DragonFly On-Line Manual Pages


ACPI(4) 	      DragonFly Kernel Interfaces Manual	       ACPI(4)

NAME

acpi -- Advanced Configuration and Power Management support

SYNOPSIS

device acpi options ACPI_DEBUG options DDB

DESCRIPTION

The acpi driver provides support for the Intel/Microsoft/Compaq/Toshiba ACPI standard. This support includes platform hardware discovery (super- seding the PnP and PCI BIOS), as well as power management (superseding APM) and other features. ACPI core support is provided by the ACPICA reference implementation from Intel. Note that the acpi driver is automatically loaded by the loader(8), and should only be compiled into the kernel on platforms where ACPI is manda- tory.

SYSCTL VARIABLES

The acpi driver is intended to provide power management without user intervention. If the default settings are not optimal, the following sysctls can be used to modify or monitor acpi behavior. debug.acpi.enable_debug_objects Enable dumping Debug objects without options ACPI_DEBUG. Default is 0, ignore Debug objects. hw.acpi.acline AC line state (1 means online, 0 means on battery power). hw.acpi.cpu.cx_usage Debugging information listing the percent of total usage for each sleep state. The values are reset when hw.acpi.cpu.cx_lowest is modified. hw.acpi.cpu.cx_lowest Lowest Cx state to use for idling the CPU. A scheduling algo- rithm will select states between C1 and this setting as system load dictates. To enable ACPI CPU idling control, machdep.cpu_idle_hlt must be set to 2 (the default value). hw.acpi.cpu.cx_supported List of supported CPU idle states and their transition latency in microseconds. Each state has a type (e.g., C2). C1 is equiva- lent to the ia32 HLT instruction, C2 provides a deeper sleep with the same semantics, and C3 provides the deepest sleep but addi- tionally requires bus mastering to be disabled. States greater than C3 provide even more power savings with the same semantics as the C3 state. Deeper sleeps provide more power savings but increased transition latency when an interrupt occurs. hw.acpi.disable_on_reboot Disable ACPI during the reboot process. Most systems reboot fine with ACPI still enabled, but some require exiting to legacy mode first. Default is 0, leave ACPI enabled. hw.acpi.handle_reboot Use the ACPI Reset Register capability to reboot the system. Default is 0, use legacy reboot support. Some newer systems require use of this register, while some only work with legacy rebooting support. hw.acpi.lid_switch_state Suspend state (S1-S5) to enter when the lid switch (i.e., a note- book screen) is closed. Default is ``NONE'' (do nothing). hw.acpi.power_button_state Suspend state (S1-S5) to enter when the power button is pressed. Default is S5 (power-off nicely). hw.acpi.install_interface, hw.acpi.remove_interface Install or remove OS interface(s) to control the return value of the `_OSI' query method. When an OS interface is specified in hw.acpi.install_interface, the _OSI query for the interface returns it is supported. Conversely, when an OS interface is specified in hw.acpi.remove_interface, the _OSI query returns it is not supported. Multiple interfaces can be specified in a comma-separated list and any leading white spaces will be ignored. For example, "FreeBSD, Linux" is a valid list of two interfaces "FreeBSD" and "Linux". hw.acpi.reset_video Reset the video adapter from real mode during the resume path. Some systems need this help, others have display problems if it is enabled. Default is 0 (disabled). hw.acpi.s4bios Indicate whether the system supports S4BIOS. This means that the BIOS can handle all the functions of suspending the system to disk. Otherwise, the OS is responsible for suspending to disk (S4OS). Most current systems do not support S4BIOS. hw.acpi.sleep_button_state Suspend state (S1-S5) to enter when the sleep button is pressed. This is usually a special function button on the keyboard. Default is S3 (suspend-to-RAM). hw.acpi.sleep_delay Wait this number of seconds between preparing the system to sus- pend and actually entering the suspend state. Default is 1 sec- ond. hw.acpi.supported_sleep_state Suspend states (S1-S5) supported by the BIOS. S1 Quick suspend to RAM. The CPU enters a lower power state, but most peripherals are left running. S2 Lower power state than S1, but with the same basic char- acteristics. Not supported by many systems. S3 Suspend to RAM. Most devices are powered off, and the system stops running except for memory refresh. S4 Suspend to disk. All devices are powered off, and the system stops running. When resuming, the system starts as if from a cold power on. Not yet supported by FreeBSD unless S4BIOS is available. S5 System shuts down cleanly and powers off. hw.acpi.verbose Enable verbose printing from the various ACPI subsystems.

LOADER TUNABLES

Tunables can be set at the loader(8) prompt before booting the kernel or stored in /boot/loader.conf. Many of these tunables also have a matching sysctl(8) entry for access after boot. acpi_dsdt_load Enables loading of a custom ACPI DSDT. acpi_dsdt_name Name of the DSDT table to load, if loading is enabled. It is relative to /boot/kernel. debug.acpi.disabled Selectively disables portions of ACPI that are enabled by default, for debugging purposes. debug.acpi.enabled Selectively enables portions of ACPI that are disabled by default, for debugging purposes. debug.acpi.interpreter_slack Enable less strict ACPI implementations. Default is 1, ignore common BIOS mistakes. debug.acpi.max_threads Specify the number of task threads that are started on boot. Limiting this to 1 may help work around various BIOSes that can- not handle parallel requests. The default value is 3. debug.acpi.quirks Override any automatic quirks completely. debug.acpi.resume_beep Beep the PC speaker on resume. This can help diagnose sus- pend/resume problems. Default is 0 (disabled). hint.acpi.0.disabled Set this to 1 to disable all of ACPI. If ACPI has been disabled on your system due to a blacklist entry for your BIOS, you can set this to 0 to re-enable ACPI for testing. hw.acpi.ec.poll_timeout Delay in milliseconds to wait for the EC to respond. Try increasing this number if you get the error "AE_NO_HARDWARE_RESPONSE". hw.acpi.host_mem_start Override the assumed memory starting address for PCI host bridges. hw.acpi.reset_video Enables calling the VESA reset BIOS vector on the resume path. This can fix some graphics cards that have problems such as LCD white-out after resume. Default is 0 (disabled). hw.acpi.auto_serialize_methods Auto-serialization of control methods to proactively prevent problems with ill-behaved reentrant control methods that create named ACPI objects. Default is 1 (enabled). hw.acpi.verbose Turn on verbose debugging information about what ACPI is doing. hw.pci.link.%s.%d.irq Override the interrupt to use for this link and index. This capability should be used carefully, and only if a device is not working with acpi enabled. "%s" is the name of the link (e.g., LNKA). "%d" is the resource index when the link supports multi- ple IRQs. Most PCI links only have one IRQ resource, so the below form should be used. hw.pci.link.%s.irq Override the interrupt to use. This capability should be used carefully, and only if a device is not working with acpi enabled. "%s" is the name of the link (e.g., LNKA).

DISABLING ACPI

Since ACPI support on different platforms varies greatly, there are many debugging and tuning options available. For machines known not to work with acpi enabled, there is a BIOS black- list. Currently, the blacklist only controls whether acpi should be dis- abled or not. In the future, it will have more granularity to control features (the infrastructure for that is already there). To enable acpi (for debugging purposes, etc.) on machines that are on the blacklist, set the kernel environment variable hint.acpi.0.disabled to 0. Before trying this, consider updating your BIOS to a more recent version that may be compatible with ACPI. To disable the acpi driver completely, set the kernel environment vari- able hint.acpi.0.disabled to 1. Some i386 machines totally fail to operate with some or all of ACPI dis- abled. Other i386 machines fail with ACPI enabled. Disabling all or part of ACPI on non-i386 platforms (i.e., platforms where ACPI support is mandatory) may result in a non-functional system. The acpi driver comprises a set of drivers, which may be selectively dis- abled in case of problems. To disable a sub-driver, list it in the ker- nel environment variable debug.acpi.disabled. Multiple entries can be listed, separated by a space. ACPI sub-devices and features that can be disabled: all Disable all ACPI features and devices. acad (device) Supports AC adapter. bus (feature) Probes and attaches subdevices. Disabling will avoid scanning the ACPI namespace entirely. children (feature) Attaches standard ACPI sub-drivers and devices enumerated in the ACPI namespace. Disabling this has a sim- ilar effect to disabling ``bus'', except that the ACPI namespace will still be scanned. button (device) Supports ACPI button devices (typically power and sleep buttons). cmbat (device) Control-method batteries device. cpu (device) Supports CPU power-saving and speed-setting func- tions. cpu_cst (device) Supports CPU power-saving. Disabling ``cpu'' will also disable this device. cpu_pst (device) Supports CPU speed-setting. Disabling ``cpu'' will also disable this device. dock (device) Docking station device. ec (device) Supports the ACPI Embedded Controller interface, used to communicate with embedded platform controllers. hpet (feature) Supports the High Precision Event Timer. isa (device) Supports an ISA bus bridge defined in the ACPI namespace, typically as a child of a PCI bus. lid (device) Supports an ACPI laptop lid switch, which typically puts a system to sleep. quirks (feature) Do not honor quirks. Quirks automatically disable ACPI functionality based on the XSDT table's OEM vendor name and revision date. pci (device) Supports Host to PCI bridges. pci_link (feature) Performs PCI interrupt routing. sysresource (device) Pseudo-devices containing resources which ACPI claims. thermal (device) Supports system cooling and heat management. timer (device) Implements a timecounter using the ACPI fixed-fre- quency timer. video (device) Supports acpi_video(4) which may conflict with agp(4) device. It is also possible to avoid portions of the ACPI namespace which may be causing problems, by listing the full path of the root of the region to be avoided in the kernel environment variable debug.acpi.avoid. The object and all of its children will be ignored during the bus/children scan of the namespace. The ACPICA code will still know about the avoided region.

DEBUGGING OUTPUT

To enable debugging output, acpi must be compiled with options ACPI_DEBUG. Debugging output is separated between layers and levels, where a layer is a component of the ACPI subsystem, and a level is a par- ticular kind of debugging output. Both layers and levels are specified as a whitespace-separated list of tokens, with layers listed in debug.acpi.layer and levels in debug.acpi.level. The first set of layers is for ACPICA components, and the second is for DragonFly drivers. The ACPICA layer descriptions include the prefix for the files they refer to. The supported layers are: ACPI_UTILITIES Utility ("ut") functions ACPI_HARDWARE Hardware access ("hw") ACPI_EVENTS Event and GPE ("ev") ACPI_TABLES Table access ("tb") ACPI_NAMESPACE Namespace evaluation ("ns") ACPI_PARSER AML parser ("ps") ACPI_DISPATCHER Internal representation of interpreter state ("ds") ACPI_EXECUTER Execute AML methods ("ex") ACPI_RESOURCES Resource parsing ("rs") ACPI_CA_DEBUGGER Debugger implementation ("db", "dm") ACPI_OS_SERVICES Usermode support routines ("os") ACPI_CA_DISASSEMBLER Disassembler implementation (unused) ACPI_ALL_COMPONENTS All the above ACPICA components ACPI_AC_ADAPTER AC adapter driver ACPI_BATTERY Control-method battery driver ACPI_BUS ACPI, ISA, and PCI bus drivers ACPI_BUTTON Power and sleep button driver ACPI_EC Embedded controller driver ACPI_FAN Fan driver ACPI_OEM Platform-specific driver for hotkeys, LED, etc. ACPI_POWER Power resource driver ACPI_PROCESSOR CPU driver ACPI_THERMAL Thermal zone driver ACPI_TIMER Timer driver ACPI_ALL_DRIVERS All the above DragonFly ACPI drivers The supported levels are: ACPI_LV_INIT Initialization progress ACPI_LV_DEBUG_OBJECT Stores to objects ACPI_LV_INFO General information and progress ACPI_LV_REPAIR Repair a common problem with predefined methods ACPI_LV_ALL_EXCEPTIONS All the previous levels ACPI_LV_PARSE ACPI_LV_DISPATCH ACPI_LV_EXEC ACPI_LV_NAMES ACPI_LV_OPREGION ACPI_LV_BFIELD ACPI_LV_TABLES ACPI_LV_VALUES ACPI_LV_OBJECTS ACPI_LV_RESOURCES ACPI_LV_USER_REQUESTS ACPI_LV_PACKAGE ACPI_LV_VERBOSITY1 All the previous levels ACPI_LV_ALLOCATIONS ACPI_LV_FUNCTIONS ACPI_LV_OPTIMIZATIONS ACPI_LV_VERBOSITY2 All the previous levels ACPI_LV_ALL Alias for "ACPI_LV_VERBOSITY2" ACPI_LV_MUTEX ACPI_LV_THREADS ACPI_LV_IO ACPI_LV_INTERRUPTS ACPI_LV_VERBOSITY3 All the previous levels ACPI_LV_AML_DISASSEMBLE ACPI_LV_VERBOSE_INFO ACPI_LV_FULL_TABLES ACPI_LV_EVENTS ACPI_LV_VERBOSE All levels after "ACPI_LV_VERBOSITY3" ACPI_LV_INIT_NAMES Needs to be specified separately ACPI_LV_LOAD Needs to be specified separately Selection of the appropriate layer and level values is important to avoid massive amounts of debugging output. For example, the following configu- ration is a good way to gather initial information. It enables debug output for both ACPICA and the acpi driver, printing basic information about errors, warnings, and progress. debug.acpi.layer="ACPI_ALL_COMPONENTS ACPI_ALL_DRIVERS" debug.acpi.level="ACPI_LV_ALL_EXCEPTIONS" Debugging output by the ACPICA subsystem is prefixed with the module name in lowercase, followed by a source line number. Output from the DragonFly-local code follows the same format, but the module name is uppercased.

OVERRIDING YOUR BIOS BYTECODE

ACPI interprets bytecode named AML (ACPI Machine Language) provided by the BIOS vendor as a memory image at boot time. Sometimes, the AML code contains a bug that does not appear when parsed by the Microsoft imple- mentation. DragonFly provides a way to override it with your own AML code to work around or debug such problems. Note that all AML in your DSDT and any SSDT tables is overridden. In order to load your AML code, copy it to /boot/kernel/acpi_dsdt.aml and add the following line to /boot/loader.conf. acpi_dsdt_load="YES" In order to prepare your AML code, you will need the acpidump(8) and iasl(8) utilities and some ACPI knowledge.

SEE ALSO

kenv(1), acpi_asus(4), acpi_dock(4), acpi_fujitsu(4), acpi_hp(4), acpi_panasonic(4), acpi_sony(4), acpi_thermal(4), acpi_thinkpad(4), acpi_toshiba(4), acpi_video(4), aibs(4), loader.conf(5), acpibin(8), acpiconf(8), acpidump(8), acpiexec(8), acpinames(8), acpixtract(8), config(8), iasl(8) Hewlett-Packard Corporation, Intel Corporation, Microsoft Corporation, Phoenix Technologies Ltd., and Toshiba Corporation, Advanced Configuration and Power Interface Specification, November 13, 2013, http://acpi.info/spec.htm.

AUTHORS

The ACPICA subsystem is developed and maintained by Intel Architecture Labs. The following people made notable contributions to the ACPI subsystem in DragonFly: Michael Smith, Takanori Watanabe <takawata@jp.FreeBSD.org>, Mitsuru IWASAKI <iwasaki@jp.FreeBSD.org>, Munehiro Matsuda, Nate Lawson, the ACPI-jp mailing list at <acpi-jp@jp.FreeBSD.org>, and many other con- tributors. This manual page was written by Michael Smith <msmith@FreeBSD.org>.

BUGS

Many BIOS versions have serious bugs that may cause system instability, break suspend/resume, or prevent devices from operating properly due to IRQ routing problems. Upgrade your BIOS to the latest version available from the vendor before deciding it is a problem with acpi. DragonFly 4.1 July 1, 2014 DragonFly 4.1