Athlon Powersaving HOWTO

Daniel Nofftz

<daniel@nofftz.net.NOSPAM>

2007-05-13

Revision History
Revision 1.2.1	2007-05-13	Revised by: dn
corrections to the new copyright statement, corrections to the disclaimer
Revision 1.2	2007-05-10	Revised by: dn
coolrun added, new URL for (brazilian) Portuguese Version, License Change (GNU FDL to GNU GPL), some minor accessibility related changes
Revision 1.1.12	2006-04-06	Revised by: dn
typos corrected
Revision 1.1.11	2005-03-05	Revised by: dn
SiS741 was false ... now it should be right. some command-line hacks modified.

How to enable the power-saving functionality of the Athlon/Duron/AthlonXP processor on some motherboards/chipsets. This is usefull for saving Power and lowering the Temperature of the CPU and the System. (It also will reduce noise if you use temperature controlled fans in your case/on your cpu heatsink).

Table of Contents

1. Introduction

1.1. Basics on the Athlon Power Saving Mode
1.2. Copyright and License
1.3. Disclaimer
1.4. Feedback/Questions/Support
1.5. New Versions of this Document

2. The Different Approaches

2.1. The Command-line Hack (recommended)
2.2. The coolrun shellscript (recommended)
2.3. The Athcool Program (recommended)
2.4. BIOS updates
2.5. Kernel Patches
2.6. The LVCool Solution
2.7. The FVCool Program
2.8. AMD 760MP Powersaving

3. What Else?

3.1. How to test whether it works
3.2. Known Bugs/Problems
3.3. Fix for sound skips and other problems
3.4. Another Fix for sound skips and other problems (on some Via-Chipsets)
3.5. ToDo
3.6. Translations

1. Introduction

1.1. Basics on the Athlon Power Saving Mode

The HLT signal which is used by the normal idle-loop of the Linux kernel doesn't normaly bring any significant power-saving on processors of the Athlon/Duron family (hereafter referred to as Athlon processors). To get real power-saving on an Athlon processor, you have to put the processor in the STPGNT-Mode (Stop Grant Mode). In this mode, the processor is disconnected from the front-side bus (FSB), and can turn off parts of the CPU as well as reduce the clock to save power.

Some modern Motherboards/Chipsets also support a Function to make a STPGNT when a HLT signal is detected.

1.2. Copyright and License

This work is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License, version 2, as published by the Free Software Foundation.

A copy of the license is available at http://www.daniel.nofftz.net/linux/gpl_v2.txt.

Linux is a registered trademark of Linus Torvalds.

1.3. Disclaimer

This work is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

All copyrights are held by their respective owners, unless specifically noted otherwise. Use of a term in this document should not be regarded as affecting the validity of any trademark or service mark. Naming of particular products or brands should not be seen as endorsements.

1.4. Feedback/Questions/Support

Feedback is most essential for this document. New solutions for new chipsets are especially needed, as are comments, whether the provided solutions work or don't work. Also please report spelling errors if you find them, cause i am no native english speaker. Send your additions, comments, criticisms and questions to the following email address: <daniel@nofftz.net.NOSPAM>. You can email me in German or English!

If you want to support me, you could donate through Paypal (to the same email-adress) or send me some new Hardware to play with. ;)

1.5. New Versions of this Document

The newest version of this HOWTO will always first be made available at: http://www.daniel.nofftz.net/linux/

The sourcecode of this HOWTO is hosted at the Linux Documentation Project or can be requested from me.