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 1.5 2006/09/13 09:08:50 swildner Exp $
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 the ACPI Embedded Controller interface, used to communicate
209 with embedded platform controllers.
212 Supports an ISA bus bridge defined in the ACPI namespace,
213 typically as a child of a PCI bus.
216 Supports an ACPI laptop lid switch, which typically puts a
221 Quirks automatically disable ACPI functionality based on the XSDT table's
222 OEM vendor name and revision date.
225 Supports Host to PCI bridges.
228 Performs PCI interrupt routing.
231 Pseudo-devices containing resources which ACPI claims.
234 Supports system cooling and heat management.
237 Implements a timecounter using the ACPI fixed-frequency timer.
240 Supports acpi_video which may conflict with agp device.
243 It is also possible to avoid portions of the ACPI namespace which
244 may be causing problems, by listing the full path of the root of
245 the region to be avoided in the kernel environment variable
246 .Va debug.acpi.avoid.paths ,
248 .Va debug.acpi.avoid .
249 The latter also disables initialization of ACPI namespace as a
250 workaround for systems where not doing so crashes interpreter.
251 The object and all of its children will be ignored during the
252 bus/children scan of the namespace.
253 The ACPI CA code will still know about the avoided region.
255 To enable debugging output,
257 must be compiled with
258 .Cd "options ACPI_DEBUG" .
259 Debugging output is separated between layers and levels, where a layer is
260 a component of the ACPI subsystem, and a level is a particular kind
263 Both layers and levels are specified as a whitespace-separated list of
264 tokens, with layers listed in
267 .Va debug.acpi.level .
269 The first set of layers is for ACPI-CA components, and the second is for
272 The ACPI-CA layer descriptions include the prefix for the files they
274 The supported layers are:
276 .Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER"
277 .It Li ACPI_UTILITIES
278 Utility ("ut") functions
280 Hardware access ("hw")
285 .It Li ACPI_NAMESPACE
286 Namespace evaluation ("ns")
289 .It Li ACPI_DISPATCHER
290 Internal representation of interpreter state ("ds")
292 Execute AML methods ("ex")
293 .It Li ACPI_RESOURCES
294 Resource parsing ("rs")
295 .It Li ACPI_CA_DEBUGGER
296 Debugger implementation ("db", "dm")
297 .It Li ACPI_OS_SERVICES
298 Usermode support routines ("os")
299 .It Li ACPI_CA_DISASSEMBLER
300 Disassembler implementation (unused)
301 .It Li ACPI_ALL_COMPONENTS
302 All the above ACPI-CA components
303 .It Li ACPI_AC_ADAPTER
306 Control-method battery driver
308 ACPI, ISA, and PCI bus drivers
310 Power and sleep button driver
312 Embedded controller driver
316 Platform-specific driver for hotkeys, LED, etc.
318 Power resource driver
319 .It Li ACPI_PROCESSOR
325 .It Li ACPI_ALL_DRIVERS
331 The supported levels are:
333 .Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE"
335 Fatal error conditions
337 Warnings and potential problems
339 Initialization progress
340 .It Li ACPI_LV_DEBUG_OBJECT
343 General information and progress
344 .It Li ACPI_LV_ALL_EXCEPTIONS
345 All the previous levels
346 .It Li ACPI_LV_INIT_NAMES
349 .It Li ACPI_LV_DISPATCH
352 .It Li ACPI_LV_OPREGION
353 .It Li ACPI_LV_BFIELD
354 .It Li ACPI_LV_TABLES
355 .It Li ACPI_LV_VALUES
356 .It Li ACPI_LV_OBJECTS
357 .It Li ACPI_LV_RESOURCES
358 .It Li ACPI_LV_USER_REQUESTS
359 .It Li ACPI_LV_PACKAGE
360 .It Li ACPI_LV_VERBOSITY1
361 All the previous levels
362 .It Li ACPI_LV_ALLOCATIONS
363 .It Li ACPI_LV_FUNCTIONS
364 .It Li ACPI_LV_OPTIMIZATIONS
365 .It Li ACPI_LV_VERBOSITY2
368 .It Li ACPI_LV_THREADS
370 .It Li ACPI_LV_INTERRUPTS
371 .It Li ACPI_LV_VERBOSITY3
372 All the previous levels
373 .It Li ACPI_LV_AML_DISASSEMBLE
374 .It Li ACPI_LV_VERBOSE_INFO
375 .It Li ACPI_LV_FULL_TABLES
376 .It Li ACPI_LV_EVENTS
377 .It Li ACPI_LV_VERBOSE
379 .Qq Li ACPI_LV_VERBOSITY3
382 Selection of the appropriate layer and level values is important
383 to avoid massive amounts of debugging output.
384 For example, the following configuration is a good way to gather initial
386 It enables debug output for both ACPI-CA and the
388 driver, printing basic information about errors, warnings, and progress.
389 .Bd -literal -offset indent
390 debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS"
391 debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS"
394 Debugging output by the ACPI CA subsystem is prefixed with the
395 module name in lowercase, followed by a source line number.
398 code follows the same format, but
399 the module name is uppercased.
400 .Sh OVERRIDING YOUR BIOS BYTECODE
401 ACPI interprets bytecode named AML
402 (ACPI Machine Language)
403 provided by the BIOS vendor as a memory image at boot time.
404 Sometimes, the AML code contains a bug that does not appear when parsed
405 by the Microsoft implementation.
407 provides a way to override it with your own AML code to work around
408 or debug such problems.
409 Note that all AML in your DSDT and any SSDT tables is overridden.
411 In order to load your AML code, you must edit
412 .Pa /boot/loader.conf
413 and include the following lines.
414 .Bd -literal -offset indent
416 acpi_dsdt_name="/boot/acpi_dsdt.aml" # You may change this name.
419 In order to prepare your AML code, you will need the
423 utilities and some ACPI knowledge.
425 ACPI is only found and supported on i386/ia32, ia64, and amd64.
436 .%A "Compaq Computer Corporation"
437 .%A "Intel Corporation"
438 .%A "Microsoft Corporation"
439 .%A "Phoenix Technologies Ltd."
440 .%A "Toshiba Corporation"
442 .%T "Advanced Configuration and Power Interface Specification"
443 .%O http://acpi.info/spec.htm
447 The ACPI CA subsystem is developed and maintained by
448 Intel Architecture Labs.
450 The following people made notable contributions to the ACPI subsystem
454 .An Takanori Watanabe Aq takawata@jp.FreeBSD.org ,
455 .An Mitsuru IWASAKI Aq iwasaki@jp.FreeBSD.org ,
456 .An Munehiro Matsuda ,
458 the ACPI-jp mailing list at
459 .Aq acpi-jp@jp.FreeBSD.org ,
460 and many other contributors.
462 This manual page was written by
463 .An Michael Smith Aq msmith@FreeBSD.org .
467 driver is loaded as a module when it is already linked as part of the
468 kernel, odd things may happen.