Installing and configuring Knoppix (Linux) on Thinkpad T42

I installed Knoppix 3.6 (Linux 2.6.11) on to the hard disk of my Thinkpad T42 (2378-FVU) in April 2005. I had Windows XP already installed on the hard disk, so I first used Partition Magic to create partitions for Linux, and then installed Linux with lilo as boot manager. In this page I describe some of the steps I took to configure my linux system to my liking.

Boot configuration

I placed "compact" in /etc/lilo.conf before the first image= line. Without this option loading the kernel at boot time takes more than 30 seconds.

This is my append= line in /etc/lilo.conf for the linux image:

  append="resume=/dev/hda5 ramdisk_size=100000 init=/etc/init apm=power-off nomce quiet lang=us desktop=kde screen=1400x1050 depth=32"

Choosing ACPI over APM

I set up the ACPI module to be loaded at boot time. For this I included apm=power-off in the append= line in /etc/lilo.conf. I chose ACPI over APM because only ACPI supports CPU frequency scaling (more on this later). If I wanted APM instead of ACPI I would have included acpi=off and apm=on in the append= line.

Unfortunately, however, I could not get suspend-to-RAM (Fn-F4) to work with ACPI (it worked right off the bat with APM). Basically, the system suffered a hard crash whenever I initiated suspend-to-RAM. A lot of web sites offer advice on how to fiddle with the boot parameters to make suspend-to-RAM work (e.g., using the s3bios boot parameter), but none of that helped me. In the end I decided to live without suspend-to-RAM, because I thought CPU frequency scaling was more valuable.

Suspend to disk

I could get suspend-to-disk to work easily with ACPI (in general suspend-to-disk involves fewer complications than suspend-to-RAM). I used the swsusp feature that is built-in to the 2.6.11 kernel. I did not use swsusp2 (which is supposed to be a big improvement over swsusp) because it requires downloading source code and compiling the kernel (it is not a part of the base 2.6.11 kernel). I use my swap partition /dev/hda5 for storing the memory image, by including resume=/dev/hda5 in lilo.conf. (This essentially means that if the previous time we suspended the machine rather than shutting it down then the next startup would use the saved image rather than do a startup from scratch.)

Caution is required while using swsusp; nothing on disk or anywhere else that is mounted at the time of suspension should be modified before resumption (otherwise we may lose those modifications after resumption, or worse still, crash the system). Therefore, we need to

To automate all this I wrote a script

Suspending to disk takes about 30 seconds. Resumption takes over a minute. This is not great, but it is still faster (and more convenient) than shutdown and startup.


Sound (using alsa) works fine after I resume from a suspend, but does not work after starting up from scratch. I have still not figured out why.

CPU frequency scaling

CPU Frequency scaling is supported by the Centrino architecture, and is critical to achieving good battery life and keeping the system cool. All three frequency scaling policies, namely "performance", "userspace", and "ondemand" worked for me. For the "userspace" policy I installed the freely downloadable powernowd userspace daemon, with its default configuration. It worked well. I finally settled on the "ondemand" policy, with its default configuration (the ondemand policy is built in to the kernel, and hence does not require anything to be installed). To make this policy available I added the following lines to /etc/modules-2.6.11:


To select the ondemand policy at boot time I created a script ondemand, and placed this script in the startup scripts directory (/etc/rc5.d).

Binding Thinkpad special buttons

I placed the following files in the directory /etc/acpi/events/: hibernate, lcd, powerbtn, lid. These scripts are written to be triggered by Fn-F12, Fn-F3, the power button, and lid closure events, respectively. These scripts do the following actions, respectively: suspend the computer to disk, toggle the LCD on and off, shutdown the computer, and do nothing. (The names of these scripts can be arbitrary.) For some reason the third and fourth scripts above did not work as desired. The above scripts use the following scripts which I placed in /etc/acpi/:,,, and For the script I downloaded the radeontool package (using apt-get).

To enable linux to recognize the Thinkpad buttons I placed the script ibmacpioptions in /etc/rc5.d. Also, I placed in a link in /etc/rc5.d to the system-supplied script /etc/init.d/acpid (acpid is the daemon that receives the button events and calls the scripts).