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 .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
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 Some newer systems require use of this register, while some only work
116 with legacy rebooting support.
117 .It Va hw.acpi.lid_switch_state
119 .Pq Li S1 Ns \[en] Ns Li S5
120 to enter when the lid switch (i.e., a notebook screen) is closed.
124 .It Va hw.acpi.power_button_state
126 .Pq Li S1 Ns \[en] Ns Li S5
127 to enter when the power button is pressed.
131 .It Va hw.acpi.reset_video
132 Reset the video adapter from real mode during the resume path.
133 Some systems need this help, others have display problems if it is enabled.
134 Default is 0 (disabled).
135 .It Va hw.acpi.s4bios
136 Indicate whether the system supports
138 This means that the BIOS can handle all the functions of suspending the
140 Otherwise, the OS is responsible for suspending to disk
142 Most current systems do not support
144 .It Va hw.acpi.sleep_button_state
146 .Pq Li S1 Ns \[en] Ns Li S5
147 to enter when the sleep button is pressed.
148 This is usually a special function button on the keyboard.
152 .It Va hw.acpi.sleep_delay
153 Wait this number of seconds between preparing the system to suspend and
154 actually entering the suspend state.
156 .It Va hw.acpi.supported_sleep_state
158 .Pq Li S1 Ns \[en] Ns Li S5
159 supported by the BIOS.
160 .Bl -tag -width indent
162 Quick suspend to RAM.
163 The CPU enters a lower power state, but most peripherals are left running.
165 Lower power state than
167 but with the same basic characteristics.
168 Not supported by many systems.
171 Most devices are powered off, and the system stops running except for
175 All devices are powered off, and the system stops running.
176 When resuming, the system starts as if from a cold power on.
183 System shuts down cleanly and powers off.
185 .It Va hw.acpi.verbose
186 Enable verbose printing from the various ACPI subsystems.
189 Tunables can be set at the
191 prompt before booting the kernel or stored in
192 .Pa /boot/loader.conf .
193 Many of these tunables also have a matching
195 entry for access after boot.
196 .Bl -tag -width indent
197 .It Va acpi_dsdt_load
198 Enables loading of a custom ACPI DSDT.
199 .It Va acpi_dsdt_name
200 Name of the DSDT table to load, if loading is enabled.
201 .It Va debug.acpi.disabled
202 Selectively disables portions of ACPI for debugging purposes.
203 .It Va debug.acpi.interpreter_slack
204 Enable less strict ACPI implementations.
205 Default is 1, ignore common BIOS mistakes.
206 .It Va debug.acpi.max_threads
207 Specify the number of task threads that are started on boot.
208 Limiting this to 1 may help work around various BIOSes that cannot
209 handle parallel requests.
210 The default value is 3.
211 .It Va debug.acpi.quirks
212 Override any automatic quirks completely.
213 .It Va debug.acpi.resume_beep
214 Beep the PC speaker on resume.
215 This can help diagnose suspend/resume problems.
216 Default is 0 (disabled).
217 .It Va hint.acpi.0.disabled
218 Set this to 1 to disable all of ACPI.
219 If ACPI has been disabled on your system due to a blacklist entry for your
220 BIOS, you can set this to 0 to re-enable ACPI for testing.
221 .It Va hw.acpi.ec.poll_timeout
222 Delay in milliseconds to wait for the EC to respond.
223 Try increasing this number if you get the error
224 .Qq Li AE_NO_HARDWARE_RESPONSE .
225 .It Va hw.acpi.host_mem_start
226 Override the assumed memory starting address for PCI host bridges.
227 .It Va hw.acpi.install_interface , hw.acpi.remove_interface
228 Install or remove OS interface(s) to control return value of
230 query method. When an OS interface is specified in
231 .Va hw.acpi.install_interface ,
233 query for the interface returns it is
235 Conversely, when an OS interface is specified in
236 .Va hw.acpi.remove_interface ,
240 Multiple interfaces can be specified in a comma-separated list and
241 any leading white spaces will be ignored. For example,
242 .Qq Li FreeBSD, Linux
243 is a valid list of two interfaces
247 .It Va hw.acpi.reset_video
248 Enables calling the VESA reset BIOS vector on the resume path.
249 This can fix some graphics cards that have problems such as LCD white-out
251 Default is 0 (disabled).
252 .It Va hw.acpi.serialize_methods
253 Allow override of whether methods execute in parallel or not.
254 Enable this for serial behavior, which fixes
255 .Qq Li AE_ALREADY_EXISTS
257 AML that really cannot handle parallel method execution.
258 It is off by default since this breaks recursive methods and some IBMs use
260 .It Va hw.acpi.verbose
261 Turn on verbose debugging information about what ACPI is doing.
262 .It Va hw.pci.link.%s.%d.irq
263 Override the interrupt to use for this link and index.
264 This capability should be used carefully, and only if a device is not
269 is the name of the link (e.g., LNKA).
271 is the resource index when the link supports multiple IRQs.
272 Most PCI links only have one IRQ resource, so the below form should be used.
273 .It Va hw.pci.link.%s.irq
274 Override the interrupt to use.
275 This capability should be used carefully, and only if a device is not
280 is the name of the link (e.g., LNKA).
283 Since ACPI support on different platforms varies greatly, there are many
284 debugging and tuning options available.
286 For machines known not to work with
288 enabled, there is a BIOS blacklist.
289 Currently, the blacklist only controls whether
291 should be disabled or not.
292 In the future, it will have more granularity to control features (the
293 infrastructure for that is already there).
297 (for debugging purposes, etc.) on machines that are on the blacklist, set the
298 kernel environment variable
299 .Va hint.acpi.0.disabled
301 Before trying this, consider updating your BIOS to a more recent version that
302 may be compatible with ACPI.
306 driver completely, set the kernel environment variable
307 .Va hint.acpi.0.disabled
310 Some i386 machines totally fail to operate with some or all of ACPI disabled.
311 Other i386 machines fail with ACPI enabled.
312 Disabling all or part of ACPI on non-i386 platforms (i.e., platforms where
313 ACPI support is mandatory) may result in a non-functional system.
317 driver comprises a set of drivers, which may be selectively disabled
319 To disable a sub-driver, list it in the kernel
321 .Va debug.acpi.disabled .
322 Multiple entries can be listed, separated by a space.
324 ACPI sub-devices and features that can be disabled:
325 .Bl -tag -width ".Li sysresource"
327 Disable all ACPI features and devices.
333 Probes and attaches subdevices.
334 Disabling will avoid scanning the ACPI namespace entirely.
337 Attaches standard ACPI sub-drivers and devices enumerated in the
339 Disabling this has a similar effect to disabling
342 ACPI namespace will still be scanned.
345 Supports ACPI button devices (typically power and sleep buttons).
348 Control-method batteries device.
351 Supports CPU power-saving and speed-setting functions.
354 Supports the ACPI Embedded Controller interface, used to communicate
355 with embedded platform controllers.
358 Supports an ISA bus bridge defined in the ACPI namespace,
359 typically as a child of a PCI bus.
362 Supports an ACPI laptop lid switch, which typically puts a
367 Quirks automatically disable ACPI functionality based on the XSDT table's
368 OEM vendor name and revision date.
371 Supports Host to PCI bridges.
374 Performs PCI interrupt routing.
377 Pseudo-devices containing resources which ACPI claims.
380 Supports system cooling and heat management.
383 Implements a timecounter using the ACPI fixed-frequency timer.
388 which may conflict with
393 It is also possible to avoid portions of the ACPI namespace which
394 may be causing problems, by listing the full path of the root of
395 the region to be avoided in the kernel environment variable
396 .Va debug.acpi.avoid .
397 The object and all of its children will be ignored during the
398 bus/children scan of the namespace.
399 The ACPI CA code will still know about the avoided region.
401 To enable debugging output,
403 must be compiled with
404 .Cd "options ACPI_DEBUG" .
405 Debugging output is separated between layers and levels, where a layer is
406 a component of the ACPI subsystem, and a level is a particular kind
409 Both layers and levels are specified as a whitespace-separated list of
410 tokens, with layers listed in
413 .Va debug.acpi.level .
415 The first set of layers is for ACPI-CA components, and the second is for
418 The ACPI-CA layer descriptions include the prefix for the files they
420 The supported layers are:
422 .Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER"
423 .It Li ACPI_UTILITIES
424 Utility ("ut") functions
426 Hardware access ("hw")
431 .It Li ACPI_NAMESPACE
432 Namespace evaluation ("ns")
435 .It Li ACPI_DISPATCHER
436 Internal representation of interpreter state ("ds")
438 Execute AML methods ("ex")
439 .It Li ACPI_RESOURCES
440 Resource parsing ("rs")
441 .It Li ACPI_CA_DEBUGGER
442 Debugger implementation ("db", "dm")
443 .It Li ACPI_OS_SERVICES
444 Usermode support routines ("os")
445 .It Li ACPI_CA_DISASSEMBLER
446 Disassembler implementation (unused)
447 .It Li ACPI_ALL_COMPONENTS
448 All the above ACPI-CA components
449 .It Li ACPI_AC_ADAPTER
452 Control-method battery driver
454 ACPI, ISA, and PCI bus drivers
456 Power and sleep button driver
458 Embedded controller driver
462 Platform-specific driver for hotkeys, LED, etc.
464 Power resource driver
465 .It Li ACPI_PROCESSOR
471 .It Li ACPI_ALL_DRIVERS
477 The supported levels are:
479 .Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE"
481 Initialization progress
482 .It Li ACPI_LV_DEBUG_OBJECT
485 General information and progress
486 .It Li ACPI_LV_ALL_EXCEPTIONS
487 All the previous levels
489 .It Li ACPI_LV_DISPATCH
492 .It Li ACPI_LV_OPREGION
493 .It Li ACPI_LV_BFIELD
494 .It Li ACPI_LV_TABLES
495 .It Li ACPI_LV_VALUES
496 .It Li ACPI_LV_OBJECTS
497 .It Li ACPI_LV_RESOURCES
498 .It Li ACPI_LV_USER_REQUESTS
499 .It Li ACPI_LV_PACKAGE
500 .It Li ACPI_LV_VERBOSITY1
501 All the previous levels
502 .It Li ACPI_LV_ALLOCATIONS
503 .It Li ACPI_LV_FUNCTIONS
504 .It Li ACPI_LV_OPTIMIZATIONS
505 .It Li ACPI_LV_VERBOSITY2
506 All the previous levels
509 .Qq Li ACPI_LV_VERBOSITY2
511 .It Li ACPI_LV_THREADS
513 .It Li ACPI_LV_INTERRUPTS
514 .It Li ACPI_LV_VERBOSITY3
515 All the previous levels
516 .It Li ACPI_LV_AML_DISASSEMBLE
517 .It Li ACPI_LV_VERBOSE_INFO
518 .It Li ACPI_LV_FULL_TABLES
519 .It Li ACPI_LV_EVENTS
520 .It Li ACPI_LV_VERBOSE
522 .Qq Li ACPI_LV_VERBOSITY3
523 .It Li ACPI_LV_INIT_NAMES
527 Selection of the appropriate layer and level values is important
528 to avoid massive amounts of debugging output.
529 For example, the following configuration is a good way to gather initial
531 It enables debug output for both ACPI-CA and the
533 driver, printing basic information about errors, warnings, and progress.
534 .Bd -literal -offset indent
535 debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS"
536 debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS"
539 Debugging output by the ACPI CA subsystem is prefixed with the
540 module name in lowercase, followed by a source line number.
543 code follows the same format, but
544 the module name is uppercased.
545 .Sh OVERRIDING YOUR BIOS BYTECODE
546 ACPI interprets bytecode named AML
547 (ACPI Machine Language)
548 provided by the BIOS vendor as a memory image at boot time.
549 Sometimes, the AML code contains a bug that does not appear when parsed
550 by the Microsoft implementation.
552 provides a way to override it with your own AML code to work around
553 or debug such problems.
554 Note that all AML in your DSDT and any SSDT tables is overridden.
556 In order to load your AML code, you must edit
557 .Pa /boot/loader.conf
558 and include the following lines.
559 .Bd -literal -offset indent
561 acpi_dsdt_name="/boot/acpi_dsdt.aml" # You may change this name.
564 In order to prepare your AML code, you will need the
568 utilities and some ACPI knowledge.
570 ACPI is only found and supported on i386/ia32, ia64, and amd64.
581 .%A "Compaq Computer Corporation"
582 .%A "Intel Corporation"
583 .%A "Microsoft Corporation"
584 .%A "Phoenix Technologies Ltd."
585 .%A "Toshiba Corporation"
587 .%T "Advanced Configuration and Power Interface Specification"
588 .%O http://acpi.info/spec.htm
592 The ACPI CA subsystem is developed and maintained by
593 Intel Architecture Labs.
595 The following people made notable contributions to the ACPI subsystem
599 .An Takanori Watanabe Aq takawata@jp.FreeBSD.org ,
600 .An Mitsuru IWASAKI Aq iwasaki@jp.FreeBSD.org ,
601 .An Munehiro Matsuda ,
603 the ACPI-jp mailing list at
604 .Aq acpi-jp@jp.FreeBSD.org ,
605 and many other contributors.
607 This manual page was written by
608 .An Michael Smith Aq msmith@FreeBSD.org .
610 Many BIOS versions have serious bugs that may cause system instability,
611 break suspend/resume, or prevent devices from operating properly due to
612 IRQ routing problems.
613 Upgrade your BIOS to the latest version available from the vendor before
614 deciding it is a problem with
619 CPU idle power management drive conflicts with the local APIC (LAPIC)
621 Disable the local APIC timer with
622 .Va hint.apic.0.clock=0
625 and deeper states if the local APIC timer is enabled.