Gentoo Linux 2004.0 on a IBM Thinkpad T20

In this document I have put together some information of my configuration of Gentoo Linux on a IBM Thinkpad 2004.0.

Model: IBM Thinkpad T20 2647-44U 00/11
Motherboard FRU number 12P3360


suspend and hibernate

Suspend works with no problems. For hibernate have a look at this linuxfocus article:
To suspend use:
apm --suspend

During Kernel configuration you need to select the following for APM to work correctly:

Here is my complete kernel config file: config-2.4.29.txt


I use alsa 0.9.8 and it works well with the "Cirrus Logic CS 4614/22/24" but you have to specify the following in /etc/modules.d/alsa:
alias char-major-116 snd
alias char-major-14 soundcore
alias snd-card-0 snd-cs46xx
options snd-cs46xx thinkpad=1 index=0
alias sound-service-0-0 snd-mixer-oss
alias sound-service-0-1 snd-seq-oss
alias sound-service-0-3 snd-pcm-oss
alias sound-service-0-8 snd-seq-oss
alias sound-service-0-12 snd-pcm-oss
alias /dev/mixer snd-mixer-oss
alias /dev/dsp snd-pcm-oss
alias /dev/midi snd-seq-oss
options snd cards_limit=1

#Note the options line! Without it I would get the following
# cs46xx_lib.c:416: cs46xx: failure waiting for FIFO command to complete
# I have also PCI Bus Power Management disabled:
# From the ThinkPad setup (F1 after turning it on), choose 'config' and then
# 'power', scroll to the bottom and disable the 'PCI Bus Power Management'

Alsa has by default muted mixer settings. Unmute them with the command alsamixer (m to unmute) and then store the values with "alsactl store".


One of the hardest parts is the X11 configuration in gentoo as it does not provide any automatic configuraton utility. The advantage is that you really have control over you computer as a user but it takes time to configure things. Here is my XF86Config. Feel free to copy it.


The net-dialup/ltmodem driver will work with the
Xircom Mini-PCI V.90 56k Modem, PCI ID 115d:000c

Key hardware parameters

Here the output of lspci: lspci.html

T20 hardware maintenance manual

Power-on button problem. Can't switch on my good old T20

After 8 years the T20 showed suddenly the following symptom: Pressing the power-on button causes the HD LED to flash and the light on my USB mouse goes on for a moment but then nothing happens and everything is off again. If I wait for a while or try 10 or more times then it suddenly works. It starts normally no disk problem nothing wrong. Next day it worked with no problems a day later the same again: power-on failure.

This problem is known as "blink of death" (BoD) and there seems no clear explanation for it. Many T20/T21/T22/T23 owners get it one day.

First I replaced the CR2032 bios battery which had only 2.56V (a new one has 3.2V, measured with my DVM). It seemed that the problem was cured and the T20 worked for a week. After that same again. It's not possible to switch the T20 on. I checked the memory modules and removed the CD drive. Nothing. Finally I decided to open the T20:

There is a row of parallel 220uF tantalum capacitors close to the warm/hot CPU.

Tantalum or aluminium electrolytic capacitors age more quickly if they are heated. The voltage on the capacitors is 1.59V-1.63V. I soldered a new 220uF capacitor in parallel:

This cured the problem for a while and then it was back ;-(

After a longer investigation of the chips on the motherboard I think that I understand finally what is going on. The "blink of death" is caused by the MAX1632 chip in the T20. It is a step-down voltage regulator. The problem is that this chip has over and under voltage detection. It remembers that there was an under-voltage condition for either battery source or power supply source voltage and shuts then down. This is the "blink of death". It explains why sometimes you need to remove the battery and sometimes the power supply to be able to switch on. All conditions are cleared if you remove both power sources for several minutes.

This explains the symptom. The question is still what causes it. Why is there a temporary under voltage condition?

The only way to really solve the problem was to buy a new motherboard. After replacing the motherboard the problem is gone.

FAQ part

Which model is this t20?
IBM Thinkpad T20 2647-44U 00/11
PIII 700MHz, 256MB RAM, 14.1 XGA(1024x768) TFT LCD, 6X-2.3X DVD, Intel Mini PCI Combo card

How do I enter the bios
Press and hold F1 key while powering-up laptop. The T20 has a Phoenix BIOS.
You can enter the bios also with Press CTRL-ALT-F11 from DOS prompt.

© Guido Socher, guidosocher at,
Last update: Fri Nov 7 20:40:44 EST 2008
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