Man Linux: Main Page and Category List


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


       athcool command


       athcool  is  a  program  that  controls  the  power-saving  mode on AMD
       Athlon/Duron CPUs.  The parameter command is one of:

       on     Enable power-saving mode.

       off    Disable power-saving mode.

       stat   Query power-saving mode.

       list   List supported chipsets.


       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.

       Depending on your  motherboard  and/or  hardware  components,  enabling
       power-saving mode may cause:

              * noisy or distorted sound playback,

              * a slowdown in disk performance,

              * system freezes 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.


       Copyright (C) 2002-2004 Osamu Kayasono <>

       This manual page was written by Nicolas Boullis  <>.
       And  many  users  reported  to me it works (or not).  Thanks to all who
       contributed to athcool.

       This program is free software; you can redistribute it and/or modify it
       under  the  terms of the GNU General Public License as published by the
       Free Software Foundation; either version 2 of the License, or (at  your
       option) any later version.

       This  program  is  distributed  in the hope that it will be useful, but
       WITHOUT  ANY  WARRANTY;  without   even   the   implied   warranty   of
       General Public License for more details.

       You should have received a copy of the GNU General Public License along
       with this program; if not, write to the Free Software Foundation, Inc.,
       675 Mass Ave, Cambridge, MA 02139, USA.

       On Debian systems, the complete text of the GNU General Public  License
       can be found in /usr/share/common-licenses/GPL.


       For more information about power-saving with Athlon/Duron CPUs, see the
       Athlon-Powersaving-HOWTO at

                                 Jul. 27, 2004