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_QUIRK_VMWARE"
39 .Cd "options ACPI_DEBUG"
43 driver provides support for the Intel/Microsoft/Compaq/Toshiba ACPI
45 This support includes platform hardware discovery (superseding the
46 PnP and PCI BIOS), as well as power management (superseding APM) and
48 ACPI core support is provided by the ACPI CA reference implementation
51 It was observed that when running
53 as a guest in VMware 5.5.1 under SMP conditions, VMware's ACPI-fast24
54 timer runs roughly 65 times too fast.
57 option can be specified in the kernel configuration file in order to
62 driver is automatically loaded by the
65 compiled into the kernel on platforms where ACPI is mandatory.
69 driver is intended to provide power management without user intervention.
70 Thus, some of these sysctls are controlled automatically by the
73 script, which can be configured via
75 If values are specified manually, they may be overridden.
76 .Bl -tag -width indent
77 .It Va hw.acpi.cpu.cx_usage
78 Debugging information listing the percent of total usage for each sleep state.
79 The values are reset when
80 .Va hw.acpi.cpu.cx_lowest
82 .It Va hw.acpi.cpu.cx_lowest
83 Lowest Cx state to use for idling the CPU.
84 A scheduling algorithm will select states between C1 and this setting
85 as system load dictates.
86 To enable ACPI CPU idling control,
87 .Va machdep.cpu_idle_hlt
89 .It Va hw.acpi.cpu.cx_supported
90 List of supported CPU idle states and their transition latency
92 Each state has a type (e.g., C2).
93 C1 is equivalent to the ia32 HLT instruction, C2 provides a deeper
94 sleep with the same semantics, and C3 provides the deepest sleep
95 but additionally requires bus mastering to be disabled.
96 States greater than C3 provide even more power savings with the same
97 semantics as the C3 state.
98 Deeper sleeps provide more power savings but increased transition
99 latency when an interrupt occurs.
102 Tunables can be set at the
104 prompt before booting the kernel or stored in
105 .Pa /boot/loader.conf .
106 .Bl -tag -width indent
107 .It Va acpi_dsdt_load
108 Enables loading of a custom ACPI DSDT.
109 .It Va acpi_dsdt_name
110 Name of the DSDT table to load, if loading is enabled.
111 .It Va debug.acpi.disabled
112 Selectively disables portions of ACPI that are enabled by default, for
114 .It Va debug.acpi.enabled
115 Selectively enables portions of ACPI that are disabled by default, for
117 .It Va debug.acpi.quirks
118 Override any automatic quirks completely.
119 .It Va hint.acpi.0.disabled
120 Set this to 1 to disable all of ACPI.
121 If ACPI has been disabled on your system due to a blacklist entry for your
122 BIOS, you can set this to 0 to re-enable ACPI for testing.
123 .It Va hw.acpi.ec.poll_timeout
124 Delay in milliseconds to wait for the EC to respond.
125 Try increasing this number if you get the error
126 .Qq Li AE_NO_HARDWARE_RESPONSE .
127 .It Va hw.acpi.host_mem_start
128 Override the assumed memory starting address for PCI host bridges.
129 .It Va hw.acpi.pci.link.%d.%d.%d.irq
130 Override the interrupt to use.
131 .It Va hw.acpi.reset_video
132 Enables calling the VESA reset BIOS vector on the resume path.
133 Some graphic chips have problems such as LCD white-out after resume.
134 Try setting this to 0 if this causes problems for you.
135 .It Va hw.acpi.serialize_methods
136 Allow override of whether methods execute in parallel or not.
137 Enable this for serial behavior, which fixes
138 .Qq Li AE_ALREADY_EXISTS
140 AML that really cannot handle parallel method execution.
141 It is off by default since this breaks recursive methods and some IBMs use
143 .It Va hw.acpi.verbose
144 Turn on verbose debugging information about what ACPI is doing.
147 Since ACPI support on different platforms varies greatly, there are many
148 debugging and tuning options available.
150 For machines known not to work with
152 enabled, there is a BIOS blacklist.
153 Currently, the blacklist only controls whether
155 should be disabled or not.
156 In the future, it will have more granularity to control features (the
157 infrastructure for that is already there).
161 (for debugging purposes, etc.) on machines that are on the blacklist, set the
162 kernel environment variable
163 .Va hint.acpi.0.disabled
165 Before trying this, consider updating your BIOS to a more recent version that
166 may be compatible with ACPI.
170 driver completely, set the kernel environment variable
171 .Va hint.acpi.0.disabled
174 Some i386 machines totally fail to operate with some or all of ACPI disabled.
175 Other i386 machines fail with ACPI enabled.
176 Disabling all or part of ACPI on non-i386 platforms (i.e., platforms where
177 ACPI support is mandatory) may result in a non-functional system.
181 driver comprises a set of drivers, which may be selectively disabled
183 To disable a sub-driver, list it in the kernel
185 .Va debug.acpi.disabled .
186 Multiple entries can be listed, separated by a space.
188 ACPI sub-devices and features that can be disabled:
189 .Bl -tag -width ".Li sysresource"
191 Disable all ACPI features and devices.
197 Probes and attaches subdevices.
198 Disabling will avoid scanning the ACPI namespace entirely.
201 Attaches standard ACPI sub-drivers and devices enumerated in the
203 Disabling this has a similar effect to disabling
206 ACPI namespace will still be scanned.
209 Supports ACPI button devices (typically power and sleep buttons).
212 Control-method batteries device.
215 Supports CPU power-saving and speed-setting functions.
218 Supports CPU power-saving.
221 will also disable this device.
224 Supports CPU speed-setting.
227 will also disable this device.
230 Supports the ACPI Embedded Controller interface, used to communicate
231 with embedded platform controllers.
234 Supports an ISA bus bridge defined in the ACPI namespace,
235 typically as a child of a PCI bus.
238 Supports an ACPI laptop lid switch, which typically puts a
243 Quirks automatically disable ACPI functionality based on the XSDT table's
244 OEM vendor name and revision date.
247 Supports Host to PCI bridges.
250 Performs PCI interrupt routing.
253 Pseudo-devices containing resources which ACPI claims.
256 Supports system cooling and heat management.
259 Implements a timecounter using the ACPI fixed-frequency timer.
262 Supports acpi_video which may conflict with agp device.
267 driver comprises a set of drivers,
268 which may be selectively enabled in case of testing.
269 To enable a sub-driver,
270 list it in the kernel environment variable
271 .Va debug.acpi.enabled .
272 Multiple entries can be listed,
273 separated by a space.
275 ACPI sub-devices and features that can be enabled:
276 .Bl -tag -width ".Li sysresource"
282 It is also possible to avoid portions of the ACPI namespace which
283 may be causing problems, by listing the full path of the root of
284 the region to be avoided in the kernel environment variable
285 .Va debug.acpi.avoid.paths ,
287 .Va debug.acpi.avoid .
288 The latter also disables initialization of ACPI namespace as a
289 workaround for systems where not doing so crashes interpreter.
290 The object and all of its children will be ignored during the
291 bus/children scan of the namespace.
292 The ACPI CA code will still know about the avoided region.
294 To enable debugging output,
296 must be compiled with
297 .Cd "options ACPI_DEBUG" .
298 Debugging output is separated between layers and levels, where a layer is
299 a component of the ACPI subsystem, and a level is a particular kind
302 Both layers and levels are specified as a whitespace-separated list of
303 tokens, with layers listed in
306 .Va debug.acpi.level .
308 The first set of layers is for ACPI-CA components, and the second is for
311 The ACPI-CA layer descriptions include the prefix for the files they
313 The supported layers are:
315 .Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER"
316 .It Li ACPI_UTILITIES
317 Utility ("ut") functions
319 Hardware access ("hw")
324 .It Li ACPI_NAMESPACE
325 Namespace evaluation ("ns")
328 .It Li ACPI_DISPATCHER
329 Internal representation of interpreter state ("ds")
331 Execute AML methods ("ex")
332 .It Li ACPI_RESOURCES
333 Resource parsing ("rs")
334 .It Li ACPI_CA_DEBUGGER
335 Debugger implementation ("db", "dm")
336 .It Li ACPI_OS_SERVICES
337 Usermode support routines ("os")
338 .It Li ACPI_CA_DISASSEMBLER
339 Disassembler implementation (unused)
340 .It Li ACPI_ALL_COMPONENTS
341 All the above ACPI-CA components
342 .It Li ACPI_AC_ADAPTER
345 Control-method battery driver
347 ACPI, ISA, and PCI bus drivers
349 Power and sleep button driver
351 Embedded controller driver
355 Platform-specific driver for hotkeys, LED, etc.
357 Power resource driver
358 .It Li ACPI_PROCESSOR
364 .It Li ACPI_ALL_DRIVERS
370 The supported levels are:
372 .Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE"
374 Fatal error conditions
376 Warnings and potential problems
378 Initialization progress
379 .It Li ACPI_LV_DEBUG_OBJECT
382 General information and progress
383 .It Li ACPI_LV_ALL_EXCEPTIONS
384 All the previous levels
385 .It Li ACPI_LV_INIT_NAMES
388 .It Li ACPI_LV_DISPATCH
391 .It Li ACPI_LV_OPREGION
392 .It Li ACPI_LV_BFIELD
393 .It Li ACPI_LV_TABLES
394 .It Li ACPI_LV_VALUES
395 .It Li ACPI_LV_OBJECTS
396 .It Li ACPI_LV_RESOURCES
397 .It Li ACPI_LV_USER_REQUESTS
398 .It Li ACPI_LV_PACKAGE
399 .It Li ACPI_LV_VERBOSITY1
400 All the previous levels
401 .It Li ACPI_LV_ALLOCATIONS
402 .It Li ACPI_LV_FUNCTIONS
403 .It Li ACPI_LV_OPTIMIZATIONS
404 .It Li ACPI_LV_VERBOSITY2
407 .It Li ACPI_LV_THREADS
409 .It Li ACPI_LV_INTERRUPTS
410 .It Li ACPI_LV_VERBOSITY3
411 All the previous levels
412 .It Li ACPI_LV_AML_DISASSEMBLE
413 .It Li ACPI_LV_VERBOSE_INFO
414 .It Li ACPI_LV_FULL_TABLES
415 .It Li ACPI_LV_EVENTS
416 .It Li ACPI_LV_VERBOSE
418 .Qq Li ACPI_LV_VERBOSITY3
421 Selection of the appropriate layer and level values is important
422 to avoid massive amounts of debugging output.
423 For example, the following configuration is a good way to gather initial
425 It enables debug output for both ACPI-CA and the
427 driver, printing basic information about errors, warnings, and progress.
428 .Bd -literal -offset indent
429 debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS"
430 debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS"
433 Debugging output by the ACPI CA subsystem is prefixed with the
434 module name in lowercase, followed by a source line number.
437 code follows the same format, but
438 the module name is uppercased.
439 .Sh OVERRIDING YOUR BIOS BYTECODE
440 ACPI interprets bytecode named AML
441 (ACPI Machine Language)
442 provided by the BIOS vendor as a memory image at boot time.
443 Sometimes, the AML code contains a bug that does not appear when parsed
444 by the Microsoft implementation.
446 provides a way to override it with your own AML code to work around
447 or debug such problems.
448 Note that all AML in your DSDT and any SSDT tables is overridden.
450 In order to load your AML code, you must edit
451 .Pa /boot/loader.conf
452 and include the following lines.
453 .Bd -literal -offset indent
455 acpi_dsdt_name="/boot/acpi_dsdt.aml" # You may change this name.
458 In order to prepare your AML code, you will need the
462 utilities and some ACPI knowledge.
464 ACPI is only found and supported on i386/ia32, ia64, and amd64.
468 .Xr acpi_thinkpad 4 ,
476 .%A "Compaq Computer Corporation"
477 .%A "Intel Corporation"
478 .%A "Microsoft Corporation"
479 .%A "Phoenix Technologies Ltd."
480 .%A "Toshiba Corporation"
482 .%T "Advanced Configuration and Power Interface Specification"
483 .%O http://acpi.info/spec.htm
487 The ACPI CA subsystem is developed and maintained by
488 Intel Architecture Labs.
490 The following people made notable contributions to the ACPI subsystem
494 .An Takanori Watanabe Aq takawata@jp.FreeBSD.org ,
495 .An Mitsuru IWASAKI Aq iwasaki@jp.FreeBSD.org ,
496 .An Munehiro Matsuda ,
498 the ACPI-jp mailing list at
499 .Aq acpi-jp@jp.FreeBSD.org ,
500 and many other contributors.
502 This manual page was written by
503 .An Michael Smith Aq msmith@FreeBSD.org .
507 driver is loaded as a module when it is already linked as part of the
508 kernel, odd things may happen.