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Remove the nonsense about passive cooling. As there is no known bugs, speak
about CAVEATS instead, and add few items to this section as a TODO.
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jruoho 2010-04-25 06:04:59 +00:00
parent e494dd44d8
commit 60723a5539
1 changed files with 53 additions and 18 deletions
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share/man/man4/acpitz.4
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@ -1,4 +1,4 @@
.\" $NetBSD: acpitz.4,v 1.9 2008/11/09 14:00:48 pgoyette Exp $
.\" $NetBSD: acpitz.4,v 1.10 2010/04/25 06:04:59 jruoho Exp $
.\"
.\" Copyright (c) 2003, 2004 The NetBSD Foundation, Inc.
.\" All rights reserved.
@ -24,7 +24,7 @@
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd November 9, 2008
.Dd April 25, 2010
.Dt ACPITZ 4
.Os
.Sh NAME
@ -35,13 +35,36 @@
.Sh DESCRIPTION
The
.Nm
driver supports ACPI Thermal Zones.
.Pp
driver supports so-called
.Tn ACPI
.Dq Thermal Zones .
The temperature can be monitored by the
.Xr envsys 4
API or the
.Xr envstat 8
command.
.Pp
The distinction between
.Dq active
and
.Dq passive
cooling is central to the abstractions behind
.Nm .
These are inversely related to each other:
.Bl -enum -offset 2n
.It
Active cooling means that the system increases the power consumption of the
machine by performing active thermal management (for example, by turning on
a fan) in order to reduce the temperatures.
.It
Passive cooling means that the system reduces the power consumption of
devices at the cost of system performance (for example, by lowering the
.Tn CPU
frequencies) in order to reduce the temperatures.
.El
.Pp
Only active cooling is currently supported on
.Nx .
.Sh EVENTS
The
.Nm
@ -51,23 +74,17 @@ temperatures, and critical, hot, and passive temperature thresholds
The driver is able to send events to
.Xr powerd 8
when the sensor's state has changed.
When a Thermal Zone is critical, a
.Em critical-over
event will be sent or if the Thermal Zone is hot, a
.Em warning-over
event will be sent to the
When a Thermal Zone is either critical or
.Dq hot ,
the
.Pa /etc/powerd/scripts/sensor_temperature
script.
script will be invoked with a
.Em critical-over
event.
.Pp
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 hot temperature is the temperature threshold for S4 sleep.
.\" S4 is only supported on small subset of machines and is not known to work.
The passive temperature is the passive cooling temperature threshold.
Passive cooling means the Thermal Zone hardware
doesn't have any software control.
On capable hardware, active cooling can power on and off fans, for example.
.Sh SEE ALSO
.Xr acpi 4 ,
.Xr envsys 4 ,
@ -79,5 +96,23 @@ The
driver
appeared in
.Nx 2.0 .
.Sh BUGS
Any policy control such as fan control is not implemented.
.Sh CAVEATS
While no pronounced bugs are known to exist,
several caveats can be mentioned:
.Bl -bullet
.It
Passive cooling is not implemented.
.It
There is no user-controllable way to switch between active and passive
cooling, although the specifications support such transforms on some machines.
.It
The
.Dq hot
temperature is a threshold in which the system ought to be put into
.Tn S4
sleep.
This sleep state
.Pq Dq suspend to disk
is not supported on
.Nx .
.El