[src/uebayasi-xip]: src/share/man/man4 Add also a paragraph about the platfor...

[jruoho <jruoho%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/788a6d4c1fee
branches:  uebayasi-xip
changeset: 751670:788a6d4c1fee
user:      jruoho <jruoho%NetBSD.org@localhost>
date:      Sun Apr 25 06:54:41 2010 +0000

description:
Add also a paragraph about the platform-specific nature of the thermal
management.

diffstat:

 share/man/man4/acpitz.4 |  125 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 125 insertions(+), 0 deletions(-)

diffs (129 lines):

diff -r 11928d7f5d0a -r 788a6d4c1fee share/man/man4/acpitz.4
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/share/man/man4/acpitz.4   Sun Apr 25 06:54:41 2010 +0000
@@ -0,0 +1,125 @@
+.\" $NetBSD: acpitz.4,v 1.11.2.2 2010/04/25 06:54:41 jruoho Exp $
+.\"
+.\" Copyright (c) 2003, 2004 The NetBSD Foundation, Inc.
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+.\" POSSIBILITY OF SUCH DAMAGE.
+.\"
+.Dd April 25, 2010
+.Dt ACPITZ 4
+.Os
+.Sh NAME
+.Nm acpitz
+.Nd ACPI Thermal Zone
+.Sh SYNOPSIS
+.Cd "acpitz* at acpi?"
+.Sh DESCRIPTION
+The
+.Nm
+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 .
+.Pp
+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.
+.Sh EVENTS
+The
+.Nm
+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
+.Xr powerd 8
+when the sensor's state has changed.
+When a Thermal Zone is either critical or
+.Dq hot ,
+the
+.Pa /etc/powerd/scripts/sensor_temperature
+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.
+.Sh SEE ALSO
+.Xr acpi 4 ,
+.Xr envsys 4 ,
+.Xr envstat 8 ,
+.Xr powerd 8
+.Sh HISTORY
+The
+.Nm
+driver
+appeared in
+.Nx 2.0 .
+.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