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. 242When an OS interface is specified in 243.Va hw.acpi.install_interface , 244.Li _OSI 245query for the interface returns it is 246.Em supported . 247Conversely, when an OS interface is specified in 248.Va hw.acpi.remove_interface , 249.Li _OSI 250query returns it is 251.Em not supported . 252Multiple interfaces can be specified in a comma-separated list and 253any leading white spaces will be ignored. 254For example, 255.Qq Li FreeBSD, Linux 256is a valid list of two interfaces 257.Qq Li FreeBSD 258and 259.Qq Li Linux . 260.It Va hw.acpi.reset_video 261Enables calling the VESA reset BIOS vector on the resume path. 262This can fix some graphics cards that have problems such as LCD white-out 263after resume. 264Default is 0 (disabled). 265.It Va hw.acpi.serialize_methods 266Allow override of whether methods execute in parallel or not. 267Enable this for serial behavior, which fixes 268.Qq Li AE_ALREADY_EXISTS 269errors for 270AML that really cannot handle parallel method execution. 271It is off by default since this breaks recursive methods and some IBMs use 272such code. 273.It Va hw.acpi.verbose 274Turn on verbose debugging information about what ACPI is doing. 275.It Va hw.pci.link.%s.%d.irq 276Override the interrupt to use for this link and index. 277This capability should be used carefully, and only if a device is not 278working with 279.Nm 280enabled. 281.Qq %s 282is the name of the link (e.g., LNKA). 283.Qq %d 284is the resource index when the link supports multiple IRQs. 285Most PCI links only have one IRQ resource, so the below form should be used. 286.It Va hw.pci.link.%s.irq 287Override the interrupt to use. 288This capability should be used carefully, and only if a device is not 289working with 290.Nm 291enabled. 292.Qq %s 293is the name of the link (e.g., LNKA). 294.El 295.Sh DISABLING ACPI 296Since ACPI support on different platforms varies greatly, there are many 297debugging and tuning options available. 298.Pp 299For machines known not to work with 300.Nm 301enabled, there is a BIOS blacklist. 302Currently, the blacklist only controls whether 303.Nm 304should be disabled or not. 305In the future, it will have more granularity to control features (the 306infrastructure for that is already there). 307.Pp 308To enable 309.Nm 310(for debugging purposes, etc.) on machines that are on the blacklist, set the 311kernel environment variable 312.Va hint.acpi.0.disabled 313to 0. 314Before trying this, consider updating your BIOS to a more recent version that 315may be compatible with ACPI. 316.Pp 317To disable the 318.Nm 319driver completely, set the kernel environment variable 320.Va hint.acpi.0.disabled 321to 1. 322.Pp 323Some i386 machines totally fail to operate with some or all of ACPI disabled. 324Other i386 machines fail with ACPI enabled. 325Disabling all or part of ACPI on non-i386 platforms (i.e., platforms where 326ACPI support is mandatory) may result in a non-functional system. 327.Pp 328The 329.Nm 330driver comprises a set of drivers, which may be selectively disabled 331in case of problems. 332To disable a sub-driver, list it in the kernel 333environment variable 334.Va debug.acpi.disabled . 335Multiple entries can be listed, separated by a space. 336.Pp 337ACPI sub-devices and features that can be disabled: 338.Bl -tag -width ".Li sysresource" 339.It Li all 340Disable all ACPI features and devices. 341.It Li acad 342.Pq Vt device 343Supports AC adapter. 344.It Li bus 345.Pq Vt feature 346Probes and attaches subdevices. 347Disabling will avoid scanning the ACPI namespace entirely. 348.It Li children 349.Pq Vt feature 350Attaches standard ACPI sub-drivers and devices enumerated in the 351ACPI namespace. 352Disabling this has a similar effect to disabling 353.Dq Li bus , 354except that the 355ACPI namespace will still be scanned. 356.It Li button 357.Pq Vt device 358Supports ACPI button devices (typically power and sleep buttons). 359.It Li cmbat 360.Pq Vt device 361Control-method batteries device. 362.It Li cpu 363.Pq Vt device 364Supports CPU power-saving and speed-setting functions. 365.It Li ec 366.Pq Vt device 367Supports the ACPI Embedded Controller interface, used to communicate 368with embedded platform controllers. 369.It Li isa 370.Pq Vt device 371Supports an ISA bus bridge defined in the ACPI namespace, 372typically as a child of a PCI bus. 373.It Li lid 374.Pq Vt device 375Supports an ACPI laptop lid switch, which typically puts a 376system to sleep. 377.It Li quirks 378.Pq Vt feature 379Do not honor quirks. 380Quirks automatically disable ACPI functionality based on the XSDT table's 381OEM vendor name and revision date. 382.It Li pci 383.Pq Vt device 384Supports Host to PCI bridges. 385.It Li pci_link 386.Pq Vt feature 387Performs PCI interrupt routing. 388.It Li sysresource 389.Pq Vt device 390Pseudo-devices containing resources which ACPI claims. 391.It Li thermal 392.Pq Vt device 393Supports system cooling and heat management. 394.It Li timer 395.Pq Vt device 396Implements a timecounter using the ACPI fixed-frequency timer. 397.It Li video 398.Pq Vt device 399Supports 400.Xr acpi_video 4 401which may conflict with 402.Xr agp 4 403device. 404.El 405.Pp 406It is also possible to avoid portions of the ACPI namespace which 407may be causing problems, by listing the full path of the root of 408the region to be avoided in the kernel environment variable 409.Va debug.acpi.avoid . 410The object and all of its children will be ignored during the 411bus/children scan of the namespace. 412The ACPI CA code will still know about the avoided region. 413.Sh DEBUGGING OUTPUT 414To enable debugging output, 415.Nm 416must be compiled with 417.Cd "options ACPI_DEBUG" . 418Debugging output is separated between layers and levels, where a layer is 419a component of the ACPI subsystem, and a level is a particular kind 420of debugging output. 421.Pp 422Both layers and levels are specified as a whitespace-separated list of 423tokens, with layers listed in 424.Va debug.acpi.layer 425and levels in 426.Va debug.acpi.level . 427.Pp 428The first set of layers is for ACPI-CA components, and the second is for 429.Fx 430drivers. 431The ACPI-CA layer descriptions include the prefix for the files they 432refer to. 433The supported layers are: 434.Pp 435.Bl -tag -compact -width ".Li ACPI_CA_DISASSEMBLER" 436.It Li ACPI_UTILITIES 437Utility ("ut") functions 438.It Li ACPI_HARDWARE 439Hardware access ("hw") 440.It Li ACPI_EVENTS 441Event and GPE ("ev") 442.It Li ACPI_TABLES 443Table access ("tb") 444.It Li ACPI_NAMESPACE 445Namespace evaluation ("ns") 446.It Li ACPI_PARSER 447AML parser ("ps") 448.It Li ACPI_DISPATCHER 449Internal representation of interpreter state ("ds") 450.It Li ACPI_EXECUTER 451Execute AML methods ("ex") 452.It Li ACPI_RESOURCES 453Resource parsing ("rs") 454.It Li ACPI_CA_DEBUGGER 455Debugger implementation ("db", "dm") 456.It Li ACPI_OS_SERVICES 457Usermode support routines ("os") 458.It Li ACPI_CA_DISASSEMBLER 459Disassembler implementation (unused) 460.It Li ACPI_ALL_COMPONENTS 461All the above ACPI-CA components 462.It Li ACPI_AC_ADAPTER 463AC adapter driver 464.It Li ACPI_BATTERY 465Control-method battery driver 466.It Li ACPI_BUS 467ACPI, ISA, and PCI bus drivers 468.It Li ACPI_BUTTON 469Power and sleep button driver 470.It Li ACPI_EC 471Embedded controller driver 472.It Li ACPI_FAN 473Fan driver 474.It Li ACPI_OEM 475Platform-specific driver for hotkeys, LED, etc. 476.It Li ACPI_POWER 477Power resource driver 478.It Li ACPI_PROCESSOR 479CPU driver 480.It Li ACPI_THERMAL 481Thermal zone driver 482.It Li ACPI_TIMER 483Timer driver 484.It Li ACPI_ALL_DRIVERS 485All the above 486.Fx 487ACPI drivers 488.El 489.Pp 490The supported levels are: 491.Pp 492.Bl -tag -compact -width ".Li ACPI_LV_AML_DISASSEMBLE" 493.It Li ACPI_LV_INIT 494Initialization progress 495.It Li ACPI_LV_DEBUG_OBJECT 496Stores to objects 497.It Li ACPI_LV_INFO 498General information and progress 499.It Li ACPI_LV_REPAIR 500Repair a common problem with predefined methods 501.It Li ACPI_LV_ALL_EXCEPTIONS 502All the previous levels 503.It Li ACPI_LV_PARSE 504.It Li ACPI_LV_DISPATCH 505.It Li ACPI_LV_EXEC 506.It Li ACPI_LV_NAMES 507.It Li ACPI_LV_OPREGION 508.It Li ACPI_LV_BFIELD 509.It Li ACPI_LV_TABLES 510.It Li ACPI_LV_VALUES 511.It Li ACPI_LV_OBJECTS 512.It Li ACPI_LV_RESOURCES 513.It Li ACPI_LV_USER_REQUESTS 514.It Li ACPI_LV_PACKAGE 515.It Li ACPI_LV_VERBOSITY1 516All the previous levels 517.It Li ACPI_LV_ALLOCATIONS 518.It Li ACPI_LV_FUNCTIONS 519.It Li ACPI_LV_OPTIMIZATIONS 520.It Li ACPI_LV_VERBOSITY2 521All the previous levels 522.It Li ACPI_LV_ALL 523Synonym for 524.Qq Li ACPI_LV_VERBOSITY2 525.It Li ACPI_LV_MUTEX 526.It Li ACPI_LV_THREADS 527.It Li ACPI_LV_IO 528.It Li ACPI_LV_INTERRUPTS 529.It Li ACPI_LV_VERBOSITY3 530All the previous levels 531.It Li ACPI_LV_AML_DISASSEMBLE 532.It Li ACPI_LV_VERBOSE_INFO 533.It Li ACPI_LV_FULL_TABLES 534.It Li ACPI_LV_EVENTS 535.It Li ACPI_LV_VERBOSE 536All levels after 537.Qq Li ACPI_LV_VERBOSITY3 538.It Li ACPI_LV_INIT_NAMES 539.It Li ACPI_LV_LOAD 540.El 541.Pp 542Selection of the appropriate layer and level values is important 543to avoid massive amounts of debugging output. 544For example, the following configuration is a good way to gather initial 545information. 546It enables debug output for both ACPI-CA and the 547.Nm 548driver, printing basic information about errors, warnings, and progress. 549.Bd -literal -offset indent 550debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS" 551debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS" 552.Ed 553.Pp 554Debugging output by the ACPI CA subsystem is prefixed with the 555module name in lowercase, followed by a source line number. 556Output from the 557.Fx Ns -local 558code follows the same format, but 559the module name is uppercased. 560.Sh OVERRIDING YOUR BIOS BYTECODE 561ACPI interprets bytecode named AML 562(ACPI Machine Language) 563provided by the BIOS vendor as a memory image at boot time. 564Sometimes, the AML code contains a bug that does not appear when parsed 565by the Microsoft implementation. 566.Fx 567provides a way to override it with your own AML code to work around 568or debug such problems. 569Note that all AML in your DSDT and any SSDT tables is overridden. 570.Pp 571In order to load your AML code, you must edit 572.Pa /boot/loader.conf 573and include the following lines. 574.Bd -literal -offset indent 575acpi_dsdt_load="YES" 576acpi_dsdt_name="/boot/acpi_dsdt.aml" # You may change this name. 577.Ed 578.Pp 579In order to prepare your AML code, you will need the 580.Xr acpidump 8 581and 582.Xr iasl 8 583utilities and some ACPI knowledge. 584.Sh COMPATIBILITY 585ACPI is only found and supported on i386/ia32 and amd64. 586.Sh SEE ALSO 587.Xr kenv 1 , 588.Xr acpi_thermal 4 , 589.Xr device.hints 5 , 590.Xr loader.conf 5 , 591.Xr acpiconf 8 , 592.Xr acpidump 8 , 593.Xr config 8 , 594.Xr iasl 8 595.Rs 596.%A "Compaq Computer Corporation" 597.%A "Intel Corporation" 598.%A "Microsoft Corporation" 599.%A "Phoenix Technologies Ltd." 600.%A "Toshiba Corporation" 601.%D August 25, 2003 602.%T "Advanced Configuration and Power Interface Specification" 603.%U http://acpi.info/spec.htm 604.Re 605.Sh AUTHORS 606.An -nosplit 607The ACPI CA subsystem is developed and maintained by 608Intel Architecture Labs. 609.Pp 610The following people made notable contributions to the ACPI subsystem 611in 612.Fx : 613.An Michael Smith , 614.An Takanori Watanabe Aq Mt takawata@jp.FreeBSD.org , 615.An Mitsuru IWASAKI Aq Mt iwasaki@jp.FreeBSD.org , 616.An Munehiro Matsuda , 617.An Nate Lawson , 618the ACPI-jp mailing list at 619.Aq Mt acpi-jp@jp.FreeBSD.org , 620and many other contributors. 621.Pp 622This manual page was written by 623.An Michael Smith Aq Mt msmith@FreeBSD.org . 624.Sh BUGS 625Many BIOS versions have serious bugs that may cause system instability, 626break suspend/resume, or prevent devices from operating properly due to 627IRQ routing problems. 628Upgrade your BIOS to the latest version available from the vendor before 629deciding it is a problem with 630.Nm . 631