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.
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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)
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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 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 Supports the ACPI Embedded Controller interface, used to communicate
347 with embedded platform controllers.
350 Supports an ISA bus bridge defined in the ACPI namespace,
351 typically as a child of a PCI bus.
354 Supports an ACPI laptop lid switch, which typically puts a
359 Quirks automatically disable ACPI functionality based on the XSDT table's
360 OEM vendor name and revision date.
363 Supports Host to PCI bridges.
366 Performs PCI interrupt routing.
369 Pseudo-devices containing resources which ACPI claims.
372 Supports system cooling and heat management.
375 Implements a timecounter using the ACPI fixed-frequency timer.
378 Supports the High Precision Event Timer.
383 which may conflict with
390 .\"driver comprises a set of drivers,
391 .\"which may be selectively enabled in case of testing.
392 .\"To enable a sub-driver,
393 .\"list it in the kernel environment variable
394 .\".Va debug.acpi.enabled .
395 .\"Multiple entries can be listed,
396 .\"separated by a space.
398 .\"ACPI sub-devices and features that can be enabled:
399 .\".Bl -tag -width ".Li sysresource"
403 It is also possible to avoid portions of the ACPI namespace which
404 may be causing problems, by listing the full path of the root of
405 the region to be avoided in the kernel environment variable
406 .Va debug.acpi.avoid .
407 The object and all of its children will be ignored during the
408 bus/children scan of the namespace.
409 The ACPICA code will still know about the avoided region.
411 To enable debugging output,
413 must be compiled with
414 .Cd "options ACPI_DEBUG" .
415 Debugging output is separated between layers and levels, where a layer is
416 a component of the ACPI subsystem, and a level is a particular kind
419 Both layers and levels are specified as a whitespace-separated list of
420 tokens, with layers listed in
423 .Va debug.acpi.level .
425 The first set of layers is for ACPICA components, and the second is for
428 The ACPICA layer descriptions include the prefix for the files they
430 The supported layers are:
432 .Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER"
433 .It Li ACPI_UTILITIES
434 Utility ("ut") functions
436 Hardware access ("hw")
441 .It Li ACPI_NAMESPACE
442 Namespace evaluation ("ns")
445 .It Li ACPI_DISPATCHER
446 Internal representation of interpreter state ("ds")
448 Execute AML methods ("ex")
449 .It Li ACPI_RESOURCES
450 Resource parsing ("rs")
451 .It Li ACPI_CA_DEBUGGER
452 Debugger implementation ("db", "dm")
453 .It Li ACPI_OS_SERVICES
454 Usermode support routines ("os")
455 .It Li ACPI_CA_DISASSEMBLER
456 Disassembler implementation (unused)
457 .It Li ACPI_ALL_COMPONENTS
458 All the above ACPICA components
459 .It Li ACPI_AC_ADAPTER
462 Control-method battery driver
464 ACPI, ISA, and PCI bus drivers
466 Power and sleep button driver
468 Embedded controller driver
472 Platform-specific driver for hotkeys, LED, etc.
474 Power resource driver
475 .It Li ACPI_PROCESSOR
481 .It Li ACPI_ALL_DRIVERS
487 The supported levels are:
489 .Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE"
491 Initialization progress
492 .It Li ACPI_LV_DEBUG_OBJECT
495 General information and progress
496 .It Li ACPI_LV_REPAIR
497 Repair a common problem with predefined methods
498 .It Li ACPI_LV_ALL_EXCEPTIONS
499 All the previous levels
501 .It Li ACPI_LV_DISPATCH
504 .It Li ACPI_LV_OPREGION
505 .It Li ACPI_LV_BFIELD
506 .It Li ACPI_LV_TABLES
507 .It Li ACPI_LV_VALUES
508 .It Li ACPI_LV_OBJECTS
509 .It Li ACPI_LV_RESOURCES
510 .It Li ACPI_LV_USER_REQUESTS
511 .It Li ACPI_LV_PACKAGE
512 .It Li ACPI_LV_VERBOSITY1
513 All the previous levels
514 .It Li ACPI_LV_ALLOCATIONS
515 .It Li ACPI_LV_FUNCTIONS
516 .It Li ACPI_LV_OPTIMIZATIONS
517 .It Li ACPI_LV_VERBOSITY2
518 All the previous levels
521 .Qq Li ACPI_LV_VERBOSITY2
523 .It Li ACPI_LV_THREADS
525 .It Li ACPI_LV_INTERRUPTS
526 .It Li ACPI_LV_VERBOSITY3
527 All the previous levels
528 .It Li ACPI_LV_AML_DISASSEMBLE
529 .It Li ACPI_LV_VERBOSE_INFO
530 .It Li ACPI_LV_FULL_TABLES
531 .It Li ACPI_LV_EVENTS
532 .It Li ACPI_LV_VERBOSE
534 .Qq Li ACPI_LV_VERBOSITY3
535 .It Li ACPI_LV_INIT_NAMES
536 Needs to be specified separately
538 Needs to be specified separately
541 Selection of the appropriate layer and level values is important
542 to avoid massive amounts of debugging output.
543 For example, the following configuration is a good way to gather initial
545 It enables debug output for both ACPICA and the
547 driver, printing basic information about errors, warnings, and progress.
548 .Bd -literal -offset indent
549 debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS"
550 debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS"
553 Debugging output by the ACPICA subsystem is prefixed with the
554 module name in lowercase, followed by a source line number.
557 code follows the same format, but
558 the module name is uppercased.
559 .Sh OVERRIDING YOUR BIOS BYTECODE
560 ACPI interprets bytecode named AML
561 (ACPI Machine Language)
562 provided by the BIOS vendor as a memory image at boot time.
563 Sometimes, the AML code contains a bug that does not appear when parsed
564 by the Microsoft implementation.
566 provides a way to override it with your own AML code to work around
567 or debug such problems.
568 Note that all AML in your DSDT and any SSDT tables is overridden.
570 In order to load your AML code, copy it to
571 .Pa /boot/kernel/acpi_dsdt.aml
572 and add the following line to
573 .Pa /boot/loader.conf .
574 .Bd -literal -offset indent
578 In order to prepare your AML code, you will need the
582 utilities and some ACPI knowledge.
584 .\"ACPI is only found and supported on i386 and x86_64.
590 .Xr acpi_panasonic 4 ,
593 .Xr acpi_thinkpad 4 ,
607 .%A "Hewlett-Packard Corporation"
608 .%A "Intel Corporation"
609 .%A "Microsoft Corporation"
610 .%A "Phoenix Technologies Ltd."
611 .%A "Toshiba Corporation"
612 .%D November 13, 2013
613 .%T "Advanced Configuration and Power Interface Specification"
614 .%O http://acpi.info/spec.htm
618 The ACPICA subsystem is developed and maintained by
619 Intel Architecture Labs.
621 The following people made notable contributions to the ACPI subsystem
625 .An Takanori Watanabe Aq Mt takawata@jp.FreeBSD.org ,
626 .An Mitsuru IWASAKI Aq Mt iwasaki@jp.FreeBSD.org ,
627 .An Munehiro Matsuda ,
629 the ACPI-jp mailing list at
630 .Aq Mt acpi-jp@jp.FreeBSD.org ,
631 and many other contributors.
633 This manual page was written by
634 .An Michael Smith Aq Mt msmith@FreeBSD.org .
636 Many BIOS versions have serious bugs that may cause system instability,
637 break suspend/resume, or prevent devices from operating properly due to
638 IRQ routing problems.
639 Upgrade your BIOS to the latest version available from the vendor before
640 deciding it is a problem with
645 .\"CPU idle power management drive conflicts with the local APIC (LAPIC)
647 .\"Disable APIC mode with
648 .\".Va hint.apic.0.disabled
653 .\"states if APIC mode is enabled.