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
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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 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.install_interface , hw.acpi.remove_interface
133 Install or remove OS interface(s) to control the return value of the
136 When an OS interface is specified in
137 .Va hw.acpi.install_interface ,
140 query for the interface returns it is
142 Conversely, when an OS interface is specified in
143 .Va hw.acpi.remove_interface ,
148 Multiple interfaces can be specified in a comma-separated list and
149 any leading white spaces will be ignored.
151 .Qq Li FreeBSD, Linux
152 is a valid list of two interfaces
156 .It Va hw.acpi.reset_video
157 Reset the video adapter from real mode during the resume path.
158 Some systems need this help, others have display problems if it is enabled.
159 Default is 0 (disabled).
160 .It Va hw.acpi.s4bios
161 Indicate whether the system supports
163 This means that the BIOS can handle all the functions of suspending the
165 Otherwise, the OS is responsible for suspending to disk
167 Most current systems do not support
169 .It Va hw.acpi.sleep_button_state
171 .Pq Li S1 Ns \[en] Ns Li S5
172 to enter when the sleep button is pressed.
173 This is usually a special function button on the keyboard.
177 .It Va hw.acpi.sleep_delay
178 Wait this number of seconds between preparing the system to suspend and
179 actually entering the suspend state.
181 .It Va hw.acpi.supported_sleep_state
183 .Pq Li S1 Ns \[en] Ns Li S5
184 supported by the BIOS.
185 .Bl -tag -width indent
187 Quick suspend to RAM.
188 The CPU enters a lower power state, but most peripherals are left running.
190 Lower power state than
192 but with the same basic characteristics.
193 Not supported by many systems.
196 Most devices are powered off, and the system stops running except for
200 All devices are powered off, and the system stops running.
201 When resuming, the system starts as if from a cold power on.
208 System shuts down cleanly and powers off.
210 .It Va hw.acpi.verbose
211 Enable verbose printing from the various ACPI subsystems.
214 Tunables can be set at the
216 prompt before booting the kernel or stored in
217 .Pa /boot/loader.conf .
218 Many of these tunables also have a matching
220 entry for access after boot.
221 .Bl -tag -width indent
222 .It Va acpi_dsdt_load
223 Enables loading of a custom ACPI DSDT.
224 .It Va acpi_dsdt_name
225 Name of the DSDT table to load, if loading is enabled.
228 .It Va debug.acpi.disabled
229 Selectively disables portions of ACPI that are enabled by default, for
231 .It Va debug.acpi.enabled
232 Selectively enables portions of ACPI that are disabled by default, for
234 .It Va debug.acpi.facs_addr32
235 Favor 32-bit FACS table addresses over the 64-bit addresses.
236 .It Va debug.acpi.fadt_addr32
237 Favor 32-bit FADT register addresses over the 64-bit addresses.
238 .It Va debug.acpi.ignore_xsdt
239 Ignore the XSDT, forcing the use of the RSDT.
240 .It Va debug.acpi.interpreter_slack
241 Enable less strict ACPI implementations.
242 Default is 1, ignore common BIOS mistakes.
243 .It Va debug.acpi.max_threads
244 Specify the number of task threads that are started on boot.
245 Limiting this to 1 may help work around various BIOSes that cannot
246 handle parallel requests.
247 The default value is 3.
248 .It Va debug.acpi.quirks
249 Override any automatic quirks completely.
250 .It Va debug.acpi.resume_beep
251 Beep the PC speaker on resume.
252 This can help diagnose suspend/resume problems.
253 Default is 0 (disabled).
254 .It Va hint.acpi.0.disabled
255 Set this to 1 to disable all of ACPI.
256 If ACPI has been disabled on your system due to a blacklist entry for your
257 BIOS, you can set this to 0 to re-enable ACPI for testing.
258 .It Va hw.acpi.ec.poll_timeout
259 Delay in milliseconds to wait for the EC to respond.
260 Try increasing this number if you get the error
261 .Qq Li AE_NO_HARDWARE_RESPONSE .
262 .It Va hw.acpi.host_mem_start
263 Override the assumed memory starting address for PCI host bridges.
264 .It Va hw.acpi.reset_video
265 Enables calling the VESA reset BIOS vector on the resume path.
266 This can fix some graphics cards that have problems such as LCD white-out
268 Default is 0 (disabled).
269 .It Va hw.acpi.auto_serialize_methods
270 Auto-serialization of control methods to proactively prevent problems with
271 ill-behaved reentrant control methods that create named ACPI objects.
272 Default is 1 (enabled).
273 .It Va hw.acpi.verbose
274 Turn on verbose debugging information about what ACPI is doing.
275 .It Va hw.pci.link.%s.%d.irq
276 Override the interrupt to use for this link and index.
277 This capability should be used carefully, and only if a device is not
282 is the name of the link (e.g., LNKA).
284 is the resource index when the link supports multiple IRQs.
285 Most PCI links only have one IRQ resource, so the below form should be used.
286 .It Va hw.pci.link.%s.irq
287 Override the interrupt to use.
288 This capability should be used carefully, and only if a device is not
293 is the name of the link (e.g., LNKA).
296 Since ACPI support on different platforms varies greatly, there are many
297 debugging and tuning options available.
299 For machines known not to work with
301 enabled, there is a BIOS blacklist.
302 Currently, the blacklist only controls whether
304 should be disabled or not.
305 In the future, it will have more granularity to control features (the
306 infrastructure for that is already there).
310 (for debugging purposes, etc.) on machines that are on the blacklist, set the
311 kernel environment variable
312 .Va hint.acpi.0.disabled
314 Before trying this, consider updating your BIOS to a more recent version that
315 may be compatible with ACPI.
319 driver completely, set the kernel environment variable
320 .Va hint.acpi.0.disabled
323 Some i386 machines totally fail to operate with some or all of ACPI disabled.
324 Other i386 machines fail with ACPI enabled.
325 Disabling all or part of ACPI on non-i386 platforms (i.e., platforms where
326 ACPI support is mandatory) may result in a non-functional system.
330 driver comprises a set of drivers, which may be selectively disabled
332 To disable a sub-driver, list it in the kernel
334 .Va debug.acpi.disabled .
335 Multiple entries can be listed, separated by a space.
337 ACPI sub-devices and features that can be disabled:
338 .Bl -tag -width ".Li sysresource"
340 Disable all ACPI features and devices.
346 Probes and attaches subdevices.
347 Disabling will avoid scanning the ACPI namespace entirely.
350 Attaches standard ACPI sub-drivers and devices enumerated in the
352 Disabling this has a similar effect to disabling
355 ACPI namespace will still be scanned.
358 Supports ACPI button devices (typically power and sleep buttons).
361 Control-method batteries device.
364 Supports CPU power-saving and speed-setting functions.
367 Supports CPU power-saving.
370 will also disable this device.
373 Supports CPU speed-setting.
376 will also disable this device.
379 Docking station device.
382 Supports the ACPI Embedded Controller interface, used to communicate
383 with embedded platform controllers.
386 Supports the High Precision Event Timer.
389 Supports an ISA bus bridge defined in the ACPI namespace,
390 typically as a child of a PCI bus.
393 Supports an ACPI laptop lid switch, which typically puts a
398 Quirks automatically disable ACPI functionality based on the XSDT table's
399 OEM vendor name and revision date.
402 Supports Host to PCI bridges.
405 Performs PCI interrupt routing.
408 Pseudo-devices containing resources which ACPI claims.
411 Supports system cooling and heat management.
414 Implements a timecounter using the ACPI fixed-frequency timer.
419 which may conflict with
426 .\"driver comprises a set of drivers,
427 .\"which may be selectively enabled in case of testing.
428 .\"To enable a sub-driver,
429 .\"list it in the kernel environment variable
430 .\".Va debug.acpi.enabled .
431 .\"Multiple entries can be listed,
432 .\"separated by a space.
434 .\"ACPI sub-devices and features that can be enabled:
435 .\".Bl -tag -width ".Li sysresource"
439 It is also possible to avoid portions of the ACPI namespace which
440 may be causing problems, by listing the full path of the root of
441 the region to be avoided in the kernel environment variable
442 .Va debug.acpi.avoid .
443 The object and all of its children will be ignored during the
444 bus/children scan of the namespace.
445 The ACPICA code will still know about the avoided region.
447 To enable debugging output,
449 must be compiled with
450 .Cd "options ACPI_DEBUG" .
451 Debugging output is separated between layers and levels, where a layer is
452 a component of the ACPI subsystem, and a level is a particular kind
455 Both layers and levels are specified as a whitespace-separated list of
456 tokens, with layers listed in
459 .Va debug.acpi.level .
461 The first set of layers is for ACPICA components, and the second is for
464 The ACPICA layer descriptions include the prefix for the files they
466 The supported layers are:
468 .Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER"
469 .It Li ACPI_UTILITIES
470 Utility ("ut") functions
472 Hardware access ("hw")
477 .It Li ACPI_NAMESPACE
478 Namespace evaluation ("ns")
481 .It Li ACPI_DISPATCHER
482 Internal representation of interpreter state ("ds")
484 Execute AML methods ("ex")
485 .It Li ACPI_RESOURCES
486 Resource parsing ("rs")
487 .It Li ACPI_CA_DEBUGGER
488 Debugger implementation ("db", "dm")
489 .It Li ACPI_OS_SERVICES
490 Usermode support routines ("os")
491 .It Li ACPI_CA_DISASSEMBLER
492 Disassembler implementation (unused)
493 .It Li ACPI_ALL_COMPONENTS
494 All the above ACPICA components
495 .It Li ACPI_AC_ADAPTER
498 Control-method battery driver
500 ACPI, ISA, and PCI bus drivers
502 Power and sleep button driver
504 Embedded controller driver
508 Platform-specific driver for hotkeys, LED, etc.
510 Power resource driver
511 .It Li ACPI_PROCESSOR
517 .It Li ACPI_ALL_DRIVERS
523 The supported levels are:
525 .Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE"
527 Initialization progress
528 .It Li ACPI_LV_DEBUG_OBJECT
531 General information and progress
532 .It Li ACPI_LV_REPAIR
533 Repair a common problem with predefined methods
534 .It Li ACPI_LV_ALL_EXCEPTIONS
535 All the previous levels
537 .It Li ACPI_LV_DISPATCH
540 .It Li ACPI_LV_OPREGION
541 .It Li ACPI_LV_BFIELD
542 .It Li ACPI_LV_TABLES
543 .It Li ACPI_LV_VALUES
544 .It Li ACPI_LV_OBJECTS
545 .It Li ACPI_LV_RESOURCES
546 .It Li ACPI_LV_USER_REQUESTS
547 .It Li ACPI_LV_PACKAGE
548 .It Li ACPI_LV_VERBOSITY1
549 All the previous levels
550 .It Li ACPI_LV_ALLOCATIONS
551 .It Li ACPI_LV_FUNCTIONS
552 .It Li ACPI_LV_OPTIMIZATIONS
553 .It Li ACPI_LV_VERBOSITY2
554 All the previous levels
557 .Qq Li ACPI_LV_VERBOSITY2
559 .It Li ACPI_LV_THREADS
561 .It Li ACPI_LV_INTERRUPTS
562 .It Li ACPI_LV_VERBOSITY3
563 All the previous levels
564 .It Li ACPI_LV_AML_DISASSEMBLE
565 .It Li ACPI_LV_VERBOSE_INFO
566 .It Li ACPI_LV_FULL_TABLES
567 .It Li ACPI_LV_EVENTS
568 .It Li ACPI_LV_VERBOSE
570 .Qq Li ACPI_LV_VERBOSITY3
571 .It Li ACPI_LV_INIT_NAMES
572 Needs to be specified separately
574 Needs to be specified separately
577 Selection of the appropriate layer and level values is important
578 to avoid massive amounts of debugging output.
579 For example, the following configuration is a good way to gather initial
581 It enables debug output for both ACPICA and the
583 driver, printing basic information about errors, warnings, and progress.
584 .Bd -literal -offset indent
585 debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS"
586 debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS"
589 Debugging output by the ACPICA subsystem is prefixed with the
590 module name in lowercase, followed by a source line number.
593 code follows the same format, but
594 the module name is uppercased.
595 .Sh OVERRIDING YOUR BIOS BYTECODE
596 ACPI interprets bytecode named AML
597 (ACPI Machine Language)
598 provided by the BIOS vendor as a memory image at boot time.
599 Sometimes, the AML code contains a bug that does not appear when parsed
600 by the Microsoft implementation.
602 provides a way to override it with your own AML code to work around
603 or debug such problems.
604 Note that all AML in your DSDT and any SSDT tables is overridden.
606 In order to load your AML code, copy it to
607 .Pa /boot/kernel/acpi_dsdt.aml
608 and add the following line to
609 .Pa /boot/loader.conf .
610 .Bd -literal -offset indent
614 In order to prepare your AML code, you will need the
618 utilities and some ACPI knowledge.
620 .\"ACPI is only found and supported on i386 and x86_64.
627 .Xr acpi_panasonic 4 ,
630 .Xr acpi_thinkpad 4 ,
644 .%A "Hewlett-Packard Corporation"
645 .%A "Intel Corporation"
646 .%A "Microsoft Corporation"
647 .%A "Phoenix Technologies Ltd."
648 .%A "Toshiba Corporation"
649 .%D November 13, 2013
650 .%T "Advanced Configuration and Power Interface Specification"
651 .%O http://acpi.info/spec.htm
655 The ACPICA subsystem is developed and maintained by
656 Intel Architecture Labs.
658 The following people made notable contributions to the ACPI subsystem
662 .An Takanori Watanabe Aq Mt takawata@jp.FreeBSD.org ,
663 .An Mitsuru IWASAKI Aq Mt iwasaki@jp.FreeBSD.org ,
664 .An Munehiro Matsuda ,
666 the ACPI-jp mailing list at
667 .Aq Mt acpi-jp@jp.FreeBSD.org ,
668 and many other contributors.
670 This manual page was written by
671 .An Michael Smith Aq Mt msmith@FreeBSD.org .
673 Many BIOS versions have serious bugs that may cause system instability,
674 break suspend/resume, or prevent devices from operating properly due to
675 IRQ routing problems.
676 Upgrade your BIOS to the latest version available from the vendor before
677 deciding it is a problem with
682 .\"CPU idle power management drive conflicts with the local APIC (LAPIC)
684 .\"Disable APIC mode with
685 .\".Va hint.apic.0.disabled
690 .\"states if APIC mode is enabled.