The acpifan device driver supports fans possibly exposed
by the BIOS. Even if a system contains only one physical fan, multiple
acpifan instances may be present. In such cases each
acpifan typically represents an
acpitz(4) thermal zone, and the
combined state of all instances reveals the speed of the fan.
The acpifan driver does not support
controlling the fan. The current state (on or off) is made available through
the envsys(4) API and the
envstat(8) command.
The acpifan device driver appeared in
NetBSD 6.0.
Jukka Ruohonen ⟨jruohonen@iki.fi⟩
The acpifan driver does not yet support additional
functionality introduced in the ACPI 4.0 specification.