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.fadt_addr32
235 Favor 32-bit FADT register addresses over the 64-bit addresses.
236 .It Va debug.acpi.ignore_xsdt
237 Ignore the XSDT, forcing the use of the RSDT.
238 .It Va debug.acpi.interpreter_slack
239 Enable less strict ACPI implementations.
240 Default is 1, ignore common BIOS mistakes.
241 .It Va debug.acpi.max_threads
242 Specify the number of task threads that are started on boot.
243 Limiting this to 1 may help work around various BIOSes that cannot
244 handle parallel requests.
245 The default value is 3.
246 .It Va debug.acpi.quirks
247 Override any automatic quirks completely.
248 .It Va debug.acpi.resume_beep
249 Beep the PC speaker on resume.
250 This can help diagnose suspend/resume problems.
251 Default is 0 (disabled).
252 .It Va hint.acpi.0.disabled
253 Set this to 1 to disable all of ACPI.
254 If ACPI has been disabled on your system due to a blacklist entry for your
255 BIOS, you can set this to 0 to re-enable ACPI for testing.
256 .It Va hw.acpi.ec.poll_timeout
257 Delay in milliseconds to wait for the EC to respond.
258 Try increasing this number if you get the error
259 .Qq Li AE_NO_HARDWARE_RESPONSE .
260 .It Va hw.acpi.host_mem_start
261 Override the assumed memory starting address for PCI host bridges.
262 .It Va hw.acpi.reset_video
263 Enables calling the VESA reset BIOS vector on the resume path.
264 This can fix some graphics cards that have problems such as LCD white-out
266 Default is 0 (disabled).
267 .It Va hw.acpi.auto_serialize_methods
268 Auto-serialization of control methods to proactively prevent problems with
269 ill-behaved reentrant control methods that create named ACPI objects.
270 Default is 1 (enabled).
271 .It Va hw.acpi.verbose
272 Turn on verbose debugging information about what ACPI is doing.
273 .It Va hw.pci.link.%s.%d.irq
274 Override the interrupt to use for this link and index.
275 This capability should be used carefully, and only if a device is not
280 is the name of the link (e.g., LNKA).
282 is the resource index when the link supports multiple IRQs.
283 Most PCI links only have one IRQ resource, so the below form should be used.
284 .It Va hw.pci.link.%s.irq
285 Override the interrupt to use.
286 This capability should be used carefully, and only if a device is not
291 is the name of the link (e.g., LNKA).
294 Since ACPI support on different platforms varies greatly, there are many
295 debugging and tuning options available.
297 For machines known not to work with
299 enabled, there is a BIOS blacklist.
300 Currently, the blacklist only controls whether
302 should be disabled or not.
303 In the future, it will have more granularity to control features (the
304 infrastructure for that is already there).
308 (for debugging purposes, etc.) on machines that are on the blacklist, set the
309 kernel environment variable
310 .Va hint.acpi.0.disabled
312 Before trying this, consider updating your BIOS to a more recent version that
313 may be compatible with ACPI.
317 driver completely, set the kernel environment variable
318 .Va hint.acpi.0.disabled
321 Some i386 machines totally fail to operate with some or all of ACPI disabled.
322 Other i386 machines fail with ACPI enabled.
323 Disabling all or part of ACPI on non-i386 platforms (i.e., platforms where
324 ACPI support is mandatory) may result in a non-functional system.
328 driver comprises a set of drivers, which may be selectively disabled
330 To disable a sub-driver, list it in the kernel
332 .Va debug.acpi.disabled .
333 Multiple entries can be listed, separated by a space.
335 ACPI sub-devices and features that can be disabled:
336 .Bl -tag -width ".Li sysresource"
338 Disable all ACPI features and devices.
344 Probes and attaches subdevices.
345 Disabling will avoid scanning the ACPI namespace entirely.
348 Attaches standard ACPI sub-drivers and devices enumerated in the
350 Disabling this has a similar effect to disabling
353 ACPI namespace will still be scanned.
356 Supports ACPI button devices (typically power and sleep buttons).
359 Control-method batteries device.
362 Supports CPU power-saving and speed-setting functions.
365 Supports CPU power-saving.
368 will also disable this device.
371 Supports CPU speed-setting.
374 will also disable this device.
377 Docking station device.
380 Supports the ACPI Embedded Controller interface, used to communicate
381 with embedded platform controllers.
384 Supports the High Precision Event Timer.
387 Supports an ISA bus bridge defined in the ACPI namespace,
388 typically as a child of a PCI bus.
391 Supports an ACPI laptop lid switch, which typically puts a
396 Quirks automatically disable ACPI functionality based on the XSDT table's
397 OEM vendor name and revision date.
400 Supports Host to PCI bridges.
403 Performs PCI interrupt routing.
406 Pseudo-devices containing resources which ACPI claims.
409 Supports system cooling and heat management.
412 Implements a timecounter using the ACPI fixed-frequency timer.
417 which may conflict with
424 .\"driver comprises a set of drivers,
425 .\"which may be selectively enabled in case of testing.
426 .\"To enable a sub-driver,
427 .\"list it in the kernel environment variable
428 .\".Va debug.acpi.enabled .
429 .\"Multiple entries can be listed,
430 .\"separated by a space.
432 .\"ACPI sub-devices and features that can be enabled:
433 .\".Bl -tag -width ".Li sysresource"
437 It is also possible to avoid portions of the ACPI namespace which
438 may be causing problems, by listing the full path of the root of
439 the region to be avoided in the kernel environment variable
440 .Va debug.acpi.avoid .
441 The object and all of its children will be ignored during the
442 bus/children scan of the namespace.
443 The ACPICA code will still know about the avoided region.
445 To enable debugging output,
447 must be compiled with
448 .Cd "options ACPI_DEBUG" .
449 Debugging output is separated between layers and levels, where a layer is
450 a component of the ACPI subsystem, and a level is a particular kind
453 Both layers and levels are specified as a whitespace-separated list of
454 tokens, with layers listed in
457 .Va debug.acpi.level .
459 The first set of layers is for ACPICA components, and the second is for
462 The ACPICA layer descriptions include the prefix for the files they
464 The supported layers are:
466 .Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER"
467 .It Li ACPI_UTILITIES
468 Utility ("ut") functions
470 Hardware access ("hw")
475 .It Li ACPI_NAMESPACE
476 Namespace evaluation ("ns")
479 .It Li ACPI_DISPATCHER
480 Internal representation of interpreter state ("ds")
482 Execute AML methods ("ex")
483 .It Li ACPI_RESOURCES
484 Resource parsing ("rs")
485 .It Li ACPI_CA_DEBUGGER
486 Debugger implementation ("db", "dm")
487 .It Li ACPI_OS_SERVICES
488 Usermode support routines ("os")
489 .It Li ACPI_CA_DISASSEMBLER
490 Disassembler implementation (unused)
491 .It Li ACPI_ALL_COMPONENTS
492 All the above ACPICA components
493 .It Li ACPI_AC_ADAPTER
496 Control-method battery driver
498 ACPI, ISA, and PCI bus drivers
500 Power and sleep button driver
502 Embedded controller driver
506 Platform-specific driver for hotkeys, LED, etc.
508 Power resource driver
509 .It Li ACPI_PROCESSOR
515 .It Li ACPI_ALL_DRIVERS
521 The supported levels are:
523 .Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE"
525 Initialization progress
526 .It Li ACPI_LV_DEBUG_OBJECT
529 General information and progress
530 .It Li ACPI_LV_REPAIR
531 Repair a common problem with predefined methods
532 .It Li ACPI_LV_ALL_EXCEPTIONS
533 All the previous levels
535 .It Li ACPI_LV_DISPATCH
538 .It Li ACPI_LV_OPREGION
539 .It Li ACPI_LV_BFIELD
540 .It Li ACPI_LV_TABLES
541 .It Li ACPI_LV_VALUES
542 .It Li ACPI_LV_OBJECTS
543 .It Li ACPI_LV_RESOURCES
544 .It Li ACPI_LV_USER_REQUESTS
545 .It Li ACPI_LV_PACKAGE
546 .It Li ACPI_LV_VERBOSITY1
547 All the previous levels
548 .It Li ACPI_LV_ALLOCATIONS
549 .It Li ACPI_LV_FUNCTIONS
550 .It Li ACPI_LV_OPTIMIZATIONS
551 .It Li ACPI_LV_VERBOSITY2
552 All the previous levels
555 .Qq Li ACPI_LV_VERBOSITY2
557 .It Li ACPI_LV_THREADS
559 .It Li ACPI_LV_INTERRUPTS
560 .It Li ACPI_LV_VERBOSITY3
561 All the previous levels
562 .It Li ACPI_LV_AML_DISASSEMBLE
563 .It Li ACPI_LV_VERBOSE_INFO
564 .It Li ACPI_LV_FULL_TABLES
565 .It Li ACPI_LV_EVENTS
566 .It Li ACPI_LV_VERBOSE
568 .Qq Li ACPI_LV_VERBOSITY3
569 .It Li ACPI_LV_INIT_NAMES
570 Needs to be specified separately
572 Needs to be specified separately
575 Selection of the appropriate layer and level values is important
576 to avoid massive amounts of debugging output.
577 For example, the following configuration is a good way to gather initial
579 It enables debug output for both ACPICA and the
581 driver, printing basic information about errors, warnings, and progress.
582 .Bd -literal -offset indent
583 debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS"
584 debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS"
587 Debugging output by the ACPICA subsystem is prefixed with the
588 module name in lowercase, followed by a source line number.
591 code follows the same format, but
592 the module name is uppercased.
593 .Sh OVERRIDING YOUR BIOS BYTECODE
594 ACPI interprets bytecode named AML
595 (ACPI Machine Language)
596 provided by the BIOS vendor as a memory image at boot time.
597 Sometimes, the AML code contains a bug that does not appear when parsed
598 by the Microsoft implementation.
600 provides a way to override it with your own AML code to work around
601 or debug such problems.
602 Note that all AML in your DSDT and any SSDT tables is overridden.
604 In order to load your AML code, copy it to
605 .Pa /boot/kernel/acpi_dsdt.aml
606 and add the following line to
607 .Pa /boot/loader.conf .
608 .Bd -literal -offset indent
612 In order to prepare your AML code, you will need the
616 utilities and some ACPI knowledge.
618 .\"ACPI is only found and supported on i386 and x86_64.
625 .Xr acpi_panasonic 4 ,
628 .Xr acpi_thinkpad 4 ,
642 .%A "Hewlett-Packard Corporation"
643 .%A "Intel Corporation"
644 .%A "Microsoft Corporation"
645 .%A "Phoenix Technologies Ltd."
646 .%A "Toshiba Corporation"
647 .%D November 13, 2013
648 .%T "Advanced Configuration and Power Interface Specification"
649 .%O http://acpi.info/spec.htm
653 The ACPICA subsystem is developed and maintained by
654 Intel Architecture Labs.
656 The following people made notable contributions to the ACPI subsystem
660 .An Takanori Watanabe Aq Mt takawata@jp.FreeBSD.org ,
661 .An Mitsuru IWASAKI Aq Mt iwasaki@jp.FreeBSD.org ,
662 .An Munehiro Matsuda ,
664 the ACPI-jp mailing list at
665 .Aq Mt acpi-jp@jp.FreeBSD.org ,
666 and many other contributors.
668 This manual page was written by
669 .An Michael Smith Aq Mt msmith@FreeBSD.org .
671 Many BIOS versions have serious bugs that may cause system instability,
672 break suspend/resume, or prevent devices from operating properly due to
673 IRQ routing problems.
674 Upgrade your BIOS to the latest version available from the vendor before
675 deciding it is a problem with
680 .\"CPU idle power management drive conflicts with the local APIC (LAPIC)
682 .\"Disable APIC mode with
683 .\".Va hint.apic.0.disabled
688 .\"states if APIC mode is enabled.