1.\" 2.\" Copyright (c) 2001 Michael Smith 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 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. 13.\" 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 24.\" SUCH DAMAGE. 25.\" 26.\" $FreeBSD: src/share/man/man4/acpi.4,v 1.61.8.1 2009/04/15 03:14:26 kensmith Exp $ 27.\" 28.Dd November 11, 2009 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 40The 41.Nm 42driver provides support for the Intel/Microsoft/Compaq/Toshiba ACPI 43standard. 44This support includes platform hardware discovery (superseding the 45PnP and PCI BIOS), as well as power management (superseding APM) and 46other features. 47ACPI core support is provided by the ACPI CA reference implementation 48from Intel. 49.Pp 50Note that the 51.Nm 52driver is automatically loaded by the 53.Xr loader 8 , 54and should only be 55compiled into the kernel on platforms where ACPI is mandatory. 56.Sh SYSCTL VARIABLES 57The 58.Nm 59driver is intended to provide power management without user intervention. 60If the default settings are not optimal, the following sysctls can be 61used to modify or monitor 62.Nm 63behavior. 64.Bl -tag -width indent 65.It Va hw.acpi.acline 66AC line state (1 means online, 0 means on battery power). 67.It Va hw.acpi.cpu.cx_usage 68Debugging information listing the percent of total usage for each sleep state. 69The values are reset when 70.Va hw.acpi.cpu.cx_lowest 71is modified. 72.It Va hw.acpi.cpu.cx_lowest 73Lowest Cx state to use for idling the CPU. 74A scheduling algorithm will select states between 75.Li C1 76and this setting 77as system load dictates. 78To enable ACPI CPU idling control, 79.Va machdep.cpu_idle_hlt 80must be set to 2 (the default value). 81.It Va hw.acpi.cpu.cx_supported 82List of supported CPU idle states and their transition latency 83in microseconds. 84Each state has a type (e.g., 85.Li C2 ) . 86.Li C1 87is equivalent to the ia32 88.Li HLT 89instruction, 90.Li C2 91provides a deeper 92sleep with the same semantics, and 93.Li C3 94provides the deepest sleep 95but additionally requires bus mastering to be disabled. 96States greater than 97.Li C3 98provide even more power savings with the same 99semantics as the 100.Li C3 101state. 102Deeper sleeps provide more power savings but increased transition 103latency when an interrupt occurs. 104.It Va hw.acpi.disable_on_reboot 105Disable ACPI during the reboot process. 106Most systems reboot fine with ACPI still enabled, but some require 107exiting to legacy mode first. 108Default is 0, leave ACPI enabled. 109.It Va hw.acpi.handle_reboot 110Use the ACPI Reset Register capability to reboot the system. 111Default is 0, use legacy reboot support. 112Some newer systems require use of this register, while some only work 113with legacy rebooting support. 114.It Va hw.acpi.lid_switch_state 115Suspend state 116.Pq Li S1 Ns \[en] Ns Li S5 117to enter when the lid switch (i.e., a notebook screen) is closed. 118Default is 119.Dq Li NONE 120(do nothing). 121.It Va hw.acpi.power_button_state 122Suspend state 123.Pq Li S1 Ns \[en] Ns Li S5 124to enter when the power button is pressed. 125Default is 126.Li S5 127(power-off nicely). 128.It Va hw.acpi.reset_video 129Reset the video adapter from real mode during the resume path. 130Some systems need this help, others have display problems if it is enabled. 131Default is 0 (disabled). 132.It Va hw.acpi.s4bios 133Indicate whether the system supports 134.Li S4BIOS . 135This means that the BIOS can handle all the functions of suspending the 136system to disk. 137Otherwise, the OS is responsible for suspending to disk 138.Pq Li S4OS . 139Most current systems do not support 140.Li S4BIOS . 141.It Va hw.acpi.sleep_button_state 142Suspend state 143.Pq Li S1 Ns \[en] Ns Li S5 144to enter when the sleep button is pressed. 145This is usually a special function button on the keyboard. 146Default is 147.Li S3 148(suspend-to-RAM). 149.It Va hw.acpi.sleep_delay 150Wait this number of seconds between preparing the system to suspend and 151actually entering the suspend state. 152Default is 1 second. 153.It Va hw.acpi.supported_sleep_state 154Suspend states 155.Pq Li S1 Ns \[en] Ns Li S5 156supported by the BIOS. 157.Bl -tag -width indent 158.It Li S1 159Quick suspend to RAM. 160The CPU enters a lower power state, but most peripherals are left running. 161.It Li S2 162Lower power state than 163.Li S1 , 164but with the same basic characteristics. 165Not supported by many systems. 166.It Li S3 167Suspend to RAM. 168Most devices are powered off, and the system stops running except for 169memory refresh. 170.It Li S4 171Suspend to disk. 172All devices are powered off, and the system stops running. 173When resuming, the system starts as if from a cold power on. 174Not yet supported by 175.Fx 176unless 177.Li S4BIOS 178is available. 179.It Li S5 180System shuts down cleanly and powers off. 181.El 182.It Va hw.acpi.verbose 183Enable verbose printing from the various ACPI subsystems. 184.El 185.Sh LOADER TUNABLES 186Tunables can be set at the 187.Xr loader 8 188prompt before booting the kernel or stored in 189.Pa /boot/loader.conf . 190Many of these tunables also have a matching 191.Xr sysctl 8 192entry for access after boot. 193.Bl -tag -width indent 194.It Va acpi_dsdt_load 195Enables loading of a custom ACPI DSDT. 196.It Va acpi_dsdt_name 197Name of the DSDT table to load, if loading is enabled. 198.It Va debug.acpi.disabled 199Selectively disables portions of ACPI that are enabled by default, for 200debugging purposes. 201.It Va debug.acpi.enabled 202Selectively enables portions of ACPI that are disabled by default, for 203debugging purposes. 204.It Va debug.acpi.max_threads 205Specify the number of task threads that are started on boot. 206Limiting this to 1 may help work around various BIOSes that cannot 207handle parallel requests. 208The default value is 3. 209.It Va debug.acpi.quirks 210Override any automatic quirks completely. 211.It Va debug.acpi.resume_beep 212Beep the PC speaker on resume. 213This can help diagnose suspend/resume problems. 214Default is 0 (disabled). 215.It Va hint.acpi.0.disabled 216Set this to 1 to disable all of ACPI. 217If ACPI has been disabled on your system due to a blacklist entry for your 218BIOS, you can set this to 0 to re-enable ACPI for testing. 219.It Va hw.acpi.ec.poll_timeout 220Delay in milliseconds to wait for the EC to respond. 221Try increasing this number if you get the error 222.Qq Li AE_NO_HARDWARE_RESPONSE . 223.It Va hw.acpi.host_mem_start 224Override the assumed memory starting address for PCI host bridges. 225.It Va hw.acpi.reset_video 226Enables calling the VESA reset BIOS vector on the resume path. 227This can fix some graphics cards that have problems such as LCD white-out 228after resume. 229Default is 0 (disabled). 230.It Va hw.acpi.serialize_methods 231Allow override of whether methods execute in parallel or not. 232Enable this for serial behavior, which fixes 233.Qq Li AE_ALREADY_EXISTS 234errors for 235AML that really cannot handle parallel method execution. 236It is off by default since this breaks recursive methods and some IBMs use 237such code. 238.It Va hw.acpi.verbose 239Turn on verbose debugging information about what ACPI is doing. 240.It Va hw.pci.link.%s.%d.irq 241Override the interrupt to use for this link and index. 242This capability should be used carefully, and only if a device is not 243working with 244.Nm 245enabled. 246.Qq %s 247is the name of the link (e.g., LNKA). 248.Qq %d 249is the resource index when the link supports multiple IRQs. 250Most PCI links only have one IRQ resource, so the below form should be used. 251.It Va hw.pci.link.%s.irq 252Override the interrupt to use. 253This capability should be used carefully, and only if a device is not 254working with 255.Nm 256enabled. 257.Qq %s 258is the name of the link (e.g., LNKA). 259.El 260.Sh DISABLING ACPI 261Since ACPI support on different platforms varies greatly, there are many 262debugging and tuning options available. 263.Pp 264For machines known not to work with 265.Nm 266enabled, there is a BIOS blacklist. 267Currently, the blacklist only controls whether 268.Nm 269should be disabled or not. 270In the future, it will have more granularity to control features (the 271infrastructure for that is already there). 272.Pp 273To enable 274.Nm 275(for debugging purposes, etc.) on machines that are on the blacklist, set the 276kernel environment variable 277.Va hint.acpi.0.disabled 278to 0. 279Before trying this, consider updating your BIOS to a more recent version that 280may be compatible with ACPI. 281.Pp 282To disable the 283.Nm 284driver completely, set the kernel environment variable 285.Va hint.acpi.0.disabled 286to 1. 287.Pp 288Some i386 machines totally fail to operate with some or all of ACPI disabled. 289Other i386 machines fail with ACPI enabled. 290Disabling all or part of ACPI on non-i386 platforms (i.e., platforms where 291ACPI support is mandatory) may result in a non-functional system. 292.Pp 293The 294.Nm 295driver comprises a set of drivers, which may be selectively disabled 296in case of problems. 297To disable a sub-driver, list it in the kernel 298environment variable 299.Va debug.acpi.disabled . 300Multiple entries can be listed, separated by a space. 301.Pp 302ACPI sub-devices and features that can be disabled: 303.Bl -tag -width ".Li sysresource" 304.It Li all 305Disable all ACPI features and devices. 306.It Li acad 307.Pq Vt device 308Supports AC adapter. 309.It Li bus 310.Pq Vt feature 311Probes and attaches subdevices. 312Disabling will avoid scanning the ACPI namespace entirely. 313.It Li children 314.Pq Vt feature 315Attaches standard ACPI sub-drivers and devices enumerated in the 316ACPI namespace. 317Disabling this has a similar effect to disabling 318.Dq Li bus , 319except that the 320ACPI namespace will still be scanned. 321.It Li button 322.Pq Vt device 323Supports ACPI button devices (typically power and sleep buttons). 324.It Li cmbat 325.Pq Vt device 326Control-method batteries device. 327.It Li cpu 328.Pq Vt device 329Supports CPU power-saving and speed-setting functions. 330.It Li cpu_cst 331.Pq Vt device 332Supports CPU power-saving. 333Diabling 334.Dq Li cpu , 335will also disable this device. 336.It Li cpu_pst 337.Pq Vt device 338Supports CPU speed-setting. 339Diabling 340.Dq Li cpu , 341will also disable this device. 342.It Li ec 343.Pq Vt device 344Supports the ACPI Embedded Controller interface, used to communicate 345with embedded platform controllers. 346.It Li isa 347.Pq Vt device 348Supports an ISA bus bridge defined in the ACPI namespace, 349typically as a child of a PCI bus. 350.It Li lid 351.Pq Vt device 352Supports an ACPI laptop lid switch, which typically puts a 353system to sleep. 354.It Li quirks 355.Pq Vt feature 356Do not honor quirks. 357Quirks automatically disable ACPI functionality based on the XSDT table's 358OEM vendor name and revision date. 359.It Li pci 360.Pq Vt device 361Supports Host to PCI bridges. 362.It Li pci_link 363.Pq Vt feature 364Performs PCI interrupt routing. 365.It Li sysresource 366.Pq Vt device 367Pseudo-devices containing resources which ACPI claims. 368.It Li thermal 369.Pq Vt device 370Supports system cooling and heat management. 371.It Li timer 372.Pq Vt device 373Implements a timecounter using the ACPI fixed-frequency timer. 374.It Li video 375.Pq Vt device 376Supports 377.Xr acpi_video 4 378which may conflict with 379.Xr agp 4 380device. 381.El 382.Pp 383The 384.Nm 385driver comprises a set of drivers, 386which may be selectively enabled in case of testing. 387To enable a sub-driver, 388list it in the kernel environment variable 389.Va debug.acpi.enabled . 390Multiple entries can be listed, 391separated by a space. 392.Pp 393ACPI sub-devices and features that can be enabled: 394.Bl -tag -width ".Li sysresource" 395.It Li hpet 396.Pq Vt device 397Supports HPET. 398.El 399.Pp 400It is also possible to avoid portions of the ACPI namespace which 401may be causing problems, by listing the full path of the root of 402the region to be avoided in the kernel environment variable 403.Va debug.acpi.avoid . 404The object and all of its children will be ignored during the 405bus/children scan of the namespace. 406The ACPI CA code will still know about the avoided region. 407.Sh DEBUGGING OUTPUT 408To enable debugging output, 409.Nm 410must be compiled with 411.Cd "options ACPI_DEBUG" . 412Debugging output is separated between layers and levels, where a layer is 413a component of the ACPI subsystem, and a level is a particular kind 414of debugging output. 415.Pp 416Both layers and levels are specified as a whitespace-separated list of 417tokens, with layers listed in 418.Va debug.acpi.layer 419and levels in 420.Va debug.acpi.level . 421.Pp 422The first set of layers is for ACPI-CA components, and the second is for 423.Dx 424drivers. 425The ACPI-CA layer descriptions include the prefix for the files they 426refer to. 427The supported layers are: 428.Pp 429.Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER" 430.It Li ACPI_UTILITIES 431Utility ("ut") functions 432.It Li ACPI_HARDWARE 433Hardware access ("hw") 434.It Li ACPI_EVENTS 435Event and GPE ("ev") 436.It Li ACPI_TABLES 437Table access ("tb") 438.It Li ACPI_NAMESPACE 439Namespace evaluation ("ns") 440.It Li ACPI_PARSER 441AML parser ("ps") 442.It Li ACPI_DISPATCHER 443Internal representation of interpreter state ("ds") 444.It Li ACPI_EXECUTER 445Execute AML methods ("ex") 446.It Li ACPI_RESOURCES 447Resource parsing ("rs") 448.It Li ACPI_CA_DEBUGGER 449Debugger implementation ("db", "dm") 450.It Li ACPI_OS_SERVICES 451Usermode support routines ("os") 452.It Li ACPI_CA_DISASSEMBLER 453Disassembler implementation (unused) 454.It Li ACPI_ALL_COMPONENTS 455All the above ACPI-CA components 456.It Li ACPI_AC_ADAPTER 457AC adapter driver 458.It Li ACPI_BATTERY 459Control-method battery driver 460.It Li ACPI_BUS 461ACPI, ISA, and PCI bus drivers 462.It Li ACPI_BUTTON 463Power and sleep button driver 464.It Li ACPI_EC 465Embedded controller driver 466.It Li ACPI_FAN 467Fan driver 468.It Li ACPI_OEM 469Platform-specific driver for hotkeys, LED, etc. 470.It Li ACPI_POWER 471Power resource driver 472.It Li ACPI_PROCESSOR 473CPU driver 474.It Li ACPI_THERMAL 475Thermal zone driver 476.It Li ACPI_TIMER 477Timer driver 478.It Li ACPI_ALL_DRIVERS 479All the above 480.Dx 481ACPI drivers 482.El 483.Pp 484The supported levels are: 485.Pp 486.Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE" 487.It Li ACPI_LV_ERROR 488Fatal error conditions 489.It Li ACPI_LV_WARN 490Warnings and potential problems 491.It Li ACPI_LV_INIT 492Initialization progress 493.It Li ACPI_LV_DEBUG_OBJECT 494Stores to objects 495.It Li ACPI_LV_INFO 496General information and progress 497.It Li ACPI_LV_ALL_EXCEPTIONS 498All the previous levels 499.It Li ACPI_LV_INIT_NAMES 500.It Li ACPI_LV_PARSE 501.It Li ACPI_LV_LOAD 502.It Li ACPI_LV_DISPATCH 503.It Li ACPI_LV_EXEC 504.It Li ACPI_LV_NAMES 505.It Li ACPI_LV_OPREGION 506.It Li ACPI_LV_BFIELD 507.It Li ACPI_LV_TABLES 508.It Li ACPI_LV_VALUES 509.It Li ACPI_LV_OBJECTS 510.It Li ACPI_LV_RESOURCES 511.It Li ACPI_LV_USER_REQUESTS 512.It Li ACPI_LV_PACKAGE 513.It Li ACPI_LV_VERBOSITY1 514All the previous levels 515.It Li ACPI_LV_ALLOCATIONS 516.It Li ACPI_LV_FUNCTIONS 517.It Li ACPI_LV_OPTIMIZATIONS 518.It Li ACPI_LV_VERBOSITY2 519.It Li ACPI_LV_ALL 520.It Li ACPI_LV_MUTEX 521.It Li ACPI_LV_THREADS 522.It Li ACPI_LV_IO 523.It Li ACPI_LV_INTERRUPTS 524.It Li ACPI_LV_VERBOSITY3 525All the previous levels 526.It Li ACPI_LV_AML_DISASSEMBLE 527.It Li ACPI_LV_VERBOSE_INFO 528.It Li ACPI_LV_FULL_TABLES 529.It Li ACPI_LV_EVENTS 530.It Li ACPI_LV_VERBOSE 531All levels after 532.Qq Li ACPI_LV_VERBOSITY3 533.El 534.Pp 535Selection of the appropriate layer and level values is important 536to avoid massive amounts of debugging output. 537For example, the following configuration is a good way to gather initial 538information. 539It enables debug output for both ACPI-CA and the 540.Nm 541driver, printing basic information about errors, warnings, and progress. 542.Bd -literal -offset indent 543debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS" 544debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS" 545.Ed 546.Pp 547Debugging output by the ACPI CA subsystem is prefixed with the 548module name in lowercase, followed by a source line number. 549Output from the 550.Dx Ns -local 551code follows the same format, but 552the module name is uppercased. 553.Sh OVERRIDING YOUR BIOS BYTECODE 554ACPI interprets bytecode named AML 555(ACPI Machine Language) 556provided by the BIOS vendor as a memory image at boot time. 557Sometimes, the AML code contains a bug that does not appear when parsed 558by the Microsoft implementation. 559.Dx 560provides a way to override it with your own AML code to work around 561or debug such problems. 562Note that all AML in your DSDT and any SSDT tables is overridden. 563.Pp 564In order to load your AML code, you must edit 565.Pa /boot/loader.conf 566and include the following lines. 567.Bd -literal -offset indent 568acpi_dsdt_load="YES" 569acpi_dsdt_name="/boot/acpi_dsdt.aml" # You may change this name. 570.Ed 571.Pp 572In order to prepare your AML code, you will need the 573.Xr acpidump 8 574and 575.Xr iasl 8 576utilities and some ACPI knowledge. 577.Sh COMPATIBILITY 578ACPI is only found and supported on i386/ia32, ia64, and x86_64. 579.Sh SEE ALSO 580.Xr kenv 1 , 581.Xr acpi_asus 4 , 582.Xr acpi_fujitsu 4 , 583.Xr acpi_hp 4 , 584.Xr acpi_panasonic 4 , 585.Xr acpi_sony 4 , 586.Xr acpi_thermal 4 , 587.Xr acpi_thinkpad 4 , 588.Xr acpi_toshiba 4 , 589.Xr acpi_video 4 , 590.Xr aibs 4 , 591.Xr loader.conf 5 , 592.Xr acpiconf 8 , 593.Xr acpidump 8 , 594.Xr config 8 , 595.Xr iasl 8 596.Rs 597.%A "Compaq Computer Corporation" 598.%A "Intel Corporation" 599.%A "Microsoft Corporation" 600.%A "Phoenix Technologies Ltd." 601.%A "Toshiba Corporation" 602.%D August 25, 2003 603.%T "Advanced Configuration and Power Interface Specification" 604.%O http://acpi.info/spec.htm 605.Re 606.Sh AUTHORS 607.An -nosplit 608The ACPI CA subsystem is developed and maintained by 609Intel Architecture Labs. 610.Pp 611The following people made notable contributions to the ACPI subsystem 612in 613.Dx : 614.An Michael Smith , 615.An Takanori Watanabe Aq takawata@jp.FreeBSD.org , 616.An Mitsuru IWASAKI Aq iwasaki@jp.FreeBSD.org , 617.An Munehiro Matsuda , 618.An Nate Lawson , 619the ACPI-jp mailing list at 620.Aq acpi-jp@jp.FreeBSD.org , 621and many other contributors. 622.Pp 623This manual page was written by 624.An Michael Smith Aq msmith@FreeBSD.org . 625.Sh BUGS 626Many BIOS versions have serious bugs that may cause system instability, 627break suspend/resume, or prevent devices from operating properly due to 628IRQ routing problems. 629Upgrade your BIOS to the latest version available from the vendor before 630deciding it is a problem with 631.Nm . 632.\".Pp 633.\"The 634.\".Nm 635.\"CPU idle power management drive conflicts with the local APIC (LAPIC) 636.\"timer. 637.\"Disable APIC mode with 638.\".Va hint.apic.0.disabled 639.\"or do not use the 640.\".Li C2 641.\"and 642.\".Li C3 643.\"states if APIC mode is enabled. 644