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
8 .\" 1. Redistributions of source code must retain the above copyright
9 .\" notice, this list of conditions and the following disclaimer.
10 .\" 2. Redistributions in binary form must reproduce the above copyright
11 .\" notice, this list of conditions and the following disclaimer in the
12 .\" documentation and/or other materials provided with the distribution.
14 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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)
21 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 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 If the default settings are not optimal, the following sysctls can be
61 used to modify or monitor
64 .Bl -tag -width indent
65 .It Va debug.acpi.enable_debug_objects
66 Enable dumping Debug objects without
67 .Cd "options ACPI_DEBUG" .
68 Default is 0, ignore Debug objects.
70 AC line state (1 means online, 0 means on battery power).
71 .It Va hw.acpi.cpu.cx_usage
72 Debugging information listing the percent of total usage for each sleep state.
73 The values are reset when
74 .Va hw.acpi.cpu.cx_lowest
76 .It Va hw.acpi.cpu.cx_lowest
77 Lowest Cx state to use for idling the CPU.
78 A scheduling algorithm will select states between
81 as system load dictates.
82 To enable ACPI CPU idling control,
83 .Va machdep.cpu_idle_hlt
84 must be set to 2 (the default value).
85 .It Va hw.acpi.cpu.cx_supported
86 List of supported CPU idle states and their transition latency
88 Each state has a type (e.g.,
91 is equivalent to the ia32
96 sleep with the same semantics, and
98 provides the deepest sleep
99 but additionally requires bus mastering to be disabled.
102 provide even more power savings with the same
106 Deeper sleeps provide more power savings but increased transition
107 latency when an interrupt occurs.
108 .It Va hw.acpi.disable_on_reboot
109 Disable ACPI during the reboot process.
110 Most systems reboot fine with ACPI still enabled, but some require
111 exiting to legacy mode first.
112 Default is 0, leave ACPI enabled.
113 .It Va hw.acpi.handle_reboot
114 Use the ACPI Reset Register capability to reboot the system.
115 Default is 0, use legacy reboot support.
116 Some newer systems require use of this register, while some only work
117 with legacy rebooting support.
118 .It Va hw.acpi.lid_switch_state
120 .Pq Li S1 Ns \[en] Ns Li S5
121 to enter when the lid switch (i.e., a notebook screen) is closed.
125 .It Va hw.acpi.power_button_state
127 .Pq Li S1 Ns \[en] Ns Li S5
128 to enter when the power button is pressed.
132 .It Va hw.acpi.reset_video
133 Reset the video adapter from real mode during the resume path.
134 Some systems need this help, others have display problems if it is enabled.
135 Default is 0 (disabled).
136 .It Va hw.acpi.s4bios
137 Indicate whether the system supports
139 This means that the BIOS can handle all the functions of suspending the
141 Otherwise, the OS is responsible for suspending to disk
143 Most current systems do not support
145 .It Va hw.acpi.sleep_button_state
147 .Pq Li S1 Ns \[en] Ns Li S5
148 to enter when the sleep button is pressed.
149 This is usually a special function button on the keyboard.
153 .It Va hw.acpi.sleep_delay
154 Wait this number of seconds between preparing the system to suspend and
155 actually entering the suspend state.
157 .It Va hw.acpi.supported_sleep_state
159 .Pq Li S1 Ns \[en] Ns Li S5
160 supported by the BIOS.
161 .Bl -tag -width indent
163 Quick suspend to RAM.
164 The CPU enters a lower power state, but most peripherals are left running.
166 Lower power state than
168 but with the same basic characteristics.
169 Not supported by many systems.
172 Most devices are powered off, and the system stops running except for
176 All devices are powered off, and the system stops running.
177 When resuming, the system starts as if from a cold power on.
184 System shuts down cleanly and powers off.
186 .It Va hw.acpi.verbose
187 Enable verbose printing from the various ACPI subsystems.
190 Tunables can be set at the
192 prompt before booting the kernel or stored in
193 .Pa /boot/loader.conf .
194 Many of these tunables also have a matching
196 entry for access after boot.
197 .Bl -tag -width indent
198 .It Va acpi_dsdt_load
199 Enables loading of a custom ACPI DSDT.
200 .It Va acpi_dsdt_name
201 Name of the DSDT table to load, if loading is enabled.
204 .It Va debug.acpi.disabled
205 Selectively disables portions of ACPI that are enabled by default, for
207 .It Va debug.acpi.enabled
208 Selectively enables portions of ACPI that are disabled by default, for
210 .It Va debug.acpi.max_threads
211 Specify the number of task threads that are started on boot.
212 Limiting this to 1 may help work around various BIOSes that cannot
213 handle parallel requests.
214 The default value is 3.
215 .It Va debug.acpi.quirks
216 Override any automatic quirks completely.
217 .It Va debug.acpi.resume_beep
218 Beep the PC speaker on resume.
219 This can help diagnose suspend/resume problems.
220 Default is 0 (disabled).
221 .It Va hint.acpi.0.disabled
222 Set this to 1 to disable all of ACPI.
223 If ACPI has been disabled on your system due to a blacklist entry for your
224 BIOS, you can set this to 0 to re-enable ACPI for testing.
225 .It Va hw.acpi.ec.poll_timeout
226 Delay in milliseconds to wait for the EC to respond.
227 Try increasing this number if you get the error
228 .Qq Li AE_NO_HARDWARE_RESPONSE .
229 .It Va hw.acpi.host_mem_start
230 Override the assumed memory starting address for PCI host bridges.
231 .It Va hw.acpi.reset_video
232 Enables calling the VESA reset BIOS vector on the resume path.
233 This can fix some graphics cards that have problems such as LCD white-out
235 Default is 0 (disabled).
236 .It Va hw.acpi.auto_serialize_methods
237 Auto-serialization of control methods to proactively prevent problems with
238 ill-behaved reentrant control methods that create named ACPI objects.
239 Default is 1 (enabled).
240 .It Va hw.acpi.verbose
241 Turn on verbose debugging information about what ACPI is doing.
242 .It Va hw.pci.link.%s.%d.irq
243 Override the interrupt to use for this link and index.
244 This capability should be used carefully, and only if a device is not
249 is the name of the link (e.g., LNKA).
251 is the resource index when the link supports multiple IRQs.
252 Most PCI links only have one IRQ resource, so the below form should be used.
253 .It Va hw.pci.link.%s.irq
254 Override the interrupt to use.
255 This capability should be used carefully, and only if a device is not
260 is the name of the link (e.g., LNKA).
263 Since ACPI support on different platforms varies greatly, there are many
264 debugging and tuning options available.
266 For machines known not to work with
268 enabled, there is a BIOS blacklist.
269 Currently, the blacklist only controls whether
271 should be disabled or not.
272 In the future, it will have more granularity to control features (the
273 infrastructure for that is already there).
277 (for debugging purposes, etc.) on machines that are on the blacklist, set the
278 kernel environment variable
279 .Va hint.acpi.0.disabled
281 Before trying this, consider updating your BIOS to a more recent version that
282 may be compatible with ACPI.
286 driver completely, set the kernel environment variable
287 .Va hint.acpi.0.disabled
290 Some i386 machines totally fail to operate with some or all of ACPI disabled.
291 Other i386 machines fail with ACPI enabled.
292 Disabling all or part of ACPI on non-i386 platforms (i.e., platforms where
293 ACPI support is mandatory) may result in a non-functional system.
297 driver comprises a set of drivers, which may be selectively disabled
299 To disable a sub-driver, list it in the kernel
301 .Va debug.acpi.disabled .
302 Multiple entries can be listed, separated by a space.
304 ACPI sub-devices and features that can be disabled:
305 .Bl -tag -width ".Li sysresource"
307 Disable all ACPI features and devices.
313 Probes and attaches subdevices.
314 Disabling will avoid scanning the ACPI namespace entirely.
317 Attaches standard ACPI sub-drivers and devices enumerated in the
319 Disabling this has a similar effect to disabling
322 ACPI namespace will still be scanned.
325 Supports ACPI button devices (typically power and sleep buttons).
328 Control-method batteries device.
331 Supports CPU power-saving and speed-setting functions.
334 Supports CPU power-saving.
337 will also disable this device.
340 Supports CPU speed-setting.
343 will also disable this device.
346 Docking station device.
349 Supports the ACPI Embedded Controller interface, used to communicate
350 with embedded platform controllers.
353 Supports the High Precision Event Timer.
356 Supports an ISA bus bridge defined in the ACPI namespace,
357 typically as a child of a PCI bus.
360 Supports an ACPI laptop lid switch, which typically puts a
365 Quirks automatically disable ACPI functionality based on the XSDT table's
366 OEM vendor name and revision date.
369 Supports Host to PCI bridges.
372 Performs PCI interrupt routing.
375 Pseudo-devices containing resources which ACPI claims.
378 Supports system cooling and heat management.
381 Implements a timecounter using the ACPI fixed-frequency timer.
386 which may conflict with
393 .\"driver comprises a set of drivers,
394 .\"which may be selectively enabled in case of testing.
395 .\"To enable a sub-driver,
396 .\"list it in the kernel environment variable
397 .\".Va debug.acpi.enabled .
398 .\"Multiple entries can be listed,
399 .\"separated by a space.
401 .\"ACPI sub-devices and features that can be enabled:
402 .\".Bl -tag -width ".Li sysresource"
406 It is also possible to avoid portions of the ACPI namespace which
407 may be causing problems, by listing the full path of the root of
408 the region to be avoided in the kernel environment variable
409 .Va debug.acpi.avoid .
410 The object and all of its children will be ignored during the
411 bus/children scan of the namespace.
412 The ACPICA code will still know about the avoided region.
414 To enable debugging output,
416 must be compiled with
417 .Cd "options ACPI_DEBUG" .
418 Debugging output is separated between layers and levels, where a layer is
419 a component of the ACPI subsystem, and a level is a particular kind
422 Both layers and levels are specified as a whitespace-separated list of
423 tokens, with layers listed in
426 .Va debug.acpi.level .
428 The first set of layers is for ACPICA components, and the second is for
431 The ACPICA layer descriptions include the prefix for the files they
433 The supported layers are:
435 .Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER"
436 .It Li ACPI_UTILITIES
437 Utility ("ut") functions
439 Hardware access ("hw")
444 .It Li ACPI_NAMESPACE
445 Namespace evaluation ("ns")
448 .It Li ACPI_DISPATCHER
449 Internal representation of interpreter state ("ds")
451 Execute AML methods ("ex")
452 .It Li ACPI_RESOURCES
453 Resource parsing ("rs")
454 .It Li ACPI_CA_DEBUGGER
455 Debugger implementation ("db", "dm")
456 .It Li ACPI_OS_SERVICES
457 Usermode support routines ("os")
458 .It Li ACPI_CA_DISASSEMBLER
459 Disassembler implementation (unused)
460 .It Li ACPI_ALL_COMPONENTS
461 All the above ACPICA components
462 .It Li ACPI_AC_ADAPTER
465 Control-method battery driver
467 ACPI, ISA, and PCI bus drivers
469 Power and sleep button driver
471 Embedded controller driver
475 Platform-specific driver for hotkeys, LED, etc.
477 Power resource driver
478 .It Li ACPI_PROCESSOR
484 .It Li ACPI_ALL_DRIVERS
490 The supported levels are:
492 .Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE"
494 Initialization progress
495 .It Li ACPI_LV_DEBUG_OBJECT
498 General information and progress
499 .It Li ACPI_LV_REPAIR
500 Repair a common problem with predefined methods
501 .It Li ACPI_LV_ALL_EXCEPTIONS
502 All the previous levels
504 .It Li ACPI_LV_DISPATCH
507 .It Li ACPI_LV_OPREGION
508 .It Li ACPI_LV_BFIELD
509 .It Li ACPI_LV_TABLES
510 .It Li ACPI_LV_VALUES
511 .It Li ACPI_LV_OBJECTS
512 .It Li ACPI_LV_RESOURCES
513 .It Li ACPI_LV_USER_REQUESTS
514 .It Li ACPI_LV_PACKAGE
515 .It Li ACPI_LV_VERBOSITY1
516 All the previous levels
517 .It Li ACPI_LV_ALLOCATIONS
518 .It Li ACPI_LV_FUNCTIONS
519 .It Li ACPI_LV_OPTIMIZATIONS
520 .It Li ACPI_LV_VERBOSITY2
521 All the previous levels
524 .Qq Li ACPI_LV_VERBOSITY2
526 .It Li ACPI_LV_THREADS
528 .It Li ACPI_LV_INTERRUPTS
529 .It Li ACPI_LV_VERBOSITY3
530 All the previous levels
531 .It Li ACPI_LV_AML_DISASSEMBLE
532 .It Li ACPI_LV_VERBOSE_INFO
533 .It Li ACPI_LV_FULL_TABLES
534 .It Li ACPI_LV_EVENTS
535 .It Li ACPI_LV_VERBOSE
537 .Qq Li ACPI_LV_VERBOSITY3
538 .It Li ACPI_LV_INIT_NAMES
539 Needs to be specified separately
541 Needs to be specified separately
544 Selection of the appropriate layer and level values is important
545 to avoid massive amounts of debugging output.
546 For example, the following configuration is a good way to gather initial
548 It enables debug output for both ACPICA and the
550 driver, printing basic information about errors, warnings, and progress.
551 .Bd -literal -offset indent
552 debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS"
553 debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS"
556 Debugging output by the ACPICA subsystem is prefixed with the
557 module name in lowercase, followed by a source line number.
560 code follows the same format, but
561 the module name is uppercased.
562 .Sh OVERRIDING YOUR BIOS BYTECODE
563 ACPI interprets bytecode named AML
564 (ACPI Machine Language)
565 provided by the BIOS vendor as a memory image at boot time.
566 Sometimes, the AML code contains a bug that does not appear when parsed
567 by the Microsoft implementation.
569 provides a way to override it with your own AML code to work around
570 or debug such problems.
571 Note that all AML in your DSDT and any SSDT tables is overridden.
573 In order to load your AML code, copy it to
574 .Pa /boot/kernel/acpi_dsdt.aml
575 and add the following line to
576 .Pa /boot/loader.conf .
577 .Bd -literal -offset indent
581 In order to prepare your AML code, you will need the
585 utilities and some ACPI knowledge.
587 .\"ACPI is only found and supported on i386 and x86_64.
594 .Xr acpi_panasonic 4 ,
597 .Xr acpi_thinkpad 4 ,
611 .%A "Hewlett-Packard Corporation"
612 .%A "Intel Corporation"
613 .%A "Microsoft Corporation"
614 .%A "Phoenix Technologies Ltd."
615 .%A "Toshiba Corporation"
616 .%D November 13, 2013
617 .%T "Advanced Configuration and Power Interface Specification"
618 .%O http://acpi.info/spec.htm
622 The ACPICA subsystem is developed and maintained by
623 Intel Architecture Labs.
625 The following people made notable contributions to the ACPI subsystem
629 .An Takanori Watanabe Aq Mt takawata@jp.FreeBSD.org ,
630 .An Mitsuru IWASAKI Aq Mt iwasaki@jp.FreeBSD.org ,
631 .An Munehiro Matsuda ,
633 the ACPI-jp mailing list at
634 .Aq Mt acpi-jp@jp.FreeBSD.org ,
635 and many other contributors.
637 This manual page was written by
638 .An Michael Smith Aq Mt msmith@FreeBSD.org .
640 Many BIOS versions have serious bugs that may cause system instability,
641 break suspend/resume, or prevent devices from operating properly due to
642 IRQ routing problems.
643 Upgrade your BIOS to the latest version available from the vendor before
644 deciding it is a problem with
649 .\"CPU idle power management drive conflicts with the local APIC (LAPIC)
651 .\"Disable APIC mode with
652 .\".Va hint.apic.0.disabled
657 .\"states if APIC mode is enabled.