If you haven't already got a kernel with ACPI support, you have to enable it in
the kernel setup and then recompile the new kernel. You'll find the
ACPI-options under <menuchoice><guimenu>General Setup</guimenu><guimenu>Power Management Setup</guimenu><guimenuitem>ACPI</guimenuitem></menuchoice>. You must have at least the following options: <guimenuitem>ACPI Bus Manager</guimenuitem>, <guimenuitem>System</guimenuitem> and <guimenuitem>Processor.</guimenuitem>
Or for the new 2.4.22 Kernel: <menuchoice><guimenu>General Setup</guimenu><guimenu>ACPI Support</guimenu></menuchoice>. You must have at least the following option: <guimenuitem>Processor</guimenuitem>.
</para>
<para>
Some Chipsets also support a STPGNT if a HLT signal is detected. This Motherboards/Chipsets
don't need ACPI to be enabled! At the moment i look for feedback which Chipsets work without
ACPI and which need ACPI. Maybee you could test it on your Motherboard and send me a mail.
To use the command-line hack you normaly have to enable ACPI in the kernel, otherwise it is mentioned. No reboot is needed to enable the Powersaving. You could enable/disbale it from the command line with this commands:
Apply the patch: <command>cat $path-to-patch/amd_cool.diff | patch -p0</command>
</para>
</step>
<step>
<para>
<command>cd linux</command>
</para>
</step>
<step>
<para>
Make the new kernel
</para>
</step>
<step>
<para>
Reboot, and at the kernel boot-prompt, enter the statement <userinput> amd_disconnect=yes </userinput>. This is because there are known bugs within the Athlon processor, which could cause problems on several boards. You should test the patch, and if it works, you can append the statement <userinput> amd_disconnect=yes </userinput> to the file <filename>/etc/lilo.conf</filename>.
</para>
</step>
</procedure>
</sect2>
<sect2id="lvcool">
<title>The LVCool Solution</title>
<para>
<emphasis>LVCool</emphasis> is a small port of the Windows programm
<ulinkurl="http://vcool.occludo.net/">
VCool</ulink>. It only supports the KT133/133A and KX133 chipset and
Ok ... you use one of the described powersaving possibilitys and you want to verify, whether
it works. Here are two ways to check it:
</para>
<para>
If you have temperature controlled Fan on your CPU-Heatsink, you could check for the noise level of the Fan to see whether it works or not. After a few idle minutes you give the CPU somthing to do.
<procedure>
<title>I normaly do it like this:</title>
<step>
get superuser (root)
</step>
<step>
<command>cd /usr/src/linux</command>
</step>
<step>
and give the computer something to do: <command>while true; do make clean; make bzImage; done</command>
</step>
</procedure>
After about 20 or 30 seconds you should notice that the noise of the fan is getting louder while the fan is getting faster. Don't forget to end the while-loop after some time ( a few minutes) with STRG-C.
</para>
<para>
The same procedure as above works also with a monitoring program for the cpu-temperature (like lm-sensors or xmbmon).
<para>There are two known bugs in the Athlon/Duron processor. This is number
11 and number 14 in the <citetitle>AMD Athlon Processor Revision Guide</citetitle>. It looks like the Athlon XP is significantly less often affected by these bugs. So if you have an Athlon XP you are on the lucky side (like me).</para>
<para>There could be following problems (caused by the bugs):
<itemizedlist>
<listitem>
<para>skips during sound playback</para>
</listitem>
<listitem>
<para>skips and slowdown during video playback</para>
</listitem>
<listitem>
<para>slowdown of the ultra-DMA harddisk transfers</para>
<para>Sometimes a BIOS-update will help (it exists as a workaround for
bug 11, which could be done by the BIOS). But as far as I know there are
only a few boards out there which have this workaround in the BIOS.</para>
<para>For the Asus A7V133-C, it is known that the BIOS-option <option>PCI master read caching</option> will solve most problems when it is enabled. So look
at your BIOS to see whether it has such functionality.</para>
<para>It is also known that on some boards, the BIOS option <option>Delayed Transaction</option> solves some of the problems. You may want to give this option a try too.</para>
<para>WARNING: On boards with KT133A, this could enable the famous VIA-Southbridge bug!</para>
<para>From a Newsnet post, regarding Asus A7V:
<itemizedlist>
<listitem>
<para>without delayed transaction: sound-skips and TV-skips</para>
</listitem>
<listitem>
<para>with delayed transaction: no sound skips and only slight TV problems</para>
</listitem>
<listitem>
<para>with delayed transcation and master read caching: nearly no TV problems and no sound skips at all</para>
</listitem>
</itemizedlist>
</para>
<para>There are other causes for problems:
<itemizedlist>
<listitem>
<para>the PSU is not strong enough to handle the fluctuations in the power consumption of the processor/motherboard</para>
</listitem>
<listitem>
<para>some motherboard voltage-regulators could have the same problems like the PSU ;)</para>
