	the same format, but the module	name is	upper-
     cased.

     To	disable	the acpi driver	completely, set	the kernel environment vari-
     able hint.acpi.0.disabled to 1.  Some i386	machines totally fail to oper-
     ate with some or all of ACPI disabled.  Other i386	machines fail with
     ACPI enabled.  Non-i386 platforms do not support operating	systems	which
     do	not use	ACPI.  Disabling all or	part of	ACPI on	non-i386 platforms may
     result in a non-functional	system.

     The acpi driver comprises a set of	drivers, which may be selectively dis-
     abled in case of problems.	 To disable a sub-driver, list it in the ker-
     nel environment variable debug.acpi.disable.

     ACPI sub-devices and features that	can be disabled:

     bus       (feature) Probes	and attaches subdevices.  Disabling will avoid
	       scanning	the ACPI namespace entirely.

     children  (feature) Attaches standard ACPI	sub-drivers and	devices	enu-
	       merated in the ACPI namespace.  Disabling this has a similar
	       effect to disabling ``bus'', except that	the ACPI namespace
	       will still be scanned.

     button    (device)	Supports ACPI button devices (typically	power and
	       sleep buttons).

     ec	       (device)	Supports the ACPI Embedded Controller interface, used
	       to communicate with embedded platform controllers.

     isa       (device)	Supports an ISA	bus bridge defined in the ACPI names-
	       pace, typically as a child of a PCI bus.

     lid       (device)	Supports an ACPI laptop	lid switch, which typically
	       puts a system to	sleep.

     pci       (device)	Supports Host to PCI bridges.

     cpu       (device)	Supports CPU power-saving and speed-setting functions.

     thermal   (device)	Supports system	cooling	and heat management.

     timer     (device)	Implements a timecounter using the ACPI	fixed-fre-
	       quency timer.

     It	is also	possible to avoid portions of the ACPI namespace which may be
     causing problems, by listing the full path	of the root of the region to
     be	avoided	in the kernel environment variable debug.acpi.avoid.  The
     object and	all of its children will be ignored during the bus/children
     scan of the namespace.  The ACPI CA code will still know about the
     avoided region.

OVERRIDING YOUR	BIOS BYTECODE
     ACPI interprets bytecode named AML, ACPI Machine Language,	provided by
     the BIOS vendor as	a memory image at boot time.  Sometimes, the AML code
     contains a	problem	that does not appear in	the Microsoft implementation.
     So	we provide a way to override it	with your own AML code.

     In	order to load your AML code, you must edit /boot/loader.conf and
     include the following lines.

	   acpi_dsdt_load="YES"
	   acpi_dsdt_name="/boot/acpi_dsdt.aml"	#You may change	the name.

     In	order to prepare your AML code,	you will need the acpidump(8) and
     iasl(1) utilities and some	ACPI knowledge.

TUNABLES
     acpi_dsdt_load
	     Enables loading of	a custom ACPI DSDT.

     acpi_dsdt_name
	     Name of the DSDT table to load, if	loading	is enabled.

     debug.acpi.disable
	     Selectively disables portions of ACPI for debugging purposes.

     hint.acpi.0.disabled
	     Disables all of ACPI.

     hw.acpi.ec.poll_timeout
	     Delay in milliseconds to wait for the EC to respond.  Try
	     increasing	this number if you get the error
	     AE_NO_HARDWARE_RESPONSE.

     hw.acpi.reset_video
	     Enables calling the VESA reset BIOS vector	on the resume path.
	     Some graphic chips	have problems such as LCD white-out after
	     resume.  Try setting this to 0 if this causes problems for	you.

     hw.acpi.os_name
	     Some systems' ASL may have	problems because they look for names
	     of	Microsoft operating systems.  This tunable overrides the
	     default value of "FreeBSD".

     hw.acpi.pci.link.%d.%d.%d.irq
	     Override the interrupt to use.

     hw.acpi.verbose
	     Turn on verbose debugging information about what ACPI is doing.

SYSCTLS
     hw.acpi.cpu.performance_speed
	     Sets the speed of the CPU,	if it supports multiple	speeds,	while
	     in	the performance	power profile.

     hw.acpi.cpu.economy_speed
	     Sets the speed of the CPU,	if it supports multiple	speeds,	while
	     in	the economy power profile.

     hw.acpi.cpu.cx_history
	     Debugging information listing all sleep states and	the number of
	     long and short sleeps for each one.  The counters are reset when
	     hw.acpi.cpu.cx_lowest is modified.

     hw.acpi.cpu.cx_lowest
	     Zero-based	index of the lowest CPU	idle state to use.  A schedul-
	     ing algorithm will	select between 0...index for the state to use
	     during the	next sleep.  To	enable ACPI CPU	idling control,
	     machdep.cpu_idle_hlt must be set to 1.

     hw.acpi.cpu.cx_supported
	     List of supported CPU idle	states and their transition latency in
	     microseconds.  Each state has a type, C1-3.  C1 is	equivalent to
	     the ia32 HLT instruction, C2 provides a deeper sleep with the
	     same semantics, and C3 provides the deepest sleep but addition-
	     ally requires bus mastering to be disabled.  Deeper sleeps	pro-
	     vide more power savings but increased transition latency when an
	     interrupt occurs.

COMPATIBILITY
     ACPI is only found	and supported on i386/ia32, ia64, and amd64.

SEE ALSO
     loader.conf(5), acpiconf(8), acpidump(8), config(8), iasl(8)

     Compaq Computer Corporation, Intel	Corporation, Microsoft Corporation,
     Phoenix Technologies Ltd.,	and Toshiba Corporation, Advanced
     Configuration and Power Interface Specification, August 25, 2003,
     http://acpi.info/spec.htm.

AUTHORS
     The ACPI CA subsystem is developed	and maintained by Intel	Architecture
     Labs.

     The following people made notable contributions to	the ACPI subsystem in
     FreeBSD: Michael Smith, Takanori Watanabe <takawata@jp.FreeBSD.org>,
     Mitsuru IWASAKI <iwasaki@jp.FreeBSD.org>, Munehiro	Matsuda, Nate Lawson,
     the ACPI-jp mailing list at <acpi-jp@jp.FreeBSD.org>, and many other con-
     tributors.

     This manual page was written by Michael Smith <msmith@FreeBSD.org>.

BUGS
     If	the acpi driver	is loaded as a module when it is already linked	as
     part of the kernel, odd things may	happen.

FreeBSD	10.1			 July 2, 2001			  FreeBSD 10.1

NAME | SYNOPSIS | DESCRIPTION | ENVIRONMENT | OVERRIDING YOUR BIOS BYTECODE | TUNABLES | SYSCTLS | COMPATIBILITY | SEE ALSO | AUTHORS | BUGS

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