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2 .\" Copyright (c) 2001 Michael Smith
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25 .\"
26 .\" $FreeBSD$
27 .\"
28 .Dd July 29, 2006
29 .Dt ACPI 4
30 .Os
31 .Sh NAME
32 .Nm acpi
33 .Nd Advanced Configuration and Power Management support
34 .Sh SYNOPSIS
35 .Cd "device acpi"
36 .Pp
37 .Cd "options ACPI_DEBUG"
38 .Cd "options DDB"
39 .Sh DESCRIPTION
40 The
41 .Nm
42 driver provides support for the Intel/Microsoft/Compaq/Toshiba ACPI
43 standard.
44 This support includes platform hardware discovery (superseding the
45 PnP and PCI BIOS), as well as power management (superseding APM) and
46 other features.
47 ACPI core support is provided by the ACPI CA reference implementation
48 from Intel.
49 .Pp
50 Note that the
51 .Nm
52 driver is automatically loaded by the
53 .Xr loader 8 ,
54 and should only be
55 compiled into the kernel on platforms where ACPI is mandatory.
56 .Sh SYSCTL VARIABLES
57 The
58 .Nm
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
62 .Nm
63 behavior.
64 .Bl -tag -width indent
65 .It Va hw.acpi.acline
66 AC line state (1 means online, 0 means on battery power).
67 .It Va hw.acpi.cpu.cx_usage
68 Debugging information listing the percent of total usage for each sleep state.
69 The values are reset when
70 .Va hw.acpi.cpu.cx_lowest
71 is modified.
72 .It Va hw.acpi.cpu.cx_lowest
73 Lowest Cx state to use for idling the CPU.
74 A scheduling algorithm will select states between
75 .Li C1
76 and this setting
77 as system load dictates.
78 To enable ACPI CPU idling control,
79 .Va machdep.cpu_idle_hlt
80 must be set to 1.
81 .It Va hw.acpi.cpu.cx_supported
82 List of supported CPU idle states and their transition latency
83 in microseconds.
84 Each state has a type (e.g.,
85 .Li C2 ) .
86 .Li C1
87 is equivalent to the ia32
88 .Li HLT
89 instruction,
90 .Li C2
91 provides a deeper
92 sleep with the same semantics, and
93 .Li C3
94 provides the deepest sleep
95 but additionally requires bus mastering to be disabled.
96 States greater than
97 .Li C3
98 provide even more power savings with the same
99 semantics as the
100 .Li C3
101 state.
102 Deeper sleeps provide more power savings but increased transition
103 latency when an interrupt occurs.
104 .It Va hw.acpi.disable_on_reboot
105 Disable ACPI during the reboot process.
106 Most systems reboot fine with ACPI still enabled, but some require
107 exiting to legacy mode first.
108 Default is 0, leave ACPI enabled.
109 .It Va hw.acpi.handle_reboot
110 Use the ACPI Reset Register capability to reboot the system.
111 Default is 0, use legacy reboot support.
112 Some newer systems require use of this register, while some only work
113 with legacy rebooting support.
114 .It Va hw.acpi.lid_switch_state
115 Suspend state
116 .Pq Li S1 Ns \[en] Ns Li S5
117 to enter when the lid switch (i.e., a notebook screen) is closed.
118 Default is
119 .Dq Li NONE
120 (do nothing).
121 .It Va hw.acpi.power_button_state
122 Suspend state
123 .Pq Li S1 Ns \[en] Ns Li S5
124 to enter when the power button is pressed.
125 Default is
126 .Li S5
127 (power-off nicely).
128 .It Va hw.acpi.reset_video
129 Reset the video adapter from real mode during the resume path.
130 Some systems need this help, others have display problems if it is enabled.
131 Default is 0 (disabled).
132 .It Va hw.acpi.s4bios
133 Indicate whether the system supports
134 .Li S4BIOS .
135 This means that the BIOS can handle all the functions of suspending the
136 system to disk.
137 Otherwise, the OS is responsible for suspending to disk
138 .Pq Li S4OS .
139 Most current systems do not support
140 .Li S4BIOS .
141 .It Va hw.acpi.sleep_button_state
142 Suspend state
143 .Pq Li S1 Ns \[en] Ns Li S5
144 to enter when the sleep button is pressed.
145 This is usually a special function button on the keyboard.
146 Default is
147 .Li S3
148 (suspend-to-RAM).
149 .It Va hw.acpi.sleep_delay
150 Wait this number of seconds between preparing the system to suspend and
151 actually entering the suspend state.
152 Default is 1 second.
153 .It Va hw.acpi.supported_sleep_state
154 Suspend states
155 .Pq Li S1 Ns \[en] Ns Li S5
156 supported by the BIOS.
157 .Bl -tag -width indent
158 .It Li S1
159 Quick suspend to RAM.
160 The CPU enters a lower power state, but most peripherals are left running.
161 .It Li S2
162 Lower power state than
163 .Li S1 ,
164 but with the same basic characteristics.
165 Not supported by many systems.
166 .It Li S3
167 Suspend to RAM.
168 Most devices are powered off, and the system stops running except for
169 memory refresh.
170 .It Li S4
171 Suspend to disk.
172 All devices are powered off, and the system stops running.
173 When resuming, the system starts as if from a cold power on.
174 Not yet supported by
175 .Fx
176 unless
177 .Li S4BIOS
178 is available.
179 .It Li S5
180 System shuts down cleanly and powers off.
181 .El
182 .It Va hw.acpi.verbose
183 Enable verbose printing from the various ACPI subsystems.
184 .El
185 .Sh LOADER TUNABLES
186 Tunables can be set at the
187 .Xr loader 8
188 prompt before booting the kernel or stored in
189 .Pa /boot/loader.conf .
190 Many of these tunables also have a matching
191 .Xr sysctl 8
192 entry for access after boot.
193 .Bl -tag -width indent
194 .It Va acpi_dsdt_load
195 Enables loading of a custom ACPI DSDT.
196 .It Va acpi_dsdt_name
197 Name of the DSDT table to load, if loading is enabled.
198 .It Va debug.acpi.disabled
199 Selectively disables portions of ACPI for debugging purposes.
200 .It Va debug.acpi.max_threads
201 Specify the number of task threads that are started on boot.
202 Limiting this to 1 may help work around various BIOSes that cannot
203 handle parallel requests.
204 The default value is 3.
205 .It Va debug.acpi.quirks
206 Override any automatic quirks completely.
207 .It Va debug.acpi.resume_beep
208 Beep the PC speaker on resume.
209 This can help diagnose suspend/resume problems.
210 Default is 0 (disabled).
211 .It Va hint.acpi.0.disabled
212 Set this to 1 to disable all of ACPI.
213 If ACPI has been disabled on your system due to a blacklist entry for your
214 BIOS, you can set this to 0 to re-enable ACPI for testing.
215 .It Va hw.acpi.ec.poll_timeout
216 Delay in milliseconds to wait for the EC to respond.
217 Try increasing this number if you get the error
218 .Qq Li AE_NO_HARDWARE_RESPONSE .
219 .It Va hw.acpi.host_mem_start
220 Override the assumed memory starting address for PCI host bridges.
221 .It Va hw.acpi.reset_video
222 Enables calling the VESA reset BIOS vector on the resume path.
223 This can fix some graphics cards that have problems such as LCD white-out
224 after resume.
225 Default is 0 (disabled).
226 .It Va hw.acpi.serialize_methods
227 Allow override of whether methods execute in parallel or not.
228 Enable this for serial behavior, which fixes
229 .Qq Li AE_ALREADY_EXISTS
230 errors for
231 AML that really cannot handle parallel method execution.
232 It is off by default since this breaks recursive methods and some IBMs use
233 such code.
234 .It Va hw.acpi.verbose
235 Turn on verbose debugging information about what ACPI is doing.
236 .It Va hw.pci.link.%s.%d.irq
237 Override the interrupt to use for this link and index.
238 This capability should be used carefully, and only if a device is not
239 working with
240 .Nm
241 enabled.
242 .Qq %s
243 is the name of the link (e.g., LNKA).
244 .Qq %d
245 is the resource index when the link supports multiple IRQs.
246 Most PCI links only have one IRQ resource, so the below form should be used.
247 .It Va hw.pci.link.%s.irq
248 Override the interrupt to use.
249 This capability should be used carefully, and only if a device is not
250 working with
251 .Nm
252 enabled.
253 .Qq %s
254 is the name of the link (e.g., LNKA).
255 .El
256 .Sh DISABLING ACPI
257 Since ACPI support on different platforms varies greatly, there are many
258 debugging and tuning options available.
259 .Pp
260 For machines known not to work with
261 .Nm
262 enabled, there is a BIOS blacklist.
263 Currently, the blacklist only controls whether
264 .Nm
265 should be disabled or not.
266 In the future, it will have more granularity to control features (the
267 infrastructure for that is already there).
268 .Pp
269 To enable
270 .Nm
271 (for debugging purposes, etc.) on machines that are on the blacklist, set the
272 kernel environment variable
273 .Va hint.acpi.0.disabled
274 to 0.
275 Before trying this, consider updating your BIOS to a more recent version that
276 may be compatible with ACPI.
277 .Pp
278 To disable the
279 .Nm
280 driver completely, set the kernel environment variable
281 .Va hint.acpi.0.disabled
282 to 1.
283 .Pp
284 Some i386 machines totally fail to operate with some or all of ACPI disabled.
285 Other i386 machines fail with ACPI enabled.
286 Disabling all or part of ACPI on non-i386 platforms (i.e., platforms where
287 ACPI support is mandatory) may result in a non-functional system.
288 .Pp
289 The
290 .Nm
291 driver comprises a set of drivers, which may be selectively disabled
292 in case of problems.
293 To disable a sub-driver, list it in the kernel
294 environment variable
295 .Va debug.acpi.disabled .
296 Multiple entries can be listed, separated by a space.
297 .Pp
298 ACPI sub-devices and features that can be disabled:
299 .Bl -tag -width ".Li sysresource"
300 .It Li all
301 Disable all ACPI features and devices.
302 .It Li acad
303 .Pq Vt device
304 Supports AC adapter.
305 .It Li bus
306 .Pq Vt feature
307 Probes and attaches subdevices.
308 Disabling will avoid scanning the ACPI namespace entirely.
309 .It Li children
310 .Pq Vt feature
311 Attaches standard ACPI sub-drivers and devices enumerated in the
312 ACPI namespace.
313 Disabling this has a similar effect to disabling
314 .Dq Li bus ,
315 except that the
316 ACPI namespace will still be scanned.
317 .It Li button
318 .Pq Vt device
319 Supports ACPI button devices (typically power and sleep buttons).
320 .It Li cmbat
321 .Pq Vt device
322 Control-method batteries device.
323 .It Li cpu
324 .Pq Vt device
325 Supports CPU power-saving and speed-setting functions.
326 .It Li ec
327 .Pq Vt device
328 Supports the ACPI Embedded Controller interface, used to communicate
329 with embedded platform controllers.
330 .It Li isa
331 .Pq Vt device
332 Supports an ISA bus bridge defined in the ACPI namespace,
333 typically as a child of a PCI bus.
334 .It Li lid
335 .Pq Vt device
336 Supports an ACPI laptop lid switch, which typically puts a
337 system to sleep.
338 .It Li quirks
339 .Pq Vt feature
340 Do not honor quirks.
341 Quirks automatically disable ACPI functionality based on the XSDT table's
342 OEM vendor name and revision date.
343 .It Li pci
344 .Pq Vt device
345 Supports Host to PCI bridges.
346 .It Li pci_link
347 .Pq Vt feature
348 Performs PCI interrupt routing.
349 .It Li sysresource
350 .Pq Vt device
351 Pseudo-devices containing resources which ACPI claims.
352 .It Li thermal
353 .Pq Vt device
354 Supports system cooling and heat management.
355 .It Li timer
356 .Pq Vt device
357 Implements a timecounter using the ACPI fixed-frequency timer.
358 .It Li video
359 .Pq Vt device
360 Supports
361 .Xr acpi_video 4
362 which may conflict with
363 .Xr agp 4
364 device.
365 .El
366 .Pp
367 It is also possible to avoid portions of the ACPI namespace which
368 may be causing problems, by listing the full path of the root of
369 the region to be avoided in the kernel environment variable
370 .Va debug.acpi.avoid .
371 The object and all of its children will be ignored during the
372 bus/children scan of the namespace.
373 The ACPI CA code will still know about the avoided region.
374 .Sh DEBUGGING OUTPUT
375 To enable debugging output,
376 .Nm
377 must be compiled with
378 .Cd "options ACPI_DEBUG" .
379 Debugging output is separated between layers and levels, where a layer is
380 a component of the ACPI subsystem, and a level is a particular kind
381 of debugging output.
382 .Pp
383 Both layers and levels are specified as a whitespace-separated list of
384 tokens, with layers listed in
385 .Va debug.acpi.layer
386 and levels in
387 .Va debug.acpi.level .
388 .Pp
389 The first set of layers is for ACPI-CA components, and the second is for
390 .Fx
391 drivers.
392 The ACPI-CA layer descriptions include the prefix for the files they
393 refer to.
394 The supported layers are:
395 .Pp
396 .Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER"
397 .It Li ACPI_UTILITIES
398 Utility ("ut") functions
399 .It Li ACPI_HARDWARE
400 Hardware access ("hw")
401 .It Li ACPI_EVENTS
402 Event and GPE ("ev")
403 .It Li ACPI_TABLES
404 Table access ("tb")
405 .It Li ACPI_NAMESPACE
406 Namespace evaluation ("ns")
407 .It Li ACPI_PARSER
408 AML parser ("ps")
409 .It Li ACPI_DISPATCHER
410 Internal representation of interpreter state ("ds")
411 .It Li ACPI_EXECUTER
412 Execute AML methods ("ex")
413 .It Li ACPI_RESOURCES
414 Resource parsing ("rs")
415 .It Li ACPI_CA_DEBUGGER
416 Debugger implementation ("db", "dm")
417 .It Li ACPI_OS_SERVICES
418 Usermode support routines ("os")
419 .It Li ACPI_CA_DISASSEMBLER
420 Disassembler implementation (unused)
421 .It Li ACPI_ALL_COMPONENTS
422 All the above ACPI-CA components
423 .It Li ACPI_AC_ADAPTER
424 AC adapter driver
425 .It Li ACPI_BATTERY
426 Control-method battery driver
427 .It Li ACPI_BUS
428 ACPI, ISA, and PCI bus drivers
429 .It Li ACPI_BUTTON
430 Power and sleep button driver
431 .It Li ACPI_EC
432 Embedded controller driver
433 .It Li ACPI_FAN
434 Fan driver
435 .It Li ACPI_OEM
436 Platform-specific driver for hotkeys, LED, etc.
437 .It Li ACPI_POWER
438 Power resource driver
439 .It Li ACPI_PROCESSOR
440 CPU driver
441 .It Li ACPI_THERMAL
442 Thermal zone driver
443 .It Li ACPI_TIMER
444 Timer driver
445 .It Li ACPI_ALL_DRIVERS
446 All the above
447 .Fx
448 ACPI drivers
449 .El
450 .Pp
451 The supported levels are:
452 .Pp
453 .Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE"
454 .It Li ACPI_LV_ERROR
455 Fatal error conditions
456 .It Li ACPI_LV_WARN
457 Warnings and potential problems
458 .It Li ACPI_LV_INIT
459 Initialization progress
460 .It Li ACPI_LV_DEBUG_OBJECT
461 Stores to objects
462 .It Li ACPI_LV_INFO
463 General information and progress
464 .It Li ACPI_LV_ALL_EXCEPTIONS
465 All the previous levels
466 .It Li ACPI_LV_INIT_NAMES
467 .It Li ACPI_LV_PARSE
468 .It Li ACPI_LV_LOAD
469 .It Li ACPI_LV_DISPATCH
470 .It Li ACPI_LV_EXEC
471 .It Li ACPI_LV_NAMES
472 .It Li ACPI_LV_OPREGION
473 .It Li ACPI_LV_BFIELD
474 .It Li ACPI_LV_TABLES
475 .It Li ACPI_LV_VALUES
476 .It Li ACPI_LV_OBJECTS
477 .It Li ACPI_LV_RESOURCES
478 .It Li ACPI_LV_USER_REQUESTS
479 .It Li ACPI_LV_PACKAGE
480 .It Li ACPI_LV_VERBOSITY1
481 All the previous levels
482 .It Li ACPI_LV_ALLOCATIONS
483 .It Li ACPI_LV_FUNCTIONS
484 .It Li ACPI_LV_OPTIMIZATIONS
485 .It Li ACPI_LV_VERBOSITY2
486 .It Li ACPI_LV_ALL
487 .It Li ACPI_LV_MUTEX
488 .It Li ACPI_LV_THREADS
489 .It Li ACPI_LV_IO
490 .It Li ACPI_LV_INTERRUPTS
491 .It Li ACPI_LV_VERBOSITY3
492 All the previous levels
493 .It Li ACPI_LV_AML_DISASSEMBLE
494 .It Li ACPI_LV_VERBOSE_INFO
495 .It Li ACPI_LV_FULL_TABLES
496 .It Li ACPI_LV_EVENTS
497 .It Li ACPI_LV_VERBOSE
498 All levels after
499 .Qq Li ACPI_LV_VERBOSITY3
500 .El
501 .Pp
502 Selection of the appropriate layer and level values is important
503 to avoid massive amounts of debugging output.
504 For example, the following configuration is a good way to gather initial
505 information.
506 It enables debug output for both ACPI-CA and the
507 .Nm
508 driver, printing basic information about errors, warnings, and progress.
509 .Bd -literal -offset indent
510 debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS"
511 debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS"
512 .Ed
513 .Pp
514 Debugging output by the ACPI CA subsystem is prefixed with the
515 module name in lowercase, followed by a source line number.
516 Output from the
517 .Fx Ns -local
518 code follows the same format, but
519 the module name is uppercased.
520 .Sh OVERRIDING YOUR BIOS BYTECODE
521 ACPI interprets bytecode named AML
522 (ACPI Machine Language)
523 provided by the BIOS vendor as a memory image at boot time.
524 Sometimes, the AML code contains a bug that does not appear when parsed
525 by the Microsoft implementation.
526 .Fx
527 provides a way to override it with your own AML code to work around
528 or debug such problems.
529 Note that all AML in your DSDT and any SSDT tables is overridden.
530 .Pp
531 In order to load your AML code, you must edit
532 .Pa /boot/loader.conf
533 and include the following lines.
534 .Bd -literal -offset indent
535 acpi_dsdt_load="YES"
536 acpi_dsdt_name="/boot/acpi_dsdt.aml" # You may change this name.
537 .Ed
538 .Pp
539 In order to prepare your AML code, you will need the
540 .Xr acpidump 8
541 and
542 .Xr iasl 8
543 utilities and some ACPI knowledge.
544 .Sh COMPATIBILITY
545 ACPI is only found and supported on i386/ia32, ia64, and amd64.
546 .Sh SEE ALSO
547 .Xr kenv 1 ,
548 .Xr acpi_thermal 4 ,
549 .Xr device.hints 5 ,
550 .Xr loader.conf 5 ,
551 .Xr acpiconf 8 ,
552 .Xr acpidump 8 ,
553 .Xr config 8 ,
554 .Xr iasl 8
555 .Rs
556 .%A "Compaq Computer Corporation"
557 .%A "Intel Corporation"
558 .%A "Microsoft Corporation"
559 .%A "Phoenix Technologies Ltd."
560 .%A "Toshiba Corporation"
561 .%D August 25, 2003
562 .%T "Advanced Configuration and Power Interface Specification"
563 .%O http://acpi.info/spec.htm
564 .Re
565 .Sh AUTHORS
566 .An -nosplit
567 The ACPI CA subsystem is developed and maintained by
568 Intel Architecture Labs.
569 .Pp
570 The following people made notable contributions to the ACPI subsystem
571 in
572 .Fx :
573 .An Michael Smith ,
574 .An Takanori Watanabe Aq takawata@jp.FreeBSD.org ,
575 .An Mitsuru IWASAKI Aq iwasaki@jp.FreeBSD.org ,
576 .An Munehiro Matsuda ,
577 .An Nate Lawson ,
578 the ACPI-jp mailing list at
579 .Aq acpi-jp@jp.FreeBSD.org ,
580 and many other contributors.
581 .Pp
582 This manual page was written by
583 .An Michael Smith Aq msmith@FreeBSD.org .
584 .Sh BUGS
585 Many BIOS versions have serious bugs that may cause system instability,
586 break suspend/resume, or prevent devices from operating properly due to
587 IRQ routing problems.
588 Upgrade your BIOS to the latest version available from the vendor before
589 deciding it is a problem with
590 .Nm .
591 .Pp
592 The
593 .Nm
594 CPU idle power management drive conflicts with the local APIC (LAPIC)
595 timer.
596 Disable APIC mode with
597 .Va hint.apic.0.disabled
598 or do not use the
599 .Li C2
600 and
601 .Li C3
602 states if APIC mode is enabled.