acpitz(4) [netbsd man page]
ACPITZ(4) BSD Kernel Interfaces Manual ACPITZ(4) NAME
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 <jmcneill@invisible.ca> 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
ACPI_THERMAL(4) BSD Kernel Interfaces Manual ACPI_THERMAL(4) NAME
acpi_thermal -- ACPI thermal management subsystem SYNOPSIS
device acpi DESCRIPTION
The acpi_thermal driver provides the thermal management features of the ACPI module. This driver has a sysctl(8) interface and a devd(8) notification interface. The sysctls export properties of each ACPI thermal zone object. There can be multiple thermal zones in a system. For example, each CPU and the enclosure could all be separate thermal zones, each with its own setpoints and cooling devices. Thermal zones are numbered sequentially in the order they appear in the AML. The acpi_thermal driver also activates the active cooling system according to each thermal zone's setpoints. SYSCTL VARIABLES
hw.acpi.thermal.min_runtime Number of seconds to continue active cooling once started. A new active cooling level will not be selected until this interval expires. hw.acpi.thermal.polling_rate Number of seconds between polling the current temperature. hw.acpi.thermal.user_override If set to 1, allow user override of various setpoints (below). The original values for these settings are obtained from the BIOS and system overheating and possible damage could occur if changed. Default is 0 (no override). hw.acpi.thermal.tz%d.active Current active cooling system state. If this is non-negative, the appropriate _AC%d object is running. Set this value to the desired active cooling level to force the corresponding fan object to the appropriate level. hw.acpi.thermal.tz%d.passive_cooling If set to 1, passive cooling is enabled. It does cooling without fans using cpufreq(4) as the mechanism for controlling CPU speed. Default is enabled for tz0 where it is available. hw.acpi.thermal.tz%d.thermal_flags Current thermal zone status. These are bit-masked values. hw.acpi.thermal.tz%d.temperature Current temperature for this zone. hw.acpi.thermal.tz%d._PSV Temperature to start passive cooling by throttling down CPU, etc. This value can be overridden by the user. hw.acpi.thermal.tz%d._HOT Temperature to start critical suspend to disk (S4). This value can be overridden by the user. hw.acpi.thermal.tz%d._CRT Temperature to start critical shutdown (S5). This value can be overridden by the user. hw.acpi.thermal.tz%d._ACx Temperatures at which to switch to the corresponding active cooling level. The lower the _ACx value, the higher the cooling power. All temperatures are printed in Celsius. Values can be set in Celsius (by providing a trailing "C") or Kelvin (by leaving off any trailing letter). When setting a value by sysctl(8), do not specify a trailing decimal (i.e., 90C instead of 90.0C). NOTIFIES
Notifies are passed to userland via devd(8). See /etc/devd.conf and devd.conf(5) for examples. The acpi_thermal driver sends events with the following attributes: system ACPI subsystem Thermal type The fully qualified thermal zone object path as in the ASL. notify An integer designating the event: 0x80 Current temperature has changed. 0x81 One or more trip points (_ACx, _PSV) have changed. 0x82 One or more device lists (_ALx, _PSL, _TZD) have changed. 0xcc Non-standard notify that the system will shutdown if the temperature stays above _CRT or _HOT for one more poll cycle. SEE ALSO
acpi(4), cpufreq(4), acpidump(8) AUTHORS
Michael Smith This manual page was written by Takanori Watanabe. BSD
March 17, 2007 BSD