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1.\"
2.\" Copyright (c) 2001 Michael Smith
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26.\" $FreeBSD: src/share/man/man4/acpi.4,v 1.50 2005/02/23 07:23:35 trhodes Exp $
494e572f 27.\" $DragonFly: src/share/man/man4/acpi.4,v 1.3 2005/07/03 20:58:35 asmodai Exp $
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28.\"
29.Dd February 13, 2005
30.Dt ACPI 4
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32.Sh NAME
33.Nm acpi
34.Nd Advanced Configuration and Power Management support
35.Sh SYNOPSIS
36.Cd "device acpi"
37.Pp
38.Cd "options ACPI_DEBUG"
39.Sh DESCRIPTION
40The
41.Nm
42driver provides support for the Intel/Microsoft/Compaq/Toshiba ACPI
43standard.
44This support includes platform hardware discovery (superseding the
45PnP and PCI BIOS), as well as power management (superseding APM) and
46other features.
47ACPI core support is provided by the ACPI CA reference implementation
48from Intel.
49.Pp
50Note that the
51.Nm
52driver is automatically loaded by the
53.Xr loader 8 ,
54and should only be
55compiled into the kernel on platforms where ACPI is mandatory.
56.Sh SYSCTLS
57The
58.Nm
59driver is intended to provide power management without user intervention.
60Thus, some of these sysctls are controlled automatically by the
61.Pa power_profile
62.Xr rc 8
63script, which can be configured via
64.Xr rc.conf 5 .
65If values are specified manually, they may be overridden.
66.Bl -tag -width indent
67.It Va hw.acpi.cpu.cx_usage
68Debugging information listing the percent of total usage for each sleep state.
69The values are reset when
70.Va hw.acpi.cpu.cx_lowest
71is modified.
72.It Va hw.acpi.cpu.cx_lowest
73Lowest Cx state to use for idling the CPU.
74A scheduling algorithm will select states between C1 and this setting
75as system load dictates.
76To enable ACPI CPU idling control,
77.Va machdep.cpu_idle_hlt
78must be set to 1.
79.It Va hw.acpi.cpu.cx_supported
80List of supported CPU idle states and their transition latency
81in microseconds.
82Each state has a type (e.g., C2).
83C1 is equivalent to the ia32 HLT instruction, C2 provides a deeper
84sleep with the same semantics, and C3 provides the deepest sleep
85but additionally requires bus mastering to be disabled.
86States greater than C3 provide even more power savings with the same
87semantics as the C3 state.
88Deeper sleeps provide more power savings but increased transition
89latency when an interrupt occurs.
90.El
91.Sh TUNABLES
92Tunables can be set at the
93.Xr loader 8
94prompt before booting the kernel or stored in
95.Pa /boot/loader.conf .
96.Bl -tag -width indent
97.It Va acpi_dsdt_load
98Enables loading of a custom ACPI DSDT.
99.It Va acpi_dsdt_name
100Name of the DSDT table to load, if loading is enabled.
101.It Va debug.acpi.disabled
102Selectively disables portions of ACPI for debugging purposes.
103.It Va debug.acpi.quirks
104Override any automatic quirks completely.
105.It Va hint.acpi.0.disabled
106Set this to 1 to disable all of ACPI.
107If ACPI has been disabled on your system due to a blacklist entry for your
108BIOS, you can set this to 0 to re-enable ACPI for testing.
109.It Va hw.acpi.ec.poll_timeout
110Delay in milliseconds to wait for the EC to respond.
111Try increasing this number if you get the error
112.Qq Li AE_NO_HARDWARE_RESPONSE .
113.It Va hw.acpi.host_mem_start
114Override the assumed memory starting address for PCI host bridges.
115.It Va hw.acpi.pci.link.%d.%d.%d.irq
116Override the interrupt to use.
117.It Va hw.acpi.reset_video
118Enables calling the VESA reset BIOS vector on the resume path.
119Some graphic chips have problems such as LCD white-out after resume.
120Try setting this to 0 if this causes problems for you.
121.It Va hw.acpi.serialize_methods
122Allow override of whether methods execute in parallel or not.
123Enable this for serial behavior, which fixes
124.Qq Li AE_ALREADY_EXISTS
125errors for
126AML that really cannot handle parallel method execution.
127It is off by default since this breaks recursive methods and some IBMs use
128such code.
129.It Va hw.acpi.verbose
130Turn on verbose debugging information about what ACPI is doing.
131.El
132.Sh DISABLING ACPI
133Since ACPI support on different platforms varies greatly, there are many
134debugging and tuning options available.
135.Pp
136For machines known not to work with
137.Nm
138enabled, there is a BIOS blacklist.
139Currently, the blacklist only controls whether
140.Nm
141should be disabled or not.
142In the future, it will have more granularity to control features (the
143infrastructure for that is already there).
144.Pp
145To enable
146.Nm
147(for debugging purposes, etc.) on machines that are on the blacklist, set the
148kernel environment variable
149.Va hint.acpi.0.disabled
150to 0.
151Before trying this, consider updating your BIOS to a more recent version that
152may be compatible with ACPI.
153.Pp
154To disable the
155.Nm
156driver completely, set the kernel environment variable
157.Va hint.acpi.0.disabled
158to 1.
159.Pp
160Some i386 machines totally fail to operate with some or all of ACPI disabled.
161Other i386 machines fail with ACPI enabled.
162Disabling all or part of ACPI on non-i386 platforms (i.e., platforms where
163ACPI support is mandatory) may result in a non-functional system.
164.Pp
165The
166.Nm
167driver comprises a set of drivers, which may be selectively disabled
168in case of problems.
169To disable a sub-driver, list it in the kernel
170environment variable
171.Va debug.acpi.disabled .
172Multiple entries can be listed, separated by a space.
173.Pp
174ACPI sub-devices and features that can be disabled:
175.Bl -tag -width ".Li sysresource"
176.It Li all
177Disable all ACPI features and devices.
178.It Li acad
179.Pq Vt device
180Supports AC adapter.
181.It Li bus
182.Pq Vt feature
183Probes and attaches subdevices.
184Disabling will avoid scanning the ACPI namespace entirely.
185.It Li children
186.Pq Vt feature
187Attaches standard ACPI sub-drivers and devices enumerated in the
188ACPI namespace.
189Disabling this has a similar effect to disabling
190.Dq Li bus ,
191except that the
192ACPI namespace will still be scanned.
193.It Li button
194.Pq Vt device
195Supports ACPI button devices (typically power and sleep buttons).
196.It Li cmbat
197.Pq Vt device
198Control-method batteries device.
199.It Li cpu
200.Pq Vt device
201Supports CPU power-saving and speed-setting functions.
202.It Li ec
203.Pq Vt device
204Supports the ACPI Embedded Controller interface, used to communicate
205with embedded platform controllers.
206.It Li isa
207.Pq Vt device
208Supports an ISA bus bridge defined in the ACPI namespace,
209typically as a child of a PCI bus.
210.It Li lid
211.Pq Vt device
212Supports an ACPI laptop lid switch, which typically puts a
213system to sleep.
214.It Li quirks
215.Pq Vt feature
216Do not honor quirks.
217Quirks automatically disable ACPI functionality based on the XSDT table's
218OEM vendor name and revision date.
219.It Li pci
220.Pq Vt device
221Supports Host to PCI bridges.
222.It Li pci_link
223.Pq Vt feature
224Performs PCI interrupt routing.
225.It Li sysresource
226.Pq Vt device
227Pseudo-devices containing resources which ACPI claims.
228.It Li thermal
229.Pq Vt device
230Supports system cooling and heat management.
231.It Li timer
232.Pq Vt device
233Implements a timecounter using the ACPI fixed-frequency timer.
234.It Li video
235.Pq Vt device
236Supports acpi_video which may conflict with agp device.
237.El
238.Pp
239It is also possible to avoid portions of the ACPI namespace which
240may be causing problems, by listing the full path of the root of
241the region to be avoided in the kernel environment variable
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242.Va debug.acpi.avoid.paths ,
243or
68fb0c66 244.Va debug.acpi.avoid .
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245The latter also disables initialization of ACPI namespace as a
246workaround for systems where not doing so crashes interpreter.
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247The object and all of its children will be ignored during the
248bus/children scan of the namespace.
249The ACPI CA code will still know about the avoided region.
250.Sh DEBUGGING OUTPUT
251To enable debugging output,
252.Nm
253must be compiled with
254.Cd "options ACPI_DEBUG" .
255Debugging output is separated between layers and levels, where a layer is
256a component of the ACPI subsystem, and a level is a particular kind
257of debugging output.
258.Pp
259Both layers and levels are specified as a whitespace-separated list of
260tokens, with layers listed in
261.Va debug.acpi.layer
262and levels in
263.Va debug.acpi.level .
264.Pp
265The first set of layers is for ACPI-CA components, and the second is for
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267drivers.
268The ACPI-CA layer descriptions include the prefix for the files they
269refer to.
270The supported layers are:
271.Pp
272.Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER"
273.It Li ACPI_UTILITIES
274Utility ("ut") functions
275.It Li ACPI_HARDWARE
276Hardware access ("hw")
277.It Li ACPI_EVENTS
278Event and GPE ("ev")
279.It Li ACPI_TABLES
280Table access ("tb")
281.It Li ACPI_NAMESPACE
282Namespace evaluation ("ns")
283.It Li ACPI_PARSER
284AML parser ("ps")
285.It Li ACPI_DISPATCHER
286Internal representation of interpreter state ("ds")
287.It Li ACPI_EXECUTER
288Execute AML methods ("ex")
289.It Li ACPI_RESOURCES
290Resource parsing ("rs")
291.It Li ACPI_CA_DEBUGGER
292Debugger implementation ("db", "dm")
293.It Li ACPI_OS_SERVICES
294Usermode support routines ("os")
295.It Li ACPI_CA_DISASSEMBLER
296Disassembler implementation (unused)
297.It Li ACPI_ALL_COMPONENTS
298All the above ACPI-CA components
299.It Li ACPI_AC_ADAPTER
300AC adapter driver
301.It Li ACPI_BATTERY
302Control-method battery driver
303.It Li ACPI_BUS
304ACPI, ISA, and PCI bus drivers
305.It Li ACPI_BUTTON
306Power and sleep button driver
307.It Li ACPI_EC
308Embedded controller driver
309.It Li ACPI_FAN
310Fan driver
311.It Li ACPI_OEM
312Platform-specific driver for hotkeys, LED, etc.
313.It Li ACPI_POWER
314Power resource driver
315.It Li ACPI_PROCESSOR
316CPU driver
317.It Li ACPI_THERMAL
318Thermal zone driver
319.It Li ACPI_TIMER
320Timer driver
321.It Li ACPI_ALL_DRIVERS
322All the above
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324ACPI drivers
325.El
326.Pp
327The supported levels are:
328.Pp
329.Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE"
330.It Li ACPI_LV_ERROR
331Fatal error conditions
332.It Li ACPI_LV_WARN
333Warnings and potential problems
334.It Li ACPI_LV_INIT
335Initialization progress
336.It Li ACPI_LV_DEBUG_OBJECT
337Stores to objects
338.It Li ACPI_LV_INFO
339General information and progress
340.It Li ACPI_LV_ALL_EXCEPTIONS
341All the previous levels
342.It Li ACPI_LV_INIT_NAMES
343.It Li ACPI_LV_PARSE
344.It Li ACPI_LV_LOAD
345.It Li ACPI_LV_DISPATCH
346.It Li ACPI_LV_EXEC
347.It Li ACPI_LV_NAMES
348.It Li ACPI_LV_OPREGION
349.It Li ACPI_LV_BFIELD
350.It Li ACPI_LV_TABLES
351.It Li ACPI_LV_VALUES
352.It Li ACPI_LV_OBJECTS
353.It Li ACPI_LV_RESOURCES
354.It Li ACPI_LV_USER_REQUESTS
355.It Li ACPI_LV_PACKAGE
356.It Li ACPI_LV_VERBOSITY1
357All the previous levels
358.It Li ACPI_LV_ALLOCATIONS
359.It Li ACPI_LV_FUNCTIONS
360.It Li ACPI_LV_OPTIMIZATIONS
361.It Li ACPI_LV_VERBOSITY2
362.It Li ACPI_LV_ALL
363.It Li ACPI_LV_MUTEX
364.It Li ACPI_LV_THREADS
365.It Li ACPI_LV_IO
366.It Li ACPI_LV_INTERRUPTS
367.It Li ACPI_LV_VERBOSITY3
368All the previous levels
369.It Li ACPI_LV_AML_DISASSEMBLE
370.It Li ACPI_LV_VERBOSE_INFO
371.It Li ACPI_LV_FULL_TABLES
372.It Li ACPI_LV_EVENTS
373.It Li ACPI_LV_VERBOSE
374All levels after
375.Qq Li ACPI_LV_VERBOSITY3
376.El
377.Pp
378Selection of the appropriate layer and level values is important
379to avoid massive amounts of debugging output.
380For example, the following configuration is a good way to gather initial
381information.
382It enables debug output for both ACPI-CA and the
383.Nm
384driver, printing basic information about errors, warnings, and progress.
385.Bd -literal -offset indent
386debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS"
387debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS"
388.Ed
389.Pp
390Debugging output by the ACPI CA subsystem is prefixed with the
391module name in lowercase, followed by a source line number.
392Output from the
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394code follows the same format, but
395the module name is uppercased.
396.Sh OVERRIDING YOUR BIOS BYTECODE
397ACPI interprets bytecode named AML
398(ACPI Machine Language)
399provided by the BIOS vendor as a memory image at boot time.
400Sometimes, the AML code contains a bug that does not appear when parsed
401by the Microsoft implementation.
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403provides a way to override it with your own AML code to work around
404or debug such problems.
405Note that all AML in your DSDT and any SSDT tables is overridden.
406.Pp
407In order to load your AML code, you must edit
408.Pa /boot/loader.conf
409and include the following lines.
410.Bd -literal -offset indent
411acpi_dsdt_load="YES"
412acpi_dsdt_name="/boot/acpi_dsdt.aml" # You may change this name.
413.Ed
414.Pp
415In order to prepare your AML code, you will need the
416.Xr acpidump 8
417and
418.Xr iasl 8
419utilities and some ACPI knowledge.
420.Sh COMPATIBILITY
421ACPI is only found and supported on i386/ia32, ia64, and amd64.
422.Sh SEE ALSO
423.Xr kenv 1 ,
424.Xr acpi_thermal 4 ,
425.Xr device.hints 5 ,
426.Xr loader.conf 5 ,
427.Xr acpiconf 8 ,
428.Xr acpidump 8 ,
429.Xr config 8 ,
430.Xr iasl 8
431.Rs
432.%A "Compaq Computer Corporation"
433.%A "Intel Corporation"
434.%A "Microsoft Corporation"
435.%A "Phoenix Technologies Ltd."
436.%A "Toshiba Corporation"
437.%D August 25, 2003
438.%T "Advanced Configuration and Power Interface Specification"
439.%O http://acpi.info/spec.htm
440.Re
441.Sh AUTHORS
442.An -nosplit
443The ACPI CA subsystem is developed and maintained by
444Intel Architecture Labs.
445.Pp
446The following people made notable contributions to the ACPI subsystem
447in
494e572f 448.Dx :
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449.An Michael Smith ,
450.An Takanori Watanabe Aq takawata@jp.FreeBSD.org ,
451.An Mitsuru IWASAKI Aq iwasaki@jp.FreeBSD.org ,
452.An Munehiro Matsuda ,
453.An Nate Lawson ,
454the ACPI-jp mailing list at
455.Aq acpi-jp@jp.FreeBSD.org ,
456and many other contributors.
457.Pp
458This manual page was written by
459.An Michael Smith Aq msmith@FreeBSD.org .
460.Sh BUGS
461If the
462.Nm
463driver is loaded as a module when it is already linked as part of the
464kernel, odd things may happen.