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acpitz(4) [netbsd man page]

ACPITZ(4)						   BSD Kernel Interfaces Manual 						 ACPITZ(4)

acpitz -- ACPI Thermal Zone SYNOPSIS
acpitz* at acpi? DESCRIPTION
The acpitz driver supports so-called ACPI ``Thermal Zones''. The temperature can be monitored by the envsys(4) API or the envstat(8) com- mand. The distinction between ``active'' and ``passive'' cooling is central to the abstractions behind acpitz. These are inversely related to each other: 1. Active cooling means that the system increases the power consumption of the machine by performing active thermal management (for exam- ple, by turning on a fan) in order to reduce the temperatures. 2. Passive cooling means that the system reduces the power consumption of devices at the cost of system performance (for example, by low- ering the CPU frequencies) in order to reduce the temperatures. Only active cooling is currently supported on NetBSD. It should be also noted that the internal functioning of these cooling policies vary across machines. On some machines the operating system may have little control over the thermal zones as the firmware manages the thermal control internally, whereas on other machines the policies may be exposed to the implementation at their full extent. EVENTS
The acpitz driver knows about the active cooling levels, the current temperatures, and critical, hot, and passive temperature thresholds (as supported by the hardware). The driver is able to send events to powerd(8) when the sensor's state has changed. When a Thermal Zone is either critical or ``hot'', the /etc/powerd/scripts/sensor_temperature script will be invoked with a critical-over event. The critical temperature is the threshold for system shutdown. Depending on the hardware, the mainboard will take down the system instantly and no event will have a chance to be sent. SEE ALSO
acpi(4), acpifan(4), envsys(4), envstat(8), powerd(8) HISTORY
The acpitz driver appeared in NetBSD 2.0. AUTHORS
Jared D. McNeill <> CAVEATS
While no pronounced bugs are known to exist, several caveats can be mentioned: o Passive cooling is not implemented. o There is no user-controllable way to switch between active and passive cooling, although the specifications support such transforms on some machines. o The ``hot'' temperature is a threshold in which the system ought to be put into S4 sleep. This sleep state (``suspend to disk'') is not supported on NetBSD. BSD
January 9, 2011 BSD

Check Out this Related Man Page

tzmon(7d)							      Devices								 tzmon(7d)

tzmon - ACPI Thermal Zone Monitor DESCRIPTION
The tzmon is a pseudo driver that serves as an ACPI thermal zone monitor. Thermal zones are logical regions within a computer system for which ACPI performs temperature monitoring and control functions. The number of thermal zones on a system with ACPI support varies. For example, some systems may have one or more thermal zones, while others may have none. See the Advanced Configuration and Power Interface Specification, (ACPI) Version 3.0A. for more details. The tzmon handles thermal Zone events from ACPI and polls the temperature for each zone exposed by the ACPI implementation. If threshold temperatures are reached, tzmon takes appropriate action. For example, if the temperature is sufficiently high and the ACPI implementation supports it, tzmon initiates system shutdown. Note that by default, system temperature control functions are usually performed by the BIOS and may supersede tzmon functions, depending on the BIOS implementation. Also, many ACPI implementations expose no thermal zones and in these cases, tzmon performs no functions. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWckr | +-----------------------------+-----------------------------+ |Architecture |x86/x64 only | +-----------------------------+-----------------------------+ |Interface stability |Private | +-----------------------------+-----------------------------+ SEE ALSO
attributes(5) Advanced Configuration and Power Interface Specification, (ACPI), Version 3.0A. SunOS 5.11 31 Oct 2006 tzmon(7d)
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