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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.max_threads
103 Specify the number of task threads that are started on boot.
104 Limiting this to 1 may help work around various BIOSes that cannot
105 handle parallel requests.
106 The default value is 3.
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 .
247 The object and all of its children will be ignored during the
248 bus/children scan of the namespace.
249 The ACPI CA code will still know about the avoided region.
251 To enable debugging output,
253 must be compiled with
254 .Cd "options ACPI_DEBUG" .
255 Debugging output is separated between layers and levels, where a layer is
256 a component of the ACPI subsystem, and a level is a particular kind
259 Both layers and levels are specified as a whitespace-separated list of
260 tokens, with layers listed in
263 .Va debug.acpi.level .
265 The first set of layers is for ACPI-CA components, and the second is for
268 The ACPI-CA layer descriptions include the prefix for the files they
270 The supported layers are:
272 .Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER"
273 .It Li ACPI_UTILITIES
274 Utility ("ut") functions
276 Hardware access ("hw")
281 .It Li ACPI_NAMESPACE
282 Namespace evaluation ("ns")
285 .It Li ACPI_DISPATCHER
286 Internal representation of interpreter state ("ds")
288 Execute AML methods ("ex")
289 .It Li ACPI_RESOURCES
290 Resource parsing ("rs")
291 .It Li ACPI_CA_DEBUGGER
292 Debugger implementation ("db", "dm")
293 .It Li ACPI_OS_SERVICES
294 Usermode support routines ("os")
295 .It Li ACPI_CA_DISASSEMBLER
296 Disassembler implementation (unused)
297 .It Li ACPI_ALL_COMPONENTS
298 All the above ACPI-CA components
299 .It Li ACPI_AC_ADAPTER
302 Control-method battery driver
304 ACPI, ISA, and PCI bus drivers
306 Power and sleep button driver
308 Embedded controller driver
312 Platform-specific driver for hotkeys, LED, etc.
314 Power resource driver
315 .It Li ACPI_PROCESSOR
321 .It Li ACPI_ALL_DRIVERS
327 The supported levels are:
329 .Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE"
331 Fatal error conditions
333 Warnings and potential problems
335 Initialization progress
336 .It Li ACPI_LV_DEBUG_OBJECT
339 General information and progress
340 .It Li ACPI_LV_ALL_EXCEPTIONS
341 All the previous levels
342 .It Li ACPI_LV_INIT_NAMES
345 .It Li ACPI_LV_DISPATCH
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
357 All 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
364 .It Li ACPI_LV_THREADS
366 .It Li ACPI_LV_INTERRUPTS
367 .It Li ACPI_LV_VERBOSITY3
368 All 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
375 .Qq Li ACPI_LV_VERBOSITY3
378 Selection of the appropriate layer and level values is important
379 to avoid massive amounts of debugging output.
380 For example, the following configuration is a good way to gather initial
382 It enables debug output for both ACPI-CA and the
384 driver, printing basic information about errors, warnings, and progress.
385 .Bd -literal -offset indent
386 debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS"
387 debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS"
390 Debugging output by the ACPI CA subsystem is prefixed with the
391 module name in lowercase, followed by a source line number.
394 code follows the same format, but
395 the module name is uppercased.
396 .Sh OVERRIDING YOUR BIOS BYTECODE
397 ACPI interprets bytecode named AML
398 (ACPI Machine Language)
399 provided by the BIOS vendor as a memory image at boot time.
400 Sometimes, the AML code contains a bug that does not appear when parsed
401 by the Microsoft implementation.
403 provides a way to override it with your own AML code to work around
404 or debug such problems.
405 Note that all AML in your DSDT and any SSDT tables is overridden.
407 In order to load your AML code, you must edit
408 .Pa /boot/loader.conf
409 and include the following lines.
410 .Bd -literal -offset indent
412 acpi_dsdt_name="/boot/acpi_dsdt.aml" # You may change this name.
415 In order to prepare your AML code, you will need the
419 utilities and some ACPI knowledge.
421 ACPI is only found and supported on i386/ia32, ia64, and amd64.
432 .%A "Compaq Computer Corporation"
433 .%A "Intel Corporation"
434 .%A "Microsoft Corporation"
435 .%A "Phoenix Technologies Ltd."
436 .%A "Toshiba Corporation"
438 .%T "Advanced Configuration and Power Interface Specification"
439 .%O http://acpi.info/spec.htm
443 The ACPI CA subsystem is developed and maintained by
444 Intel Architecture Labs.
446 The following people made notable contributions to the ACPI subsystem
450 .An Takanori Watanabe Aq takawata@jp.FreeBSD.org ,
451 .An Mitsuru IWASAKI Aq iwasaki@jp.FreeBSD.org ,
452 .An Munehiro Matsuda ,
454 the ACPI-jp mailing list at
455 .Aq acpi-jp@jp.FreeBSD.org ,
456 and many other contributors.
458 This manual page was written by
459 .An Michael Smith Aq msmith@FreeBSD.org .
463 driver is loaded as a module when it is already linked as part of the
464 kernel, odd things may happen.