athcool - control power-saving mode on AMD Athlon/Duron CPUs

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1. Introduction
--------------------------------------------

athcool is a program that controls the power-saving mode on AMD Athlon/Duron
CPUs.

Since enabling power-saving mode, you can save power consumption, 
lower CPU temprature when CPU is idle.

athcool only sets/unsets the "Disconnect enable when STPGNT detected"
bit in the northbridge of the chipset.
To save power, someone has to send the STPGNT signal when the CPU is
idle.
This is done by the ACPI subsystem when the C2 state is entered.
Hence, you need ACPI support in your kernel to achieve power savings.

!!!WARNING!!!
Depending on your motherboard and/or hardware components, 
enabling Athlon powersaving mode may cause:

 * noisy or distorted sound playback
 * a slowdown in harddisk performance
 * system locks or instability
 * massive corruption of the filesystem (rare, but observed at least once)

Before use athcool, you must recognize these potential DANGERS.
Please use athcool AT YOUR OWN RISK.

athcool is supplied "as is". The author disclaims all warranties,
expressed or implied. The author and any other persons
assume no liability for damages, direct or consequential,
which may result from the use of athcool.

   Osamu Kayasono <jacobi@jcom.home.ne.jp>
   http://members.jcom.home.ne.jp/jacobi/linux/softwares.html


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2. Supported Chipsets
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VIA KX133
VIA KT133/KM133/KL133/KN133[A]
VIA KT266/333[A]
VIA KM266
VIA P/KN266
VIA KT400[A]/KM400/KT600
SiS 730/733
SiS 735/740/741/745/755
SiS 746[FX]/748
nVIDIA nForce
nVIDIA nForce2
AMD AMD-751/761
(AMD AMD-762)

* AMD-762 Chipset has not support HALT disconnect, 
  so Powersaving only enables when S1 or S3 state entered

see http://members.jcom.home.ne.jp/jacobi/linux/softwares.html
for more information


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3. Installation
--------------------------------------------
make
(become root if necessary)
make install

Good luck!

* required libraries and header files of pciutils, when building athcool.


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4. Usage
--------------------------------------------

/usr/sbin/athcool [options]

supported option:

 on    Enable power-saving mode
 off   Disable power-saving mode
 stat  Quely power-saving mode
 list  List supported chipsets

* install and use athcool, you need super user privilege.


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5. Related and Useful links
--------------------------------------------
 * CoolOn Project
	http://coolon.o-ya.net/

 * pciutils
	http://atrey.karlin.mff.cuni.cz/~mj/pciutils.shtml

 * Athlon Powersaving HOWTO
	http://www.daniel.nofftz.net/linux/Athlon-Powersaving-HOWTO.html

 * LVCool
	http://vcool.occludo.net/


