2 .\" Copyright (c) 2001 Michael Smith
3 .\" All rights reserved.
5 .\" Redistribution and use in source and binary forms, with or without
6 .\" modification, are permitted provided that the following conditions
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14 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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16 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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23 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 .\" $FreeBSD: src/share/man/man4/acpi.4,v 1.61.8.1 2009/04/15 03:14:26 kensmith Exp $
33 .Nd Advanced Configuration and Power Management support
37 .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 ACPICA reference implementation
52 driver is usually compiled into the kernel, and it is automatically loaded
55 if it is not in the kernel configuration file.
56 The loader menu provides a menu item to boot without ACPI.
63 driver is intended to provide power management without user intervention.
64 If the default settings are not optimal, the following sysctls can be
65 used to modify or monitor
68 .Bl -tag -width indent
69 .It Va debug.acpi.enable_debug_objects
70 Enable dumping Debug objects without
71 .Cd "options ACPI_DEBUG" .
72 Default is 0, ignore Debug objects.
74 AC line state (1 means online, 0 means on battery power).
75 .It Va hw.acpi.cpu.cx_usage
76 Debugging information listing the percent of total usage for each sleep state.
77 The values are reset when
78 .Va hw.acpi.cpu.cx_lowest
80 .It Va hw.acpi.cpu.cx_lowest
81 Lowest Cx state to use for idling the CPU.
82 A scheduling algorithm will select states between
85 as system load dictates.
86 To enable ACPI CPU idling control,
87 .Va machdep.cpu_idle_hlt
88 must be set to 2 (the default value).
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.,
95 is equivalent to the ia32
100 sleep with the same semantics, and
102 provides the deepest sleep
103 but additionally requires bus mastering to be disabled.
106 provide even more power savings with the same
110 Deeper sleeps provide more power savings but increased transition
111 latency when an interrupt occurs.
112 .It Va hw.acpi.disable_on_reboot
113 Disable ACPI during the reboot process.
114 Most systems reboot fine with ACPI still enabled, but some require
115 exiting to legacy mode first.
116 Default is 0, leave ACPI enabled.
117 .It Va hw.acpi.handle_reboot
118 Use the ACPI Reset Register capability to reboot the system.
119 Default is 0, use legacy reboot support.
120 Some newer systems require use of this register, while some only work
121 with legacy rebooting support.
122 .It Va hw.acpi.lid_switch_state
124 .Pq Li S1 Ns \[en] Ns Li S5
125 to enter when the lid switch (i.e., a notebook screen) is closed.
129 .It Va hw.acpi.power_button_state
131 .Pq Li S1 Ns \[en] Ns Li S5
132 to enter when the power button is pressed.
136 .It Va hw.acpi.reset_video
137 Reset the video adapter from real mode during the resume path.
138 Some systems need this help, others have display problems if it is enabled.
139 Default is 0 (disabled).
140 .It Va hw.acpi.s4bios
141 Indicate whether the system supports
143 This means that the BIOS can handle all the functions of suspending the
145 Otherwise, the OS is responsible for suspending to disk
147 Most current systems do not support
149 .It Va hw.acpi.sleep_button_state
151 .Pq Li S1 Ns \[en] Ns Li S5
152 to enter when the sleep button is pressed.
153 This is usually a special function button on the keyboard.
157 .It Va hw.acpi.sleep_delay
158 Wait this number of seconds between preparing the system to suspend and
159 actually entering the suspend state.
161 .It Va hw.acpi.supported_sleep_state
163 .Pq Li S1 Ns \[en] Ns Li S5
164 supported by the BIOS.
165 .Bl -tag -width indent
167 Quick suspend to RAM.
168 The CPU enters a lower power state, but most peripherals are left running.
170 Lower power state than
172 but with the same basic characteristics.
173 Not supported by many systems.
176 Most devices are powered off, and the system stops running except for
180 All devices are powered off, and the system stops running.
181 When resuming, the system starts as if from a cold power on.
188 System shuts down cleanly and powers off.
190 .It Va hw.acpi.verbose
191 Enable verbose printing from the various ACPI subsystems.
194 Tunables can be set at the
196 prompt before booting the kernel or stored in
197 .Pa /boot/loader.conf .
198 Many of these tunables also have a matching
200 entry for access after boot.
201 .Bl -tag -width indent
202 .It Va acpi_dsdt_load
203 Enables loading of a custom ACPI DSDT.
204 .It Va acpi_dsdt_name
205 Name of the DSDT table to load, if loading is enabled.
208 .It Va debug.acpi.allow_method_calls
211 utility can be used to directly call ACPI methods for debugging and
213 .It Va debug.acpi.disabled
214 Selectively disables portions of ACPI that are enabled by default, for
216 .It Va debug.acpi.enabled
217 Selectively enables portions of ACPI that are disabled by default, for
219 .It Va debug.acpi.facs_addr32
220 Favor 32-bit FACS table addresses over the 64-bit addresses.
221 .It Va debug.acpi.fadt_addr32
222 Favor 32-bit FADT register addresses over the 64-bit addresses.
223 .It Va debug.acpi.ignore_xsdt
224 Ignore the XSDT, forcing the use of the RSDT.
225 .It Va debug.acpi.interpreter_slack
226 Enable less strict ACPI implementations.
227 Default is 1, ignore common BIOS mistakes.
228 .It Va debug.acpi.max_threads
229 Specify the number of task threads that are started on boot.
230 Limiting this to 1 may help work around various BIOSes that cannot
231 handle parallel requests.
232 The default value is 3.
233 .It Va debug.acpi.quirks
234 Override any automatic quirks completely.
235 .It Va debug.acpi.resume_beep
236 Beep the PC speaker on resume.
237 This can help diagnose suspend/resume problems.
238 Default is 0 (disabled).
239 .It Va hint.acpi.0.disabled
240 Set this to 1 to disable all of ACPI.
241 If ACPI has been disabled on your system due to a blacklist entry for your
242 BIOS, you can set this to 0 to re-enable ACPI for testing.
243 .It Va hw.acpi.ec.poll_timeout
244 Delay in milliseconds to wait for the EC to respond.
245 Try increasing this number if you get the error
246 .Qq Li AE_NO_HARDWARE_RESPONSE .
247 .It Va hw.acpi.host_mem_start
248 Override the assumed memory starting address for PCI host bridges.
249 .It Va hw.acpi.install_interface , hw.acpi.remove_interface
250 Install or remove OS interface(s) to control the return value of the
253 When an OS interface is specified in
254 .Va hw.acpi.install_interface ,
257 query for the interface returns it is
259 Conversely, when an OS interface is specified in
260 .Va hw.acpi.remove_interface ,
265 Multiple interfaces can be specified in a comma-separated list and
266 any leading white spaces will be ignored.
268 .Qq Li FreeBSD, Linux
269 is a valid list of two interfaces
273 .It Va hw.acpi.reset_video
274 Enables calling the VESA reset BIOS vector on the resume path.
275 This can fix some graphics cards that have problems such as LCD white-out
277 Default is 0 (disabled).
278 .It Va hw.acpi.auto_serialize_methods
279 Auto-serialization of control methods to proactively prevent problems with
280 ill-behaved reentrant control methods that create named ACPI objects.
281 Default is 1 (enabled).
282 .It Va hw.acpi.verbose
283 Turn on verbose debugging information about what ACPI is doing.
284 .It Va hw.pci.link.%s.%d.irq
285 Override the interrupt to use for this link and index.
286 This capability should be used carefully, and only if a device is not
291 is the name of the link (e.g., LNKA).
293 is the resource index when the link supports multiple IRQs.
294 Most PCI links only have one IRQ resource, so the below form should be used.
295 .It Va hw.pci.link.%s.irq
296 Override the interrupt to use.
297 This capability should be used carefully, and only if a device is not
302 is the name of the link (e.g., LNKA).
305 Since ACPI support on different platforms varies greatly, there are many
306 debugging and tuning options available.
308 For machines known not to work with
310 enabled, there is a BIOS blacklist.
311 Currently, the blacklist only controls whether
313 should be disabled or not.
314 In the future, it will have more granularity to control features (the
315 infrastructure for that is already there).
319 (for debugging purposes, etc.) on machines that are on the blacklist, set the
320 kernel environment variable
321 .Va hint.acpi.0.disabled
323 Before trying this, consider updating your BIOS to a more recent version that
324 may be compatible with ACPI.
328 driver completely, set the kernel environment variable
329 .Va hint.acpi.0.disabled
332 Disabling all or part of ACPI may result in a non-functional system.
336 driver comprises a set of drivers, which may be selectively disabled
338 To disable a sub-driver, list it in the kernel
340 .Va debug.acpi.disabled .
341 Multiple entries can be listed, separated by a space.
343 ACPI sub-devices and features that can be disabled:
344 .Bl -tag -width ".Li sysresource"
346 Disable all ACPI features and devices.
352 Probes and attaches subdevices.
353 Disabling will avoid scanning the ACPI namespace entirely.
356 Attaches standard ACPI sub-drivers and devices enumerated in the
358 Disabling this has a similar effect to disabling
361 ACPI namespace will still be scanned.
364 Supports ACPI button devices (typically power and sleep buttons).
367 Control-method batteries device.
370 Supports CPU power-saving and speed-setting functions.
373 Supports CPU power-saving.
376 will also disable this device.
379 Supports CPU speed-setting.
382 will also disable this device.
385 Docking station device.
388 Supports the ACPI Embedded Controller interface, used to communicate
389 with embedded platform controllers.
392 Supports the High Precision Event Timer.
395 Supports an ISA bus bridge defined in the ACPI namespace,
396 typically as a child of a PCI bus.
399 Supports an ACPI laptop lid switch, which typically puts a
404 Quirks automatically disable ACPI functionality based on the XSDT table's
405 OEM vendor name and revision date.
408 Supports Host to PCI bridges.
411 Performs PCI interrupt routing.
414 Pseudo-devices containing resources which ACPI claims.
417 Supports system cooling and heat management.
420 Implements a timecounter using the ACPI fixed-frequency timer.
425 which may conflict with
432 .\"driver comprises a set of drivers,
433 .\"which may be selectively enabled in case of testing.
434 .\"To enable a sub-driver,
435 .\"list it in the kernel environment variable
436 .\".Va debug.acpi.enabled .
437 .\"Multiple entries can be listed,
438 .\"separated by a space.
440 .\"ACPI sub-devices and features that can be enabled:
441 .\".Bl -tag -width ".Li sysresource"
445 It is also possible to avoid portions of the ACPI namespace which
446 may be causing problems, by listing the full path of the root of
447 the region to be avoided in the kernel environment variable
448 .Va debug.acpi.avoid .
449 The object and all of its children will be ignored during the
450 bus/children scan of the namespace.
451 The ACPICA code will still know about the avoided region.
453 To enable debugging output,
455 must be compiled with
456 .Cd "options ACPI_DEBUG" .
457 Debugging output is separated between layers and levels, where a layer is
458 a component of the ACPI subsystem, and a level is a particular kind
461 Both layers and levels are specified as a whitespace-separated list of
462 tokens, with layers listed in
465 .Va debug.acpi.level .
467 The first set of layers is for ACPICA components, and the second is for
470 The ACPICA layer descriptions include the prefix for the files they
472 The supported layers are:
474 .Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER"
475 .It Li ACPI_UTILITIES
476 Utility ("ut") functions
478 Hardware access ("hw")
483 .It Li ACPI_NAMESPACE
484 Namespace evaluation ("ns")
487 .It Li ACPI_DISPATCHER
488 Internal representation of interpreter state ("ds")
490 Execute AML methods ("ex")
491 .It Li ACPI_RESOURCES
492 Resource parsing ("rs")
493 .It Li ACPI_CA_DEBUGGER
494 Debugger implementation ("db", "dm")
495 .It Li ACPI_OS_SERVICES
496 Usermode support routines ("os")
497 .It Li ACPI_CA_DISASSEMBLER
498 Disassembler implementation (unused)
499 .It Li ACPI_ALL_COMPONENTS
500 All the above ACPICA components
501 .It Li ACPI_AC_ADAPTER
504 Control-method battery driver
506 ACPI, ISA, and PCI bus drivers
508 Power and sleep button driver
510 Embedded controller driver
514 Platform-specific driver for hotkeys, LED, etc.
516 Power resource driver
517 .It Li ACPI_PROCESSOR
523 .It Li ACPI_ALL_DRIVERS
529 The supported levels are:
531 .Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE"
533 Initialization progress
534 .It Li ACPI_LV_DEBUG_OBJECT
537 General information and progress
538 .It Li ACPI_LV_REPAIR
539 Repair a common problem with predefined methods
540 .It Li ACPI_LV_ALL_EXCEPTIONS
541 All the previous levels
543 .It Li ACPI_LV_DISPATCH
546 .It Li ACPI_LV_OPREGION
547 .It Li ACPI_LV_BFIELD
548 .It Li ACPI_LV_TABLES
549 .It Li ACPI_LV_VALUES
550 .It Li ACPI_LV_OBJECTS
551 .It Li ACPI_LV_RESOURCES
552 .It Li ACPI_LV_USER_REQUESTS
553 .It Li ACPI_LV_PACKAGE
554 .It Li ACPI_LV_EVALUATION
555 .It Li ACPI_LV_VERBOSITY1
556 All the previous levels
557 .It Li ACPI_LV_ALLOCATIONS
558 .It Li ACPI_LV_FUNCTIONS
559 .It Li ACPI_LV_OPTIMIZATIONS
560 .It Li ACPI_LV_VERBOSITY2
561 All the previous levels
564 .Qq Li ACPI_LV_VERBOSITY2
566 .It Li ACPI_LV_THREADS
568 .It Li ACPI_LV_INTERRUPTS
569 .It Li ACPI_LV_VERBOSITY3
570 All the previous levels
571 .It Li ACPI_LV_AML_DISASSEMBLE
572 .It Li ACPI_LV_VERBOSE_INFO
573 .It Li ACPI_LV_FULL_TABLES
574 .It Li ACPI_LV_EVENTS
575 .It Li ACPI_LV_VERBOSE
577 .Qq Li ACPI_LV_VERBOSITY3
578 .It Li ACPI_LV_INIT_NAMES
579 Needs to be specified separately
581 Needs to be specified separately
584 Selection of the appropriate layer and level values is important
585 to avoid massive amounts of debugging output.
586 For example, the following configuration is a good way to gather initial
588 It enables debug output for both ACPICA and the
590 driver, printing basic information about errors, warnings, and progress.
591 .Bd -literal -offset indent
592 debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS"
593 debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS"
596 Debugging output by the ACPICA subsystem is prefixed with the
597 module name in lowercase, followed by a source line number.
600 code follows the same format, but
601 the module name is uppercased.
602 .Sh OVERRIDING YOUR BIOS BYTECODE
603 ACPI interprets bytecode named AML
604 (ACPI Machine Language)
605 provided by the BIOS vendor as a memory image at boot time.
606 Sometimes, the AML code contains a bug that does not appear when parsed
607 by the Microsoft implementation.
609 provides a way to override it with your own AML code to work around
610 or debug such problems.
611 Note that all AML in your DSDT and any SSDT tables is overridden.
613 In order to load your AML code, copy it to
614 .Pa /boot/kernel/acpi_dsdt.aml
615 and add the following line to
616 .Pa /boot/loader.conf .
617 .Bd -literal -offset indent
621 In order to prepare your AML code, you will need the
625 utilities and some ACPI knowledge.
632 .Xr acpi_panasonic 4 ,
635 .Xr acpi_thinkpad 4 ,
648 .%A "Hewlett-Packard Corporation"
649 .%A "Intel Corporation"
650 .%A "Microsoft Corporation"
651 .%A "Phoenix Technologies Ltd."
652 .%A "Toshiba Corporation"
653 .%D November 13, 2013
654 .%T "Advanced Configuration and Power Interface Specification"
655 .%U http://acpi.info/spec.htm
659 The ACPICA subsystem is developed and maintained by
660 Intel Architecture Labs.
662 The following people made notable contributions to the ACPI subsystem
666 .An Takanori Watanabe Aq Mt takawata@jp.FreeBSD.org ,
667 .An Mitsuru IWASAKI Aq Mt iwasaki@jp.FreeBSD.org ,
668 .An Munehiro Matsuda ,
670 the ACPI-jp mailing list at
671 .Aq Mt acpi-jp@jp.FreeBSD.org ,
672 and many other contributors.
674 This manual page was written by
675 .An Michael Smith Aq Mt msmith@FreeBSD.org .
677 Many BIOS versions have serious bugs that may cause system instability,
678 break suspend/resume, or prevent devices from operating properly due to
679 IRQ routing problems.
680 Upgrade your BIOS to the latest version available from the vendor before
681 deciding it is a problem with
686 .\"CPU idle power management drive conflicts with the local APIC (LAPIC)
688 .\"Disable APIC mode with
689 .\".Va hint.apic.0.disabled
694 .\"states if APIC mode is enabled.