Man page or keyword search:   man All Sections 1 - General Commands 2 - System Calls 3 - Subroutines, Functions 4 - Special Files 5 - File Formats 6 - Games and Screensavers 7 - Macros and Conventions 8 - Maintenence Commands 9 - Kernel Interface New Commands Server 4.4BSD AIX Alpinelinux Archlinux Aros BSDOS BSDi Bifrost CentOS Cygwin Darwin Debian DigitalUNIX DragonFly ElementaryOS Fedora FreeBSD Gentoo GhostBSD HP-UX Haiku Hurd IRIX Inferno JazzOS Kali Knoppix LinuxMint MacOSX Mageia Mandriva Manjaro Minix MirBSD NeXTSTEP NetBSD OPENSTEP OSF1 OpenBSD OpenDarwin OpenIndiana OpenMandriva OpenServer OpenSuSE OpenVMS Oracle PC-BSD Peanut Pidora Plan9 QNX Raspbian RedHat Scientific Slackware SmartOS Solaris SuSE SunOS Syllable Tru64 UNIXv7 Ubuntu Ultrix UnixWare Xenix YellowDog aLinux   9087 pages apropos Keyword Search (all sections) Output format html ascii pdf view pdf save postscript

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 tempera‐
     ture can be monitored by the envsys(4) API or the envstat(8) command.

     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 consump‐
	    tion of the machine by performing active thermal management (for
	    example, by turning on a fan) in order to reduce the temperatures.

       2.   Passive cooling means that the system reduces the power consump‐
	    tion of devices at the cost of system performance (for example, by
	    lowering 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 tem‐
     peratures, and critical, hot, and passive temperature thresholds (as sup‐
     ported 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 crit‐
     ical 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 men‐
     tioned:

     ·	 Passive cooling is not implemented.

     ·	 There is no user-controllable way to switch between active and pas‐
	 sive cooling, although the specifications support such transforms on
	 some machines.

     ·	 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 sup‐
	 ported on NetBSD.

BSD				January 9, 2011				   BSD

                             _         _         _ 
                            | |       | |       | |     
                            | |       | |       | |     
                         __ | | __ __ | | __ __ | | __  
                         \ \| |/ / \ \| |/ / \ \| |/ /  
                          \ \ / /   \ \ / /   \ \ / /   
                           \   /     \   /     \   /    
                            \_/       \_/       \_/ 

Vote for polarhome