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
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 ACPI CA 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 Note that some variables will be available only if the given hardware supports
66 .Va hw.acpi.acline ) .
67 .Bl -tag -width indent
68 .It Va debug.acpi.enable_debug_objects
69 Enable dumping Debug objects without
70 .Cd "options ACPI_DEBUG" .
71 Default is 0, ignore Debug objects.
72 .It Va dev.cpu.N.cx_usage
73 Debugging information listing the percent of total usage for each sleep state.
74 The values are reset when
75 .Va dev.cpu.N.cx_lowest
77 .It Va dev.cpu.N.cx_lowest
78 Lowest Cx state to use for idling the CPU.
79 A scheduling algorithm will select states between
82 as system load dictates.
83 To enable ACPI CPU idling control,
88 .Va machdep.idle_available .
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 dev.cpu.N.cx_method
113 List of supported CPU idle states and their transition methods, as
114 directed by the firmware.
115 .It Va hw.acpi.acline
116 AC line state (1 means online, 0 means on battery power).
117 .It Va hw.acpi.disable_on_reboot
118 Disable ACPI during the reboot process.
119 Most systems reboot fine with ACPI still enabled, but some require
120 exiting to legacy mode first.
121 Default is 0, leave ACPI enabled.
122 .It Va hw.acpi.handle_reboot
123 Use the ACPI Reset Register capability to reboot the system.
124 Some newer systems require use of this register, while some only work
125 with legacy rebooting support.
126 .It Va hw.acpi.lid_switch_state
128 .Pq Li S1 Ns \[en] Ns Li S5
129 to enter when the lid switch (i.e., a notebook screen) is closed.
133 .It Va hw.acpi.power_button_state
135 .Pq Li S1 Ns \[en] Ns Li S5
136 to enter when the power button is pressed.
140 .It Va hw.acpi.reset_video
141 Reset the video adapter from real mode during the resume path.
142 Some systems need this help, others have display problems if it is enabled.
143 Default is 0 (disabled).
144 .It Va hw.acpi.s4bios
145 Indicate whether the system supports
147 This means that the BIOS can handle all the functions of suspending the
149 Otherwise, the OS is responsible for suspending to disk
151 Most current systems do not support
153 .It Va hw.acpi.sleep_button_state
155 .Pq Li S1 Ns \[en] Ns Li S5
156 to enter when the sleep button is pressed.
157 This is usually a special function button on the keyboard.
161 .It Va hw.acpi.sleep_delay
162 Wait this number of seconds between preparing the system to suspend and
163 actually entering the suspend state.
165 .It Va hw.acpi.supported_sleep_state
167 .Pq Li S1 Ns \[en] Ns Li S5
168 supported by the BIOS.
169 .Bl -tag -width indent
171 Quick suspend to RAM.
172 The CPU enters a lower power state, but most peripherals are left running.
174 Lower power state than
176 but with the same basic characteristics.
177 Not supported by many systems.
180 Most devices are powered off, and the system stops running except for
184 All devices are powered off, and the system stops running.
185 When resuming, the system starts as if from a cold power on.
192 System shuts down cleanly and powers off.
194 .It Va hw.acpi.verbose
195 Enable verbose printing from the various ACPI subsystems.
198 Tunables can be set at the
200 prompt before booting the kernel or stored in
201 .Pa /boot/loader.conf .
202 Many of these tunables also have a matching
204 entry for access after boot.
205 .Bl -tag -width indent
206 .It Va acpi_dsdt_load
207 Enables loading of a custom ACPI DSDT.
208 .It Va acpi_dsdt_name
209 Name of the DSDT table to load, if loading is enabled.
210 .It Va debug.acpi.cpu_unordered
211 Do not use the MADT to match ACPI Processor objects to CPUs.
212 This is needed on a few systems with a buggy BIOS that does not use
213 consistent processor IDs.
214 Default is 0 (disabled).
215 .It Va debug.acpi.disabled
216 Selectively disables portions of ACPI for debugging purposes.
217 .It Va debug.acpi.interpreter_slack
218 Enable less strict ACPI implementations.
219 Default is 1, ignore common BIOS mistakes.
220 .It Va debug.acpi.max_threads
221 Specify the number of task threads that are started on boot.
222 Limiting this to 1 may help work around various BIOSes that cannot
223 handle parallel requests.
224 The default value is 3.
225 .It Va debug.acpi.quirks
226 Override any automatic quirks completely.
227 .It Va debug.acpi.resume_beep
228 Beep the PC speaker on resume.
229 This can help diagnose suspend/resume problems.
230 Default is 0 (disabled).
231 .It Va hint.acpi.0.disabled
232 Set this to 1 to disable all of ACPI.
233 If ACPI has been disabled on your system due to a blacklist entry for your
234 BIOS, you can set this to 0 to re-enable ACPI for testing.
235 .It Va hw.acpi.ec.poll_timeout
236 Delay in milliseconds to wait for the EC to respond.
237 Try increasing this number if you get the error
238 .Qq Li AE_NO_HARDWARE_RESPONSE .
239 .It Va hw.acpi.host_mem_start
240 Override the assumed memory starting address for PCI host bridges.
241 .It Va hw.acpi.install_interface , hw.acpi.remove_interface
242 Install or remove OS interface(s) to control return value of
245 When an OS interface is specified in
246 .Va hw.acpi.install_interface ,
248 query for the interface returns it is
250 Conversely, when an OS interface is specified in
251 .Va hw.acpi.remove_interface ,
255 Multiple interfaces can be specified in a comma-separated list and
256 any leading white spaces will be ignored.
258 .Qq Li FreeBSD, Linux
259 is a valid list of two interfaces
263 .It Va hw.acpi.reset_video
264 Enables calling the VESA reset BIOS vector on the resume path.
265 This can fix some graphics cards that have problems such as LCD white-out
267 Default is 0 (disabled).
268 .It Va hw.acpi.serialize_methods
269 Allow override of whether methods execute in parallel or not.
270 Enable this for serial behavior, which fixes
271 .Qq Li AE_ALREADY_EXISTS
273 AML that really cannot handle parallel method execution.
274 It is off by default since this breaks recursive methods and some IBMs use
276 .It Va hw.acpi.verbose
277 Turn on verbose debugging information about what ACPI is doing.
278 .It Va hw.pci.link.%s.%d.irq
279 Override the interrupt to use for this link and index.
280 This capability should be used carefully, and only if a device is not
285 is the name of the link (e.g., LNKA).
287 is the resource index when the link supports multiple IRQs.
288 Most PCI links only have one IRQ resource, so the below form should be used.
289 .It Va hw.pci.link.%s.irq
290 Override the interrupt to use.
291 This capability should be used carefully, and only if a device is not
296 is the name of the link (e.g., LNKA).
299 Since ACPI support on different platforms varies greatly, there are many
300 debugging and tuning options available.
302 For machines known not to work with
304 enabled, there is a BIOS blacklist.
305 Currently, the blacklist only controls whether
307 should be disabled or not.
308 In the future, it will have more granularity to control features (the
309 infrastructure for that is already there).
313 (for debugging purposes, etc.) on machines that are on the blacklist, set the
314 kernel environment variable
315 .Va hint.acpi.0.disabled
317 Before trying this, consider updating your BIOS to a more recent version that
318 may be compatible with ACPI.
322 driver completely, set the kernel environment variable
323 .Va hint.acpi.0.disabled
326 Some i386 machines totally fail to operate with some or all of ACPI disabled.
327 Other i386 machines fail with ACPI enabled.
328 Disabling all or part of ACPI on non-i386 platforms (i.e., platforms where
329 ACPI support is mandatory) may result in a non-functional system.
333 driver comprises a set of drivers, which may be selectively disabled
335 To disable a sub-driver, list it in the kernel
337 .Va debug.acpi.disabled .
338 Multiple entries can be listed, separated by a space.
340 ACPI sub-devices and features that can be disabled:
341 .Bl -tag -width ".Li sysresource"
343 Disable all ACPI features and devices.
349 Probes and attaches subdevices.
350 Disabling will avoid scanning the ACPI namespace entirely.
353 Attaches standard ACPI sub-drivers and devices enumerated in the
355 Disabling this has a similar effect to disabling
358 ACPI namespace will still be scanned.
361 Supports ACPI button devices (typically power and sleep buttons).
364 Control-method batteries device.
367 Supports CPU power-saving and speed-setting functions.
370 Supports the ACPI Embedded Controller interface, used to communicate
371 with embedded platform controllers.
374 Supports an ISA bus bridge defined in the ACPI namespace,
375 typically as a child of a PCI bus.
378 Supports an ACPI laptop lid switch, which typically puts a
382 Do not ask firmware for available x86-vendor specific methods to enter
385 Only query and use the generic I/O-based entrance method.
386 The knob is provided to work around inconsistencies in the tables
391 Quirks automatically disable ACPI functionality based on the XSDT table's
392 OEM vendor name and revision date.
395 Supports Host to PCI bridges.
398 Performs PCI interrupt routing.
401 Pseudo-devices containing resources which ACPI claims.
404 Supports system cooling and heat management.
407 Implements a timecounter using the ACPI fixed-frequency timer.
412 which may conflict with
417 It is also possible to avoid portions of the ACPI namespace which
418 may be causing problems, by listing the full path of the root of
419 the region to be avoided in the kernel environment variable
420 .Va debug.acpi.avoid .
421 The object and all of its children will be ignored during the
422 bus/children scan of the namespace.
423 The ACPI CA code will still know about the avoided region.
425 To enable debugging output,
427 must be compiled with
428 .Cd "options ACPI_DEBUG" .
429 Debugging output is separated between layers and levels, where a layer is
430 a component of the ACPI subsystem, and a level is a particular kind
433 Both layers and levels are specified as a whitespace-separated list of
434 tokens, with layers listed in
437 .Va debug.acpi.level .
439 The first set of layers is for ACPI-CA components, and the second is for
442 The ACPI-CA layer descriptions include the prefix for the files they
444 The supported layers are:
446 .Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER"
447 .It Li ACPI_UTILITIES
448 Utility ("ut") functions
450 Hardware access ("hw")
455 .It Li ACPI_NAMESPACE
456 Namespace evaluation ("ns")
459 .It Li ACPI_DISPATCHER
460 Internal representation of interpreter state ("ds")
462 Execute AML methods ("ex")
463 .It Li ACPI_RESOURCES
464 Resource parsing ("rs")
465 .It Li ACPI_CA_DEBUGGER
466 Debugger implementation ("db", "dm")
467 .It Li ACPI_OS_SERVICES
468 Usermode support routines ("os")
469 .It Li ACPI_CA_DISASSEMBLER
470 Disassembler implementation (unused)
471 .It Li ACPI_ALL_COMPONENTS
472 All the above ACPI-CA components
473 .It Li ACPI_AC_ADAPTER
476 Control-method battery driver
478 ACPI, ISA, and PCI bus drivers
480 Power and sleep button driver
482 Embedded controller driver
486 Platform-specific driver for hotkeys, LED, etc.
488 Power resource driver
489 .It Li ACPI_PROCESSOR
495 .It Li ACPI_ALL_DRIVERS
501 The supported levels are:
503 .Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE"
505 Initialization progress
506 .It Li ACPI_LV_DEBUG_OBJECT
509 General information and progress
510 .It Li ACPI_LV_REPAIR
511 Repair a common problem with predefined methods
512 .It Li ACPI_LV_ALL_EXCEPTIONS
513 All the previous levels
515 .It Li ACPI_LV_DISPATCH
518 .It Li ACPI_LV_OPREGION
519 .It Li ACPI_LV_BFIELD
520 .It Li ACPI_LV_TABLES
521 .It Li ACPI_LV_VALUES
522 .It Li ACPI_LV_OBJECTS
523 .It Li ACPI_LV_RESOURCES
524 .It Li ACPI_LV_USER_REQUESTS
525 .It Li ACPI_LV_PACKAGE
526 .It Li ACPI_LV_VERBOSITY1
527 All the previous levels
528 .It Li ACPI_LV_ALLOCATIONS
529 .It Li ACPI_LV_FUNCTIONS
530 .It Li ACPI_LV_OPTIMIZATIONS
531 .It Li ACPI_LV_VERBOSITY2
532 All the previous levels
535 .Qq Li ACPI_LV_VERBOSITY2
537 .It Li ACPI_LV_THREADS
539 .It Li ACPI_LV_INTERRUPTS
540 .It Li ACPI_LV_VERBOSITY3
541 All the previous levels
542 .It Li ACPI_LV_AML_DISASSEMBLE
543 .It Li ACPI_LV_VERBOSE_INFO
544 .It Li ACPI_LV_FULL_TABLES
545 .It Li ACPI_LV_EVENTS
546 .It Li ACPI_LV_VERBOSE
548 .Qq Li ACPI_LV_VERBOSITY3
549 .It Li ACPI_LV_INIT_NAMES
553 Selection of the appropriate layer and level values is important
554 to avoid massive amounts of debugging output.
555 For example, the following configuration is a good way to gather initial
557 It enables debug output for both ACPI-CA and the
559 driver, printing basic information about errors, warnings, and progress.
560 .Bd -literal -offset indent
561 debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS"
562 debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS"
565 Debugging output by the ACPI CA subsystem is prefixed with the
566 module name in lowercase, followed by a source line number.
569 code follows the same format, but
570 the module name is uppercased.
571 .Sh OVERRIDING YOUR BIOS BYTECODE
572 ACPI interprets bytecode named AML
573 (ACPI Machine Language)
574 provided by the BIOS vendor as a memory image at boot time.
575 Sometimes, the AML code contains a bug that does not appear when parsed
576 by the Microsoft implementation.
578 provides a way to override it with your own AML code to work around
579 or debug such problems.
580 Note that all AML in your DSDT and any SSDT tables is overridden.
582 In order to load your AML code, you must edit
583 .Pa /boot/loader.conf
584 and include the following lines.
585 .Bd -literal -offset indent
587 acpi_dsdt_name="/boot/acpi_dsdt.aml" # You may change this name.
590 In order to prepare your AML code, you will need the
594 utilities and some ACPI knowledge.
596 ACPI is only found and supported on i386/ia32 and amd64.
607 .%A "Compaq Computer Corporation"
608 .%A "Intel Corporation"
609 .%A "Microsoft Corporation"
610 .%A "Phoenix Technologies Ltd."
611 .%A "Toshiba Corporation"
613 .%T "Advanced Configuration and Power Interface Specification"
614 .%U http://acpi.info/spec.htm
618 The ACPI CA 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