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.\" $FreeBSD$ 27.\" 28.Dd June 23, 2014 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. 64Note that some variables will be available only if the given hardware supports 65them (such as 66.Va hw.acpi.acline ) . 67.Bl -tag -width indent 68.It Va debug.acpi.enable_debug_objects 69Enable dumping Debug objects without 70.Cd "options ACPI_DEBUG" . 71Default is 0, ignore Debug objects. 72.It Va hw.acpi.acline 73AC line state (1 means online, 0 means on battery power). 74.It Va hw.acpi.cpu.cx_usage 75Debugging information listing the percent of total usage for each sleep state. 76The values are reset when 77.Va hw.acpi.cpu.cx_lowest 78is modified. 79.It Va hw.acpi.cpu.cx_lowest 80Lowest Cx state to use for idling the CPU. 81A scheduling algorithm will select states between 82.Li C1 83and this setting 84as system load dictates. 85To enable ACPI CPU idling control, 86.Va machdep.idle 87should be set to 88.Li acpi 89if it is listed in 90.Va machdep.idle_available . 91.It Va hw.acpi.cpu.cx_supported 92List of supported CPU idle states and their transition latency 93in microseconds. 94Each state has a type (e.g., 95.Li C2 ) . 96.Li C1 97is equivalent to the ia32 98.Li HLT 99instruction, 100.Li C2 101provides a deeper 102sleep with the same semantics, and 103.Li C3 104provides the deepest sleep 105but additionally requires bus mastering to be disabled. 106States greater than 107.Li C3 108provide even more power savings with the same 109semantics as the 110.Li C3 111state. 112Deeper sleeps provide more power savings but increased transition 113latency when an interrupt occurs. 114.It Va hw.acpi.disable_on_reboot 115Disable ACPI during the reboot process. 116Most systems reboot fine with ACPI still enabled, but some require 117exiting to legacy mode first. 118Default is 0, leave ACPI enabled. 119.It Va hw.acpi.handle_reboot 120Use the ACPI Reset Register capability to reboot the system. 121Some newer systems require use of this register, while some only work 122with legacy rebooting support. 123.It Va hw.acpi.lid_switch_state 124Suspend state 125.Pq Li S1 Ns \[en] Ns Li S5 126to enter when the lid switch (i.e., a notebook screen) is closed. 127Default is 128.Dq Li NONE 129(do nothing). 130.It Va hw.acpi.power_button_state 131Suspend state 132.Pq Li S1 Ns \[en] Ns Li S5 133to enter when the power button is pressed. 134Default is 135.Li S5 136(power-off nicely). 137.It Va hw.acpi.reset_video 138Reset the video adapter from real mode during the resume path. 139Some systems need this help, others have display problems if it is enabled. 140Default is 0 (disabled). 141.It Va hw.acpi.s4bios 142Indicate whether the system supports 143.Li S4BIOS . 144This means that the BIOS can handle all the functions of suspending the 145system to disk. 146Otherwise, the OS is responsible for suspending to disk 147.Pq Li S4OS . 148Most current systems do not support 149.Li S4BIOS . 150.It Va hw.acpi.sleep_button_state 151Suspend state 152.Pq Li S1 Ns \[en] Ns Li S5 153to enter when the sleep button is pressed. 154This is usually a special function button on the keyboard. 155Default is 156.Li S3 157(suspend-to-RAM). 158.It Va hw.acpi.sleep_delay 159Wait this number of seconds between preparing the system to suspend and 160actually entering the suspend state. 161Default is 1 second. 162.It Va hw.acpi.supported_sleep_state 163Suspend states 164.Pq Li S1 Ns \[en] Ns Li S5 165supported by the BIOS. 166.Bl -tag -width indent 167.It Li S1 168Quick suspend to RAM. 169The CPU enters a lower power state, but most peripherals are left running. 170.It Li S2 171Lower power state than 172.Li S1 , 173but with the same basic characteristics. 174Not supported by many systems. 175.It Li S3 176Suspend to RAM. 177Most devices are powered off, and the system stops running except for 178memory refresh. 179.It Li S4 180Suspend to disk. 181All devices are powered off, and the system stops running. 182When resuming, the system starts as if from a cold power on. 183Not yet supported by 184.Fx 185unless 186.Li S4BIOS 187is available. 188.It Li S5 189System shuts down cleanly and powers off. 190.El 191.It Va hw.acpi.verbose 192Enable verbose printing from the various ACPI subsystems. 193.El 194.Sh LOADER TUNABLES 195Tunables can be set at the 196.Xr loader 8 197prompt before booting the kernel or stored in 198.Pa /boot/loader.conf . 199Many of these tunables also have a matching 200.Xr sysctl 8 201entry for access after boot. 202.Bl -tag -width indent 203.It Va acpi_dsdt_load 204Enables loading of a custom ACPI DSDT. 205.It Va acpi_dsdt_name 206Name of the DSDT table to load, if loading is enabled. 207.It Va debug.acpi.cpu_unordered 208Do not use the MADT to match ACPI Processor objects to CPUs. 209This is needed on a few systems with a buggy BIOS that does not use 210consistent processor IDs. 211Default is 0 (disabled). 212.It Va debug.acpi.disabled 213Selectively disables portions of ACPI for debugging purposes. 214.It Va debug.acpi.interpreter_slack 215Enable less strict ACPI implementations. 216Default is 1, ignore common BIOS mistakes. 217.It Va debug.acpi.max_threads 218Specify the number of task threads that are started on boot. 219Limiting this to 1 may help work around various BIOSes that cannot 220handle parallel requests. 221The default value is 3. 222.It Va debug.acpi.quirks 223Override any automatic quirks completely. 224.It Va debug.acpi.resume_beep 225Beep the PC speaker on resume. 226This can help diagnose suspend/resume problems. 227Default is 0 (disabled). 228.It Va hint.acpi.0.disabled 229Set this to 1 to disable all of ACPI. 230If ACPI has been disabled on your system due to a blacklist entry for your 231BIOS, you can set this to 0 to re-enable ACPI for testing. 232.It Va hw.acpi.ec.poll_timeout 233Delay in milliseconds to wait for the EC to respond. 234Try increasing this number if you get the error 235.Qq Li AE_NO_HARDWARE_RESPONSE . 236.It Va hw.acpi.host_mem_start 237Override the assumed memory starting address for PCI host bridges. 238.It Va hw.acpi.install_interface , hw.acpi.remove_interface 239Install or remove OS interface(s) to control return value of 240.Ql _OSI 241query method. When an OS interface is specified in 242.Va hw.acpi.install_interface , 243.Li _OSI 244query for the interface returns it is 245.Em supported . 246Conversely, when an OS interface is specified in 247.Va hw.acpi.remove_interface , 248.Li _OSI 249query returns it is 250.Em not supported . 251Multiple interfaces can be specified in a comma-separated list and 252any leading white spaces will be ignored. For example, 253.Qq Li FreeBSD, Linux 254is a valid list of two interfaces 255.Qq Li FreeBSD 256and 257.Qq Li Linux . 258.It Va hw.acpi.reset_video 259Enables calling the VESA reset BIOS vector on the resume path. 260This can fix some graphics cards that have problems such as LCD white-out 261after resume. 262Default is 0 (disabled). 263.It Va hw.acpi.serialize_methods 264Allow override of whether methods execute in parallel or not. 265Enable this for serial behavior, which fixes 266.Qq Li AE_ALREADY_EXISTS 267errors for 268AML that really cannot handle parallel method execution. 269It is off by default since this breaks recursive methods and some IBMs use 270such code. 271.It Va hw.acpi.verbose 272Turn on verbose debugging information about what ACPI is doing. 273.It Va hw.pci.link.%s.%d.irq 274Override the interrupt to use for this link and index. 275This capability should be used carefully, and only if a device is not 276working with 277.Nm 278enabled. 279.Qq %s 280is the name of the link (e.g., LNKA). 281.Qq %d 282is the resource index when the link supports multiple IRQs. 283Most PCI links only have one IRQ resource, so the below form should be used. 284.It Va hw.pci.link.%s.irq 285Override the interrupt to use. 286This capability should be used carefully, and only if a device is not 287working with 288.Nm 289enabled. 290.Qq %s 291is the name of the link (e.g., LNKA). 292.El 293.Sh DISABLING ACPI 294Since ACPI support on different platforms varies greatly, there are many 295debugging and tuning options available. 296.Pp 297For machines known not to work with 298.Nm 299enabled, there is a BIOS blacklist. 300Currently, the blacklist only controls whether 301.Nm 302should be disabled or not. 303In the future, it will have more granularity to control features (the 304infrastructure for that is already there). 305.Pp 306To enable 307.Nm 308(for debugging purposes, etc.) on machines that are on the blacklist, set the 309kernel environment variable 310.Va hint.acpi.0.disabled 311to 0. 312Before trying this, consider updating your BIOS to a more recent version that 313may be compatible with ACPI. 314.Pp 315To disable the 316.Nm 317driver completely, set the kernel environment variable 318.Va hint.acpi.0.disabled 319to 1. 320.Pp 321Some i386 machines totally fail to operate with some or all of ACPI disabled. 322Other i386 machines fail with ACPI enabled. 323Disabling all or part of ACPI on non-i386 platforms (i.e., platforms where 324ACPI support is mandatory) may result in a non-functional system. 325.Pp 326The 327.Nm 328driver comprises a set of drivers, which may be selectively disabled 329in case of problems. 330To disable a sub-driver, list it in the kernel 331environment variable 332.Va debug.acpi.disabled . 333Multiple entries can be listed, separated by a space. 334.Pp 335ACPI sub-devices and features that can be disabled: 336.Bl -tag -width ".Li sysresource" 337.It Li all 338Disable all ACPI features and devices. 339.It Li acad 340.Pq Vt device 341Supports AC adapter. 342.It Li bus 343.Pq Vt feature 344Probes and attaches subdevices. 345Disabling will avoid scanning the ACPI namespace entirely. 346.It Li children 347.Pq Vt feature 348Attaches standard ACPI sub-drivers and devices enumerated in the 349ACPI namespace. 350Disabling this has a similar effect to disabling 351.Dq Li bus , 352except that the 353ACPI namespace will still be scanned. 354.It Li button 355.Pq Vt device 356Supports ACPI button devices (typically power and sleep buttons). 357.It Li cmbat 358.Pq Vt device 359Control-method batteries device. 360.It Li cpu 361.Pq Vt device 362Supports CPU power-saving and speed-setting functions. 363.It Li ec 364.Pq Vt device 365Supports the ACPI Embedded Controller interface, used to communicate 366with embedded platform controllers. 367.It Li isa 368.Pq Vt device 369Supports an ISA bus bridge defined in the ACPI namespace, 370typically as a child of a PCI bus. 371.It Li lid 372.Pq Vt device 373Supports an ACPI laptop lid switch, which typically puts a 374system to sleep. 375.It Li quirks 376.Pq Vt feature 377Do not honor quirks. 378Quirks automatically disable ACPI functionality based on the XSDT table's 379OEM vendor name and revision date. 380.It Li pci 381.Pq Vt device 382Supports Host to PCI bridges. 383.It Li pci_link 384.Pq Vt feature 385Performs PCI interrupt routing. 386.It Li sysresource 387.Pq Vt device 388Pseudo-devices containing resources which ACPI claims. 389.It Li thermal 390.Pq Vt device 391Supports system cooling and heat management. 392.It Li timer 393.Pq Vt device 394Implements a timecounter using the ACPI fixed-frequency timer. 395.It Li video 396.Pq Vt device 397Supports 398.Xr acpi_video 4 399which may conflict with 400.Xr agp 4 401device. 402.El 403.Pp 404It is also possible to avoid portions of the ACPI namespace which 405may be causing problems, by listing the full path of the root of 406the region to be avoided in the kernel environment variable 407.Va debug.acpi.avoid . 408The object and all of its children will be ignored during the 409bus/children scan of the namespace. 410The ACPI CA code will still know about the avoided region. 411.Sh DEBUGGING OUTPUT 412To enable debugging output, 413.Nm 414must be compiled with 415.Cd "options ACPI_DEBUG" . 416Debugging output is separated between layers and levels, where a layer is 417a component of the ACPI subsystem, and a level is a particular kind 418of debugging output. 419.Pp 420Both layers and levels are specified as a whitespace-separated list of 421tokens, with layers listed in 422.Va debug.acpi.layer 423and levels in 424.Va debug.acpi.level . 425.Pp 426The first set of layers is for ACPI-CA components, and the second is for 427.Fx 428drivers. 429The ACPI-CA layer descriptions include the prefix for the files they 430refer to. 431The supported layers are: 432.Pp 433.Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER" 434.It Li ACPI_UTILITIES 435Utility ("ut") functions 436.It Li ACPI_HARDWARE 437Hardware access ("hw") 438.It Li ACPI_EVENTS 439Event and GPE ("ev") 440.It Li ACPI_TABLES 441Table access ("tb") 442.It Li ACPI_NAMESPACE 443Namespace evaluation ("ns") 444.It Li ACPI_PARSER 445AML parser ("ps") 446.It Li ACPI_DISPATCHER 447Internal representation of interpreter state ("ds") 448.It Li ACPI_EXECUTER 449Execute AML methods ("ex") 450.It Li ACPI_RESOURCES 451Resource parsing ("rs") 452.It Li ACPI_CA_DEBUGGER 453Debugger implementation ("db", "dm") 454.It Li ACPI_OS_SERVICES 455Usermode support routines ("os") 456.It Li ACPI_CA_DISASSEMBLER 457Disassembler implementation (unused) 458.It Li ACPI_ALL_COMPONENTS 459All the above ACPI-CA components 460.It Li ACPI_AC_ADAPTER 461AC adapter driver 462.It Li ACPI_BATTERY 463Control-method battery driver 464.It Li ACPI_BUS 465ACPI, ISA, and PCI bus drivers 466.It Li ACPI_BUTTON 467Power and sleep button driver 468.It Li ACPI_EC 469Embedded controller driver 470.It Li ACPI_FAN 471Fan driver 472.It Li ACPI_OEM 473Platform-specific driver for hotkeys, LED, etc. 474.It Li ACPI_POWER 475Power resource driver 476.It Li ACPI_PROCESSOR 477CPU driver 478.It Li ACPI_THERMAL 479Thermal zone driver 480.It Li ACPI_TIMER 481Timer driver 482.It Li ACPI_ALL_DRIVERS 483All the above 484.Fx 485ACPI drivers 486.El 487.Pp 488The supported levels are: 489.Pp 490.Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE" 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_REPAIR 498Repair a common problem with predefined methods 499.It Li ACPI_LV_ALL_EXCEPTIONS 500All the previous levels 501.It Li ACPI_LV_PARSE 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 519All the previous levels 520.It Li ACPI_LV_ALL 521Synonym for 522.Qq Li ACPI_LV_VERBOSITY2 523.It Li ACPI_LV_MUTEX 524.It Li ACPI_LV_THREADS 525.It Li ACPI_LV_IO 526.It Li ACPI_LV_INTERRUPTS 527.It Li ACPI_LV_VERBOSITY3 528All the previous levels 529.It Li ACPI_LV_AML_DISASSEMBLE 530.It Li ACPI_LV_VERBOSE_INFO 531.It Li ACPI_LV_FULL_TABLES 532.It Li ACPI_LV_EVENTS 533.It Li ACPI_LV_VERBOSE 534All levels after 535.Qq Li ACPI_LV_VERBOSITY3 536.It Li ACPI_LV_INIT_NAMES 537.It Li ACPI_LV_LOAD 538.El 539.Pp 540Selection of the appropriate layer and level values is important 541to avoid massive amounts of debugging output. 542For example, the following configuration is a good way to gather initial 543information. 544It enables debug output for both ACPI-CA and the 545.Nm 546driver, printing basic information about errors, warnings, and progress. 547.Bd -literal -offset indent 548debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS" 549debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS" 550.Ed 551.Pp 552Debugging output by the ACPI CA subsystem is prefixed with the 553module name in lowercase, followed by a source line number. 554Output from the 555.Fx Ns -local 556code follows the same format, but 557the module name is uppercased. 558.Sh OVERRIDING YOUR BIOS BYTECODE 559ACPI interprets bytecode named AML 560(ACPI Machine Language) 561provided by the BIOS vendor as a memory image at boot time. 562Sometimes, the AML code contains a bug that does not appear when parsed 563by the Microsoft implementation. 564.Fx 565provides a way to override it with your own AML code to work around 566or debug such problems. 567Note that all AML in your DSDT and any SSDT tables is overridden. 568.Pp 569In order to load your AML code, you must edit 570.Pa /boot/loader.conf 571and include the following lines. 572.Bd -literal -offset indent 573acpi_dsdt_load="YES" 574acpi_dsdt_name="/boot/acpi_dsdt.aml" # You may change this name. 575.Ed 576.Pp 577In order to prepare your AML code, you will need the 578.Xr acpidump 8 579and 580.Xr iasl 8 581utilities and some ACPI knowledge. 582.Sh COMPATIBILITY 583ACPI is only found and supported on i386/ia32 and amd64. 584.Sh SEE ALSO 585.Xr kenv 1 , 586.Xr acpi_thermal 4 , 587.Xr device.hints 5 , 588.Xr loader.conf 5 , 589.Xr acpiconf 8 , 590.Xr acpidump 8 , 591.Xr config 8 , 592.Xr iasl 8 593.Rs 594.%A "Compaq Computer Corporation" 595.%A "Intel Corporation" 596.%A "Microsoft Corporation" 597.%A "Phoenix Technologies Ltd." 598.%A "Toshiba Corporation" 599.%D August 25, 2003 600.%T "Advanced Configuration and Power Interface Specification" 601.%U http://acpi.info/spec.htm 602.Re 603.Sh AUTHORS 604.An -nosplit 605The ACPI CA subsystem is developed and maintained by 606Intel Architecture Labs. 607.Pp 608The following people made notable contributions to the ACPI subsystem 609in 610.Fx : 611.An Michael Smith , 612.An Takanori Watanabe Aq Mt takawata@jp.FreeBSD.org , 613.An Mitsuru IWASAKI Aq Mt iwasaki@jp.FreeBSD.org , 614.An Munehiro Matsuda , 615.An Nate Lawson , 616the ACPI-jp mailing list at 617.Aq Mt acpi-jp@jp.FreeBSD.org , 618and many other contributors. 619.Pp 620This manual page was written by 621.An Michael Smith Aq Mt msmith@FreeBSD.org . 622.Sh BUGS 623Many BIOS versions have serious bugs that may cause system instability, 624break suspend/resume, or prevent devices from operating properly due to 625IRQ routing problems. 626Upgrade your BIOS to the latest version available from the vendor before 627deciding it is a problem with 628.Nm . 629.Pp 630The 631.Nm 632CPU idle power management drive conflicts with the local APIC (LAPIC) 633timer. 634Disable the local APIC timer with 635.Va hint.apic.0.clock=0 636or do not use the 637.Li C3 638and deeper states if the local APIC timer is enabled. 639