ACPITZ(4) | Device Drivers Manual | ACPITZ(4) |
acpitz
— ACPI
Thermal Zone
acpitz* at acpi?
The acpitz
driver supports so-called ACPI
“Thermal Zones”. The temperature 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:
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.
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.
The acpitz
driver appeared in
NetBSD 2.0.
Jared D. McNeill <jmcneill@invisible.ca>
While no pronounced bugs are known to exist, several caveats can be mentioned:
January 9, 2011 | NetBSD 10.99 |