Linux Desktop Hacks

Control Your Power with ACPI #96

Chapter 11, Hardware

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HACK

patch, so be sure to check for one at http://acpi.sourceforge.net. If your distri-

bution has already patched your kernel, you might have difficulty applying a

second patch for ACPI. Read /usr/src/kernel-source-<version>/README to

see if your kernel has already been patched.

If you are already running a kernel with ACPI support, you can check the

ACPI revision date with the following command:

foo@bar:~$ cat /proc/acpi/info

This might give you detailed list or only a version number. You are looking

for the line that starts with

version:.

Load Related Modules

The next step is to check to see that each ACPI module is loaded after your

machine boots. You can do this with the

lsmod command. You are looking

for the following options:

button, battery, fan, ac, thermal, and processor.If

you chose

Y instead of M (modules) when you compiled your kernel, you will

not see this list, because the components were compiled into the kernel

itself. Otherwise, the output should look similar to this:

Module Size Used by

button 2420 0 (unused)

battery 5960 0 (unused)

ac 1832 0 (unused)

fan 1608 0 (unused)

thermal 6664 0 (unused)

processor 8664 0 [thermal]

If you compiled ACPI support as modules and you do not see the ACPI

modules listed, you need to load the modules by hand. The modules should

be in /lib/modules/<kernel-version>/kernel/drivers/acpi/.

To prevent ...