2 .\" Copyright (c) 2001 Michael Smith
3 .\" All rights reserved.
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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
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18 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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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.allow_method_calls
207 utility can be used to directly call ACPI methods for debugging and
209 .It Va debug.acpi.disabled
210 Selectively disables portions of ACPI that are enabled by default, for
212 .It Va debug.acpi.enabled
213 Selectively enables portions of ACPI that are disabled by default, for
215 .It Va debug.acpi.facs_addr32
216 Favor 32-bit FACS table addresses over the 64-bit addresses.
217 .It Va debug.acpi.fadt_addr32
218 Favor 32-bit FADT register addresses over the 64-bit addresses.
219 .It Va debug.acpi.group_module_level_code
220 Group the execution of module-level code after all of the tables have
221 been loaded instead of executing it as tables are loaded into the namespace
222 during ACPICA initialization.
223 The default is to not group.
224 .It Va debug.acpi.ignore_xsdt
225 Ignore the XSDT, forcing the use of the RSDT.
226 .It Va debug.acpi.interpreter_slack
227 Enable less strict ACPI implementations.
228 Default is 1, ignore common BIOS mistakes.
229 .It Va debug.acpi.max_threads
230 Specify the number of task threads that are started on boot.
231 Limiting this to 1 may help work around various BIOSes that cannot
232 handle parallel requests.
233 The default value is 3.
234 .It Va debug.acpi.quirks
235 Override any automatic quirks completely.
236 .It Va debug.acpi.resume_beep
237 Beep the PC speaker on resume.
238 This can help diagnose suspend/resume problems.
239 Default is 0 (disabled).
240 .It Va hint.acpi.0.disabled
241 Set this to 1 to disable all of ACPI.
242 If ACPI has been disabled on your system due to a blacklist entry for your
243 BIOS, you can set this to 0 to re-enable ACPI for testing.
244 .It Va hw.acpi.ec.poll_timeout
245 Delay in milliseconds to wait for the EC to respond.
246 Try increasing this number if you get the error
247 .Qq Li AE_NO_HARDWARE_RESPONSE .
248 .It Va hw.acpi.host_mem_start
249 Override the assumed memory starting address for PCI host bridges.
250 .It Va hw.acpi.install_interface , hw.acpi.remove_interface
251 Install or remove OS interface(s) to control the return value of the
254 When an OS interface is specified in
255 .Va hw.acpi.install_interface ,
258 query for the interface returns it is
260 Conversely, when an OS interface is specified in
261 .Va hw.acpi.remove_interface ,
266 Multiple interfaces can be specified in a comma-separated list and
267 any leading white spaces will be ignored.
269 .Qq Li FreeBSD, Linux
270 is a valid list of two interfaces
274 .It Va hw.acpi.reset_video
275 Enables calling the VESA reset BIOS vector on the resume path.
276 This can fix some graphics cards that have problems such as LCD white-out
278 Default is 0 (disabled).
279 .It Va hw.acpi.auto_serialize_methods
280 Auto-serialization of control methods to proactively prevent problems with
281 ill-behaved reentrant control methods that create named ACPI objects.
282 Default is 1 (enabled).
283 .It Va hw.acpi.verbose
284 Turn on verbose debugging information about what ACPI is doing.
285 .It Va hw.pci.link.%s.%d.irq
286 Override the interrupt to use for this link and index.
287 This capability should be used carefully, and only if a device is not
292 is the name of the link (e.g., LNKA).
294 is the resource index when the link supports multiple IRQs.
295 Most PCI links only have one IRQ resource, so the below form should be used.
296 .It Va hw.pci.link.%s.irq
297 Override the interrupt to use.
298 This capability should be used carefully, and only if a device is not
303 is the name of the link (e.g., LNKA).
306 Since ACPI support on different platforms varies greatly, there are many
307 debugging and tuning options available.
309 For machines known not to work with
311 enabled, there is a BIOS blacklist.
312 Currently, the blacklist only controls whether
314 should be disabled or not.
315 In the future, it will have more granularity to control features (the
316 infrastructure for that is already there).
320 (for debugging purposes, etc.) on machines that are on the blacklist, set the
321 kernel environment variable
322 .Va hint.acpi.0.disabled
324 Before trying this, consider updating your BIOS to a more recent version that
325 may be compatible with ACPI.
329 driver completely, set the kernel environment variable
330 .Va hint.acpi.0.disabled
333 Disabling all or part of ACPI may result in a non-functional system.
337 driver comprises a set of drivers, which may be selectively disabled
339 To disable a sub-driver, list it in the kernel
341 .Va debug.acpi.disabled .
342 Multiple entries can be listed, separated by a space.
344 ACPI sub-devices and features that can be disabled:
345 .Bl -tag -width ".Li sysresource"
347 Disable all ACPI features and devices.
353 Probes and attaches subdevices.
354 Disabling will avoid scanning the ACPI namespace entirely.
357 Attaches standard ACPI sub-drivers and devices enumerated in the
359 Disabling this has a similar effect to disabling
362 ACPI namespace will still be scanned.
365 Supports ACPI button devices (typically power and sleep buttons).
368 Control-method batteries device.
371 Supports CPU power-saving and speed-setting functions.
374 Supports CPU power-saving.
377 will also disable this device.
380 Supports CPU speed-setting.
383 will also disable this device.
386 Docking station device.
389 Supports the ACPI Embedded Controller interface, used to communicate
390 with embedded platform controllers.
393 Supports the High Precision Event Timer.
396 Supports an ISA bus bridge defined in the ACPI namespace,
397 typically as a child of a PCI bus.
400 Supports an ACPI laptop lid switch, which typically puts a
405 Quirks automatically disable ACPI functionality based on the XSDT table's
406 OEM vendor name and revision date.
409 Supports Host to PCI bridges.
412 Performs PCI interrupt routing.
415 Pseudo-devices containing resources which ACPI claims.
418 Supports system cooling and heat management.
421 Implements a timecounter using the ACPI fixed-frequency timer.
426 which may conflict with
433 .\"driver comprises a set of drivers,
434 .\"which may be selectively enabled in case of testing.
435 .\"To enable a sub-driver,
436 .\"list it in the kernel environment variable
437 .\".Va debug.acpi.enabled .
438 .\"Multiple entries can be listed,
439 .\"separated by a space.
441 .\"ACPI sub-devices and features that can be enabled:
442 .\".Bl -tag -width ".Li sysresource"
446 It is also possible to avoid portions of the ACPI namespace which
447 may be causing problems, by listing the full path of the root of
448 the region to be avoided in the kernel environment variable
449 .Va debug.acpi.avoid .
450 The object and all of its children will be ignored during the
451 bus/children scan of the namespace.
452 The ACPICA code will still know about the avoided region.
454 To enable debugging output,
456 must be compiled with
457 .Cd "options ACPI_DEBUG" .
458 Debugging output is separated between layers and levels, where a layer is
459 a component of the ACPI subsystem, and a level is a particular kind
462 Both layers and levels are specified as a whitespace-separated list of
463 tokens, with layers listed in
466 .Va debug.acpi.level .
468 The first set of layers is for ACPICA components, and the second is for
471 The ACPICA layer descriptions include the prefix for the files they
473 The supported layers are:
475 .Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER"
476 .It Li ACPI_UTILITIES
477 Utility ("ut") functions
479 Hardware access ("hw")
484 .It Li ACPI_NAMESPACE
485 Namespace evaluation ("ns")
488 .It Li ACPI_DISPATCHER
489 Internal representation of interpreter state ("ds")
491 Execute AML methods ("ex")
492 .It Li ACPI_RESOURCES
493 Resource parsing ("rs")
494 .It Li ACPI_CA_DEBUGGER
495 Debugger implementation ("db", "dm")
496 .It Li ACPI_OS_SERVICES
497 Usermode support routines ("os")
498 .It Li ACPI_CA_DISASSEMBLER
499 Disassembler implementation (unused)
500 .It Li ACPI_ALL_COMPONENTS
501 All the above ACPICA components
502 .It Li ACPI_AC_ADAPTER
505 Control-method battery driver
507 ACPI, ISA, and PCI bus drivers
509 Power and sleep button driver
511 Embedded controller driver
515 Platform-specific driver for hotkeys, LED, etc.
517 Power resource driver
518 .It Li ACPI_PROCESSOR
524 .It Li ACPI_ALL_DRIVERS
530 The supported levels are:
532 .Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE"
534 Initialization progress
535 .It Li ACPI_LV_DEBUG_OBJECT
538 General information and progress
539 .It Li ACPI_LV_REPAIR
540 Repair a common problem with predefined methods
541 .It Li ACPI_LV_ALL_EXCEPTIONS
542 All the previous levels
544 .It Li ACPI_LV_DISPATCH
547 .It Li ACPI_LV_OPREGION
548 .It Li ACPI_LV_BFIELD
549 .It Li ACPI_LV_TABLES
550 .It Li ACPI_LV_VALUES
551 .It Li ACPI_LV_OBJECTS
552 .It Li ACPI_LV_RESOURCES
553 .It Li ACPI_LV_USER_REQUESTS
554 .It Li ACPI_LV_PACKAGE
555 .It Li ACPI_LV_VERBOSITY1
556 All the previous levels
557 .It Li ACPI_LV_ALLOCATIONS
558 .It Li ACPI_LV_FUNCTIONS
559 .It Li ACPI_LV_OPTIMIZATIONS
560 .It Li ACPI_LV_VERBOSITY2
561 All the previous levels
564 .Qq Li ACPI_LV_VERBOSITY2
566 .It Li ACPI_LV_THREADS
568 .It Li ACPI_LV_INTERRUPTS
569 .It Li ACPI_LV_VERBOSITY3
570 All the previous levels
571 .It Li ACPI_LV_AML_DISASSEMBLE
572 .It Li ACPI_LV_VERBOSE_INFO
573 .It Li ACPI_LV_FULL_TABLES
574 .It Li ACPI_LV_EVENTS
575 .It Li ACPI_LV_VERBOSE
577 .Qq Li ACPI_LV_VERBOSITY3
578 .It Li ACPI_LV_INIT_NAMES
579 Needs to be specified separately
581 Needs to be specified separately
584 Selection of the appropriate layer and level values is important
585 to avoid massive amounts of debugging output.
586 For example, the following configuration is a good way to gather initial
588 It enables debug output for both ACPICA and the
590 driver, printing basic information about errors, warnings, and progress.
591 .Bd -literal -offset indent
592 debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS"
593 debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS"
596 Debugging output by the ACPICA subsystem is prefixed with the
597 module name in lowercase, followed by a source line number.
600 code follows the same format, but
601 the module name is uppercased.
602 .Sh OVERRIDING YOUR BIOS BYTECODE
603 ACPI interprets bytecode named AML
604 (ACPI Machine Language)
605 provided by the BIOS vendor as a memory image at boot time.
606 Sometimes, the AML code contains a bug that does not appear when parsed
607 by the Microsoft implementation.
609 provides a way to override it with your own AML code to work around
610 or debug such problems.
611 Note that all AML in your DSDT and any SSDT tables is overridden.
613 In order to load your AML code, copy it to
614 .Pa /boot/kernel/acpi_dsdt.aml
615 and add the following line to
616 .Pa /boot/loader.conf .
617 .Bd -literal -offset indent
621 In order to prepare your AML code, you will need the
625 utilities and some ACPI knowledge.
632 .Xr acpi_panasonic 4 ,
635 .Xr acpi_thinkpad 4 ,
650 .%A "Hewlett-Packard Corporation"
651 .%A "Intel Corporation"
652 .%A "Microsoft Corporation"
653 .%A "Phoenix Technologies Ltd."
654 .%A "Toshiba Corporation"
655 .%D November 13, 2013
656 .%T "Advanced Configuration and Power Interface Specification"
657 .%O http://acpi.info/spec.htm
661 The ACPICA subsystem is developed and maintained by
662 Intel Architecture Labs.
664 The following people made notable contributions to the ACPI subsystem
668 .An Takanori Watanabe Aq Mt takawata@jp.FreeBSD.org ,
669 .An Mitsuru IWASAKI Aq Mt iwasaki@jp.FreeBSD.org ,
670 .An Munehiro Matsuda ,
672 the ACPI-jp mailing list at
673 .Aq Mt acpi-jp@jp.FreeBSD.org ,
674 and many other contributors.
676 This manual page was written by
677 .An Michael Smith Aq Mt msmith@FreeBSD.org .
679 Many BIOS versions have serious bugs that may cause system instability,
680 break suspend/resume, or prevent devices from operating properly due to
681 IRQ routing problems.
682 Upgrade your BIOS to the latest version available from the vendor before
683 deciding it is a problem with
688 .\"CPU idle power management drive conflicts with the local APIC (LAPIC)
690 .\"Disable APIC mode with
691 .\".Va hint.apic.0.disabled
696 .\"states if APIC mode is enabled.