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 $
27 .\" $DragonFly: src/share/man/man4/acpi.4,v 1.8 2008/08/28 16:38:59 swildner Exp $
29 .Dd September 29, 2007
34 .Nd Advanced Configuration and Power Management support
38 .Cd "options ACPI_DEBUG"
42 driver provides support for the Intel/Microsoft/Compaq/Toshiba ACPI
44 This support includes platform hardware discovery (superseding the
45 PnP and PCI BIOS), as well as power management (superseding APM) and
47 ACPI core support is provided by the ACPI CA reference implementation
52 driver is automatically loaded by the
55 compiled into the kernel on platforms where ACPI is mandatory.
59 driver is intended to provide power management without user intervention.
60 Thus, some of these sysctls are controlled automatically by the
63 script, which can be configured via
65 If values are specified manually, they may be overridden.
66 .Bl -tag -width indent
67 .It Va hw.acpi.cpu.cx_usage
68 Debugging information listing the percent of total usage for each sleep state.
69 The values are reset when
70 .Va hw.acpi.cpu.cx_lowest
72 .It Va hw.acpi.cpu.cx_lowest
73 Lowest Cx state to use for idling the CPU.
74 A scheduling algorithm will select states between C1 and this setting
75 as system load dictates.
76 To enable ACPI CPU idling control,
77 .Va machdep.cpu_idle_hlt
79 .It Va hw.acpi.cpu.cx_supported
80 List of supported CPU idle states and their transition latency
82 Each state has a type (e.g., C2).
83 C1 is equivalent to the ia32 HLT instruction, C2 provides a deeper
84 sleep with the same semantics, and C3 provides the deepest sleep
85 but additionally requires bus mastering to be disabled.
86 States greater than C3 provide even more power savings with the same
87 semantics as the C3 state.
88 Deeper sleeps provide more power savings but increased transition
89 latency when an interrupt occurs.
92 Tunables can be set at the
94 prompt before booting the kernel or stored in
95 .Pa /boot/loader.conf .
96 .Bl -tag -width indent
98 Enables loading of a custom ACPI DSDT.
100 Name of the DSDT table to load, if loading is enabled.
101 .It Va debug.acpi.disabled
102 Selectively disables portions of ACPI that are enabled by default, for
104 .It Va debug.acpi.enabled
105 Selectively enables portions of ACPI that are disabled by default, for
107 .It Va debug.acpi.quirks
108 Override any automatic quirks completely.
109 .It Va hint.acpi.0.disabled
110 Set this to 1 to disable all of ACPI.
111 If ACPI has been disabled on your system due to a blacklist entry for your
112 BIOS, you can set this to 0 to re-enable ACPI for testing.
113 .It Va hw.acpi.ec.poll_timeout
114 Delay in milliseconds to wait for the EC to respond.
115 Try increasing this number if you get the error
116 .Qq Li AE_NO_HARDWARE_RESPONSE .
117 .It Va hw.acpi.host_mem_start
118 Override the assumed memory starting address for PCI host bridges.
119 .It Va hw.acpi.pci.link.%d.%d.%d.irq
120 Override the interrupt to use.
121 .It Va hw.acpi.reset_video
122 Enables calling the VESA reset BIOS vector on the resume path.
123 Some graphic chips have problems such as LCD white-out after resume.
124 Try setting this to 0 if this causes problems for you.
125 .It Va hw.acpi.serialize_methods
126 Allow override of whether methods execute in parallel or not.
127 Enable this for serial behavior, which fixes
128 .Qq Li AE_ALREADY_EXISTS
130 AML that really cannot handle parallel method execution.
131 It is off by default since this breaks recursive methods and some IBMs use
133 .It Va hw.acpi.verbose
134 Turn on verbose debugging information about what ACPI is doing.
137 Since ACPI support on different platforms varies greatly, there are many
138 debugging and tuning options available.
140 For machines known not to work with
142 enabled, there is a BIOS blacklist.
143 Currently, the blacklist only controls whether
145 should be disabled or not.
146 In the future, it will have more granularity to control features (the
147 infrastructure for that is already there).
151 (for debugging purposes, etc.) on machines that are on the blacklist, set the
152 kernel environment variable
153 .Va hint.acpi.0.disabled
155 Before trying this, consider updating your BIOS to a more recent version that
156 may be compatible with ACPI.
160 driver completely, set the kernel environment variable
161 .Va hint.acpi.0.disabled
164 Some i386 machines totally fail to operate with some or all of ACPI disabled.
165 Other i386 machines fail with ACPI enabled.
166 Disabling all or part of ACPI on non-i386 platforms (i.e., platforms where
167 ACPI support is mandatory) may result in a non-functional system.
171 driver comprises a set of drivers, which may be selectively disabled
173 To disable a sub-driver, list it in the kernel
175 .Va debug.acpi.disabled .
176 Multiple entries can be listed, separated by a space.
178 ACPI sub-devices and features that can be disabled:
179 .Bl -tag -width ".Li sysresource"
181 Disable all ACPI features and devices.
187 Probes and attaches subdevices.
188 Disabling will avoid scanning the ACPI namespace entirely.
191 Attaches standard ACPI sub-drivers and devices enumerated in the
193 Disabling this has a similar effect to disabling
196 ACPI namespace will still be scanned.
199 Supports ACPI button devices (typically power and sleep buttons).
202 Control-method batteries device.
205 Supports CPU power-saving and speed-setting functions.
208 Supports CPU power-saving.
211 will also disable this device.
214 Supports CPU speed-setting.
217 will also disable this device.
220 Supports the ACPI Embedded Controller interface, used to communicate
221 with embedded platform controllers.
224 Supports an ISA bus bridge defined in the ACPI namespace,
225 typically as a child of a PCI bus.
228 Supports an ACPI laptop lid switch, which typically puts a
233 Quirks automatically disable ACPI functionality based on the XSDT table's
234 OEM vendor name and revision date.
237 Supports Host to PCI bridges.
240 Performs PCI interrupt routing.
243 Pseudo-devices containing resources which ACPI claims.
246 Supports system cooling and heat management.
249 Implements a timecounter using the ACPI fixed-frequency timer.
252 Supports acpi_video which may conflict with agp device.
257 driver comprises a set of drivers,
258 which may be selectively enabled in case of testing.
259 To enable a sub-driver,
260 list it in the kernel environment variable
261 .Va debug.acpi.enabled .
262 Multiple entries can be listed,
263 separated by a space.
265 ACPI sub-devices and features that can be enabled:
266 .Bl -tag -width ".Li sysresource"
272 It is also possible to avoid portions of the ACPI namespace which
273 may be causing problems, by listing the full path of the root of
274 the region to be avoided in the kernel environment variable
275 .Va debug.acpi.avoid.paths ,
277 .Va debug.acpi.avoid .
278 The latter also disables initialization of ACPI namespace as a
279 workaround for systems where not doing so crashes interpreter.
280 The object and all of its children will be ignored during the
281 bus/children scan of the namespace.
282 The ACPI CA code will still know about the avoided region.
284 To enable debugging output,
286 must be compiled with
287 .Cd "options ACPI_DEBUG" .
288 Debugging output is separated between layers and levels, where a layer is
289 a component of the ACPI subsystem, and a level is a particular kind
292 Both layers and levels are specified as a whitespace-separated list of
293 tokens, with layers listed in
296 .Va debug.acpi.level .
298 The first set of layers is for ACPI-CA components, and the second is for
301 The ACPI-CA layer descriptions include the prefix for the files they
303 The supported layers are:
305 .Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER"
306 .It Li ACPI_UTILITIES
307 Utility ("ut") functions
309 Hardware access ("hw")
314 .It Li ACPI_NAMESPACE
315 Namespace evaluation ("ns")
318 .It Li ACPI_DISPATCHER
319 Internal representation of interpreter state ("ds")
321 Execute AML methods ("ex")
322 .It Li ACPI_RESOURCES
323 Resource parsing ("rs")
324 .It Li ACPI_CA_DEBUGGER
325 Debugger implementation ("db", "dm")
326 .It Li ACPI_OS_SERVICES
327 Usermode support routines ("os")
328 .It Li ACPI_CA_DISASSEMBLER
329 Disassembler implementation (unused)
330 .It Li ACPI_ALL_COMPONENTS
331 All the above ACPI-CA components
332 .It Li ACPI_AC_ADAPTER
335 Control-method battery driver
337 ACPI, ISA, and PCI bus drivers
339 Power and sleep button driver
341 Embedded controller driver
345 Platform-specific driver for hotkeys, LED, etc.
347 Power resource driver
348 .It Li ACPI_PROCESSOR
354 .It Li ACPI_ALL_DRIVERS
360 The supported levels are:
362 .Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE"
364 Fatal error conditions
366 Warnings and potential problems
368 Initialization progress
369 .It Li ACPI_LV_DEBUG_OBJECT
372 General information and progress
373 .It Li ACPI_LV_ALL_EXCEPTIONS
374 All the previous levels
375 .It Li ACPI_LV_INIT_NAMES
378 .It Li ACPI_LV_DISPATCH
381 .It Li ACPI_LV_OPREGION
382 .It Li ACPI_LV_BFIELD
383 .It Li ACPI_LV_TABLES
384 .It Li ACPI_LV_VALUES
385 .It Li ACPI_LV_OBJECTS
386 .It Li ACPI_LV_RESOURCES
387 .It Li ACPI_LV_USER_REQUESTS
388 .It Li ACPI_LV_PACKAGE
389 .It Li ACPI_LV_VERBOSITY1
390 All the previous levels
391 .It Li ACPI_LV_ALLOCATIONS
392 .It Li ACPI_LV_FUNCTIONS
393 .It Li ACPI_LV_OPTIMIZATIONS
394 .It Li ACPI_LV_VERBOSITY2
397 .It Li ACPI_LV_THREADS
399 .It Li ACPI_LV_INTERRUPTS
400 .It Li ACPI_LV_VERBOSITY3
401 All the previous levels
402 .It Li ACPI_LV_AML_DISASSEMBLE
403 .It Li ACPI_LV_VERBOSE_INFO
404 .It Li ACPI_LV_FULL_TABLES
405 .It Li ACPI_LV_EVENTS
406 .It Li ACPI_LV_VERBOSE
408 .Qq Li ACPI_LV_VERBOSITY3
411 Selection of the appropriate layer and level values is important
412 to avoid massive amounts of debugging output.
413 For example, the following configuration is a good way to gather initial
415 It enables debug output for both ACPI-CA and the
417 driver, printing basic information about errors, warnings, and progress.
418 .Bd -literal -offset indent
419 debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS"
420 debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS"
423 Debugging output by the ACPI CA subsystem is prefixed with the
424 module name in lowercase, followed by a source line number.
427 code follows the same format, but
428 the module name is uppercased.
429 .Sh OVERRIDING YOUR BIOS BYTECODE
430 ACPI interprets bytecode named AML
431 (ACPI Machine Language)
432 provided by the BIOS vendor as a memory image at boot time.
433 Sometimes, the AML code contains a bug that does not appear when parsed
434 by the Microsoft implementation.
436 provides a way to override it with your own AML code to work around
437 or debug such problems.
438 Note that all AML in your DSDT and any SSDT tables is overridden.
440 In order to load your AML code, you must edit
441 .Pa /boot/loader.conf
442 and include the following lines.
443 .Bd -literal -offset indent
445 acpi_dsdt_name="/boot/acpi_dsdt.aml" # You may change this name.
448 In order to prepare your AML code, you will need the
452 utilities and some ACPI knowledge.
454 ACPI is only found and supported on i386/ia32, ia64, and x86_64.
458 .Xr acpi_thinkpad 4 ,
466 .%A "Compaq Computer Corporation"
467 .%A "Intel Corporation"
468 .%A "Microsoft Corporation"
469 .%A "Phoenix Technologies Ltd."
470 .%A "Toshiba Corporation"
472 .%T "Advanced Configuration and Power Interface Specification"
473 .%O http://acpi.info/spec.htm
477 The ACPI CA subsystem is developed and maintained by
478 Intel Architecture Labs.
480 The following people made notable contributions to the ACPI subsystem
484 .An Takanori Watanabe Aq takawata@jp.FreeBSD.org ,
485 .An Mitsuru IWASAKI Aq iwasaki@jp.FreeBSD.org ,
486 .An Munehiro Matsuda ,
488 the ACPI-jp mailing list at
489 .Aq acpi-jp@jp.FreeBSD.org ,
490 and many other contributors.
492 This manual page was written by
493 .An Michael Smith Aq msmith@FreeBSD.org .
497 driver is loaded as a module when it is already linked as part of the
498 kernel, odd things may happen.