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 February 10, 2013 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. 333Disabling 334.Dq Li cpu 335will also disable this device. 336.It Li cpu_pst 337.Pq Vt device 338Supports CPU speed-setting. 339Disabling 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 hpet 375.Pq Vt feature 376Supports the High Precision Event Timer. 377.It Li video 378.Pq Vt device 379Supports 380.Xr acpi_video 4 381which may conflict with 382.Xr agp 4 383device. 384.El 385.Pp 386.\"The 387.\".Nm 388.\"driver comprises a set of drivers, 389.\"which may be selectively enabled in case of testing. 390.\"To enable a sub-driver, 391.\"list it in the kernel environment variable 392.\".Va debug.acpi.enabled . 393.\"Multiple entries can be listed, 394.\"separated by a space. 395.\".Pp 396.\"ACPI sub-devices and features that can be enabled: 397.\".Bl -tag -width ".Li sysresource" 398.\"[...] 399.\".El 400.\".Pp 401It is also possible to avoid portions of the ACPI namespace which 402may be causing problems, by listing the full path of the root of 403the region to be avoided in the kernel environment variable 404.Va debug.acpi.avoid . 405The object and all of its children will be ignored during the 406bus/children scan of the namespace. 407The ACPI CA code will still know about the avoided region. 408.Sh DEBUGGING OUTPUT 409To enable debugging output, 410.Nm 411must be compiled with 412.Cd "options ACPI_DEBUG" . 413Debugging output is separated between layers and levels, where a layer is 414a component of the ACPI subsystem, and a level is a particular kind 415of debugging output. 416.Pp 417Both layers and levels are specified as a whitespace-separated list of 418tokens, with layers listed in 419.Va debug.acpi.layer 420and levels in 421.Va debug.acpi.level . 422.Pp 423The first set of layers is for ACPI-CA components, and the second is for 424.Dx 425drivers. 426The ACPI-CA layer descriptions include the prefix for the files they 427refer to. 428The supported layers are: 429.Pp 430.Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER" 431.It Li ACPI_UTILITIES 432Utility ("ut") functions 433.It Li ACPI_HARDWARE 434Hardware access ("hw") 435.It Li ACPI_EVENTS 436Event and GPE ("ev") 437.It Li ACPI_TABLES 438Table access ("tb") 439.It Li ACPI_NAMESPACE 440Namespace evaluation ("ns") 441.It Li ACPI_PARSER 442AML parser ("ps") 443.It Li ACPI_DISPATCHER 444Internal representation of interpreter state ("ds") 445.It Li ACPI_EXECUTER 446Execute AML methods ("ex") 447.It Li ACPI_RESOURCES 448Resource parsing ("rs") 449.It Li ACPI_CA_DEBUGGER 450Debugger implementation ("db", "dm") 451.It Li ACPI_OS_SERVICES 452Usermode support routines ("os") 453.It Li ACPI_CA_DISASSEMBLER 454Disassembler implementation (unused) 455.It Li ACPI_ALL_COMPONENTS 456All the above ACPI-CA components 457.It Li ACPI_AC_ADAPTER 458AC adapter driver 459.It Li ACPI_BATTERY 460Control-method battery driver 461.It Li ACPI_BUS 462ACPI, ISA, and PCI bus drivers 463.It Li ACPI_BUTTON 464Power and sleep button driver 465.It Li ACPI_EC 466Embedded controller driver 467.It Li ACPI_FAN 468Fan driver 469.It Li ACPI_OEM 470Platform-specific driver for hotkeys, LED, etc. 471.It Li ACPI_POWER 472Power resource driver 473.It Li ACPI_PROCESSOR 474CPU driver 475.It Li ACPI_THERMAL 476Thermal zone driver 477.It Li ACPI_TIMER 478Timer driver 479.It Li ACPI_ALL_DRIVERS 480All the above 481.Dx 482ACPI drivers 483.El 484.Pp 485The supported levels are: 486.Pp 487.Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE" 488.It Li ACPI_LV_ERROR 489Fatal error conditions 490.It Li ACPI_LV_WARN 491Warnings and potential problems 492.It Li ACPI_LV_INIT 493Initialization progress 494.It Li ACPI_LV_DEBUG_OBJECT 495Stores to objects 496.It Li ACPI_LV_INFO 497General information and progress 498.It Li ACPI_LV_ALL_EXCEPTIONS 499All the previous levels 500.It Li ACPI_LV_INIT_NAMES 501.It Li ACPI_LV_PARSE 502.It Li ACPI_LV_LOAD 503.It Li ACPI_LV_DISPATCH 504.It Li ACPI_LV_EXEC 505.It Li ACPI_LV_NAMES 506.It Li ACPI_LV_OPREGION 507.It Li ACPI_LV_BFIELD 508.It Li ACPI_LV_TABLES 509.It Li ACPI_LV_VALUES 510.It Li ACPI_LV_OBJECTS 511.It Li ACPI_LV_RESOURCES 512.It Li ACPI_LV_USER_REQUESTS 513.It Li ACPI_LV_PACKAGE 514.It Li ACPI_LV_VERBOSITY1 515All the previous levels 516.It Li ACPI_LV_ALLOCATIONS 517.It Li ACPI_LV_FUNCTIONS 518.It Li ACPI_LV_OPTIMIZATIONS 519.It Li ACPI_LV_VERBOSITY2 520.It Li ACPI_LV_ALL 521.It Li ACPI_LV_MUTEX 522.It Li ACPI_LV_THREADS 523.It Li ACPI_LV_IO 524.It Li ACPI_LV_INTERRUPTS 525.It Li ACPI_LV_VERBOSITY3 526All the previous levels 527.It Li ACPI_LV_AML_DISASSEMBLE 528.It Li ACPI_LV_VERBOSE_INFO 529.It Li ACPI_LV_FULL_TABLES 530.It Li ACPI_LV_EVENTS 531.It Li ACPI_LV_VERBOSE 532All levels after 533.Qq Li ACPI_LV_VERBOSITY3 534.El 535.Pp 536Selection of the appropriate layer and level values is important 537to avoid massive amounts of debugging output. 538For example, the following configuration is a good way to gather initial 539information. 540It enables debug output for both ACPI-CA and the 541.Nm 542driver, printing basic information about errors, warnings, and progress. 543.Bd -literal -offset indent 544debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS" 545debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS" 546.Ed 547.Pp 548Debugging output by the ACPI CA subsystem is prefixed with the 549module name in lowercase, followed by a source line number. 550Output from the 551.Dx Ns -local 552code follows the same format, but 553the module name is uppercased. 554.Sh OVERRIDING YOUR BIOS BYTECODE 555ACPI interprets bytecode named AML 556(ACPI Machine Language) 557provided by the BIOS vendor as a memory image at boot time. 558Sometimes, the AML code contains a bug that does not appear when parsed 559by the Microsoft implementation. 560.Dx 561provides a way to override it with your own AML code to work around 562or debug such problems. 563Note that all AML in your DSDT and any SSDT tables is overridden. 564.Pp 565In order to load your AML code, you must edit 566.Pa /boot/loader.conf 567and include the following lines. 568.Bd -literal -offset indent 569acpi_dsdt_load="YES" 570acpi_dsdt_name="/boot/acpi_dsdt.aml" # You may change this name. 571.Ed 572.Pp 573In order to prepare your AML code, you will need the 574.Xr acpidump 8 575and 576.Xr iasl 8 577utilities and some ACPI knowledge. 578.Sh COMPATIBILITY 579ACPI is only found and supported on i386/ia32, ia64, and x86_64. 580.Sh SEE ALSO 581.Xr kenv 1 , 582.Xr acpi_asus 4 , 583.Xr acpi_fujitsu 4 , 584.Xr acpi_hp 4 , 585.Xr acpi_panasonic 4 , 586.Xr acpi_sony 4 , 587.Xr acpi_thermal 4 , 588.Xr acpi_thinkpad 4 , 589.Xr acpi_toshiba 4 , 590.Xr acpi_video 4 , 591.Xr aibs 4 , 592.Xr loader.conf 5 , 593.Xr acpiconf 8 , 594.Xr acpidump 8 , 595.Xr config 8 , 596.Xr iasl 8 597.Rs 598.%A "Compaq Computer Corporation" 599.%A "Intel Corporation" 600.%A "Microsoft Corporation" 601.%A "Phoenix Technologies Ltd." 602.%A "Toshiba Corporation" 603.%D August 25, 2003 604.%T "Advanced Configuration and Power Interface Specification" 605.%O http://acpi.info/spec.htm 606.Re 607.Sh AUTHORS 608.An -nosplit 609The ACPI CA subsystem is developed and maintained by 610Intel Architecture Labs. 611.Pp 612The following people made notable contributions to the ACPI subsystem 613in 614.Dx : 615.An Michael Smith , 616.An Takanori Watanabe Aq Mt takawata@jp.FreeBSD.org , 617.An Mitsuru IWASAKI Aq Mt iwasaki@jp.FreeBSD.org , 618.An Munehiro Matsuda , 619.An Nate Lawson , 620the ACPI-jp mailing list at 621.Aq Mt acpi-jp@jp.FreeBSD.org , 622and many other contributors. 623.Pp 624This manual page was written by 625.An Michael Smith Aq Mt msmith@FreeBSD.org . 626.Sh BUGS 627Many BIOS versions have serious bugs that may cause system instability, 628break suspend/resume, or prevent devices from operating properly due to 629IRQ routing problems. 630Upgrade your BIOS to the latest version available from the vendor before 631deciding it is a problem with 632.Nm . 633.\".Pp 634.\"The 635.\".Nm 636.\"CPU idle power management drive conflicts with the local APIC (LAPIC) 637.\"timer. 638.\"Disable APIC mode with 639.\".Va hint.apic.0.disabled 640.\"or do not use the 641.\".Li C2 642.\"and 643.\".Li C3 644.\"states if APIC mode is enabled. 645