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33 .Nd Advanced Configuration and Power Management support
37 .Cd "options ACPI_DEBUG"
41 driver provides support for the Intel/Microsoft/Compaq/Toshiba ACPI
43 This support includes platform hardware discovery (superseding the
44 PnP and PCI BIOS), as well as power management (superseding APM) and
46 ACPI core support is provided by the ACPI CA reference implementation
51 driver is automatically loaded by the
54 compiled into the kernel on platforms where ACPI is mandatory.
58 driver is intended to provide power management without user intervention.
59 Thus, some of these sysctls are controlled automatically by the
62 script, which can be configured via
64 If values are specified manually, they may be overridden.
65 .Bl -tag -width indent
66 .It Va hw.acpi.cpu.cx_usage
67 Debugging information listing the percent of total usage for each sleep state.
68 The values are reset when
69 .Va hw.acpi.cpu.cx_lowest
71 .It Va hw.acpi.cpu.cx_lowest
72 Lowest Cx state to use for idling the CPU.
73 A scheduling algorithm will select states between C1 and this setting
74 as system load dictates.
75 To enable ACPI CPU idling control,
76 .Va machdep.cpu_idle_hlt
78 .It Va hw.acpi.cpu.cx_supported
79 List of supported CPU idle states and their transition latency
81 Each state has a type (e.g., C2).
82 C1 is equivalent to the ia32 HLT instruction, C2 provides a deeper
83 sleep with the same semantics, and C3 provides the deepest sleep
84 but additionally requires bus mastering to be disabled.
85 States greater than C3 provide even more power savings with the same
86 semantics as the C3 state.
87 Deeper sleeps provide more power savings but increased transition
88 latency when an interrupt occurs.
91 Tunables can be set at the
93 prompt before booting the kernel or stored in
94 .Pa /boot/loader.conf .
95 .Bl -tag -width indent
97 Enables loading of a custom ACPI DSDT.
99 Name of the DSDT table to load, if loading is enabled.
100 .It Va debug.acpi.disabled
101 Selectively disables portions of ACPI for debugging purposes.
102 .It Va debug.acpi.quirks
103 Override any automatic quirks completely.
104 .It Va hint.acpi.0.disabled
105 Set this to 1 to disable all of ACPI.
106 If ACPI has been disabled on your system due to a blacklist entry for your
107 BIOS, you can set this to 0 to re-enable ACPI for testing.
108 .It Va hw.acpi.ec.poll_timeout
109 Delay in milliseconds to wait for the EC to respond.
110 Try increasing this number if you get the error
111 .Qq Li AE_NO_HARDWARE_RESPONSE .
112 .It Va hw.acpi.host_mem_start
113 Override the assumed memory starting address for PCI host bridges.
114 .It Va hw.acpi.pci.link.%d.%d.%d.irq
115 Override the interrupt to use.
116 .It Va hw.acpi.reset_video
117 Enables calling the VESA reset BIOS vector on the resume path.
118 Some graphic chips have problems such as LCD white-out after resume.
119 Try setting this to 0 if this causes problems for you.
120 .It Va hw.acpi.serialize_methods
121 Allow override of whether methods execute in parallel or not.
122 Enable this for serial behavior, which fixes
123 .Qq Li AE_ALREADY_EXISTS
125 AML that really cannot handle parallel method execution.
126 It is off by default since this breaks recursive methods and some IBMs use
128 .It Va hw.acpi.verbose
129 Turn on verbose debugging information about what ACPI is doing.
132 Since ACPI support on different platforms varies greatly, there are many
133 debugging and tuning options available.
135 For machines known not to work with
137 enabled, there is a BIOS blacklist.
138 Currently, the blacklist only controls whether
140 should be disabled or not.
141 In the future, it will have more granularity to control features (the
142 infrastructure for that is already there).
146 (for debugging purposes, etc.) on machines that are on the blacklist, set the
147 kernel environment variable
148 .Va hint.acpi.0.disabled
150 Before trying this, consider updating your BIOS to a more recent version that
151 may be compatible with ACPI.
155 driver completely, set the kernel environment variable
156 .Va hint.acpi.0.disabled
159 Some i386 machines totally fail to operate with some or all of ACPI disabled.
160 Other i386 machines fail with ACPI enabled.
161 Disabling all or part of ACPI on non-i386 platforms (i.e., platforms where
162 ACPI support is mandatory) may result in a non-functional system.
166 driver comprises a set of drivers, which may be selectively disabled
168 To disable a sub-driver, list it in the kernel
170 .Va debug.acpi.disabled .
171 Multiple entries can be listed, separated by a space.
173 ACPI sub-devices and features that can be disabled:
174 .Bl -tag -width ".Li sysresource"
176 Disable all ACPI features and devices.
182 Probes and attaches subdevices.
183 Disabling will avoid scanning the ACPI namespace entirely.
186 Attaches standard ACPI sub-drivers and devices enumerated in the
188 Disabling this has a similar effect to disabling
191 ACPI namespace will still be scanned.
194 Supports ACPI button devices (typically power and sleep buttons).
197 Control-method batteries device.
200 Supports CPU power-saving and speed-setting functions.
203 Supports the ACPI Embedded Controller interface, used to communicate
204 with embedded platform controllers.
207 Supports an ISA bus bridge defined in the ACPI namespace,
208 typically as a child of a PCI bus.
211 Supports an ACPI laptop lid switch, which typically puts a
216 Quirks automatically disable ACPI functionality based on the XSDT table's
217 OEM vendor name and revision date.
220 Supports Host to PCI bridges.
223 Performs PCI interrupt routing.
226 Pseudo-devices containing resources which ACPI claims.
229 Supports system cooling and heat management.
232 Implements a timecounter using the ACPI fixed-frequency timer.
235 It is also possible to avoid portions of the ACPI namespace which
236 may be causing problems, by listing the full path of the root of
237 the region to be avoided in the kernel environment variable
238 .Va debug.acpi.avoid .
239 The object and all of its children will be ignored during the
240 bus/children scan of the namespace.
241 The ACPI CA code will still know about the avoided region.
243 To enable debugging output,
245 must be compiled with
246 .Cd "options ACPI_DEBUG" .
247 Debugging output is separated between layers and levels, where a layer is
248 a component of the ACPI subsystem, and a level is a particular kind
251 Both layers and levels are specified as a whitespace-separated list of
252 tokens, with layers listed in
255 .Va debug.acpi.level .
257 The first set of layers is for ACPI-CA components, and the second is for
260 The ACPI-CA layer descriptions include the prefix for the files they
262 The supported layers are:
264 .Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER"
265 .It Li ACPI_UTILITIES
266 Utility ("ut") functions
268 Hardware access ("hw")
273 .It Li ACPI_NAMESPACE
274 Namespace evaluation ("ns")
277 .It Li ACPI_DISPATCHER
278 Internal representation of interpreter state ("ds")
280 Execute AML methods ("ex")
281 .It Li ACPI_RESOURCES
282 Resource parsing ("rs")
283 .It Li ACPI_CA_DEBUGGER
284 Debugger implementation ("db", "dm")
285 .It Li ACPI_OS_SERVICES
286 Usermode support routines ("os")
287 .It Li ACPI_CA_DISASSEMBLER
288 Disassembler implementation (unused)
289 .It Li ACPI_ALL_COMPONENTS
290 All the above ACPI-CA components
291 .It Li ACPI_AC_ADAPTER
294 Control-method battery driver
296 ACPI, ISA, and PCI bus drivers
298 Power and sleep button driver
300 Embedded controller driver
304 Platform-specific driver for hotkeys, LED, etc.
306 Power resource driver
307 .It Li ACPI_PROCESSOR
313 .It Li ACPI_ALL_DRIVERS
319 The supported levels are:
321 .Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE"
323 Fatal error conditions
325 Warnings and potential problems
327 Initialization progress
328 .It Li ACPI_LV_DEBUG_OBJECT
331 General information and progress
332 .It Li ACPI_LV_ALL_EXCEPTIONS
333 All the previous levels
334 .It Li ACPI_LV_INIT_NAMES
337 .It Li ACPI_LV_DISPATCH
340 .It Li ACPI_LV_OPREGION
341 .It Li ACPI_LV_BFIELD
342 .It Li ACPI_LV_TABLES
343 .It Li ACPI_LV_VALUES
344 .It Li ACPI_LV_OBJECTS
345 .It Li ACPI_LV_RESOURCES
346 .It Li ACPI_LV_USER_REQUESTS
347 .It Li ACPI_LV_PACKAGE
348 .It Li ACPI_LV_VERBOSITY1
349 All the previous levels
350 .It Li ACPI_LV_ALLOCATIONS
351 .It Li ACPI_LV_FUNCTIONS
352 .It Li ACPI_LV_OPTIMIZATIONS
353 .It Li ACPI_LV_VERBOSITY2
356 .It Li ACPI_LV_THREADS
358 .It Li ACPI_LV_INTERRUPTS
359 .It Li ACPI_LV_VERBOSITY3
360 All the previous levels
361 .It Li ACPI_LV_AML_DISASSEMBLE
362 .It Li ACPI_LV_VERBOSE_INFO
363 .It Li ACPI_LV_FULL_TABLES
364 .It Li ACPI_LV_EVENTS
365 .It Li ACPI_LV_VERBOSE
367 .Qq Li ACPI_LV_VERBOSITY3
370 Selection of the appropriate layer and level values is important
371 to avoid massive amounts of debugging output.
372 For example, the following configuration is a good way to gather initial
374 It enables debug output for both ACPI-CA and the
376 driver, printing basic information about errors, warnings, and progress.
377 .Bd -literal -offset indent
378 debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS"
379 debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS"
382 Debugging output by the ACPI CA subsystem is prefixed with the
383 module name in lowercase, followed by a source line number.
386 code follows the same format, but
387 the module name is uppercased.
388 .Sh OVERRIDING YOUR BIOS BYTECODE
389 ACPI interprets bytecode named AML
390 (ACPI Machine Language)
391 provided by the BIOS vendor as a memory image at boot time.
392 Sometimes, the AML code contains a bug that does not appear when parsed
393 by the Microsoft implementation.
395 provides a way to override it with your own AML code to work around
396 or debug such problems.
397 Note that all AML in your DSDT and any SSDT tables is overridden.
399 In order to load your AML code, you must edit
400 .Pa /boot/loader.conf
401 and include the following lines.
402 .Bd -literal -offset indent
404 acpi_dsdt_name="/boot/acpi_dsdt.aml" # You may change this name.
407 In order to prepare your AML code, you will need the
411 utilities and some ACPI knowledge.
413 ACPI is only found and supported on i386/ia32, ia64, and amd64.
424 .%A "Compaq Computer Corporation"
425 .%A "Intel Corporation"
426 .%A "Microsoft Corporation"
427 .%A "Phoenix Technologies Ltd."
428 .%A "Toshiba Corporation"
430 .%T "Advanced Configuration and Power Interface Specification"
431 .%O http://acpi.info/spec.htm
435 The ACPI CA subsystem is developed and maintained by
436 Intel Architecture Labs.
438 The following people made notable contributions to the ACPI subsystem
442 .An Takanori Watanabe Aq takawata@jp.FreeBSD.org ,
443 .An Mitsuru IWASAKI Aq iwasaki@jp.FreeBSD.org ,
444 .An Munehiro Matsuda ,
446 the ACPI-jp mailing list at
447 .Aq acpi-jp@jp.FreeBSD.org ,
448 and many other contributors.
450 This manual page was written by
451 .An Michael Smith Aq msmith@FreeBSD.org .
455 driver is loaded as a module when it is already linked as part of the
456 kernel, odd things may happen.