Asus A6T, defective DSDT

This document describes my troubles and some solutions for my laptop, in this case an Asus A6T. The document has been created to show Asus what the faults are, and how many people it affects. If you have the same laptop or a similar model and experience some of the same problems, please contact me.


I bought the laptop from a Danish retailer. A few days later I discovered problems with the DSDT and upgraded BIOS from version 601 to version 701. This did not solve my problems. The solution was to disassemble the DSDT and fix the programming errors in it. Since then the laptop has run fine. My efforts with the DSDT can be found here


I buy myself a hardware upgrade. 1GB extra RAM. This involves a lot of trouble. I contact Asus support and they want me to take the laptop in for a repair, but since this is DSDT errors, a hardware repair is not the correct solution. I fill out a form on some Asus RMA page, a form that cannot contain special characters like ":,;!?/". Really hard to use proper language or refer to other webpages without those, so I am forced to put up a homepage and refer to it instead.


I write the following error report to Asus support:

Asus A6T, defective DSDT

This report should be comprehensive enough to explain that the problem is not related to the hardware, but rather the software controlling the ACPI parts of the computer in question.

First of all, it is that the DSDT provided by the BIOS is defective. This is related to a couple of things. Specifically the fan runs until the DSDT is fixed. There is a lot of talk about these problems on the wiki page provided by gentoo-wiki. The information has been split into two parts, discussion and installation manual. The wiki is down, so the links above point to google's cache instead, same information is provided there.

The problem I am contacting you about is specifically about the symptoms I get when 2GB RAM is installed. Symptoms are: CPU is no longer able to change speeds, the battery does not report its status, system does not power off when shut down. All these are related to ACPI, more specific, to DSDT.

When the system is started with one 1GB RAM it runs as expected, this happens with any of the two RAM modules. When the system runs with both sticks it runs and works, but has symptoms mentioned above, so this is not due to defective RAM modules. Both modules has been tested individually and together with memtest86 software. memtest86 does not report any errors.

While looking through the logs i noticed a lot of differences. This is the log when running on 1GB RAM, this is when running with 2GB RAM. Notice all the errors reported by ACPI.
Another important thing to mention is that the system runs on BIOS version 702, and this has been tested on BIOS version 701 too.
It seems your way of doing things is to turn the PC in for repair, even though I explained over the phone that this is related to all computers of this model, and that it is not a hardware issue, but rather middleware. A BIOS upgrade (with a fixed DSDT) would be helpful, but none is avalable at the moment. If you decide to take this laptop in for a repair, I must tell you that the technician most likely will call the system flawless, so please call and advice before you make an attempt at a hardware repair.

The laptop you recieve is encrypted, so you will not be able to run the operating system on it. You will have to do tests from a livecd or contact me.

How do we solve this issue?

yours sincerely

Kristian Kallenberg


I receive the following mail from asus:
Dear Kalle,

A new BIOS was released this month, with some modifications to DSDT code, BIOS 0705

Does it solve your problem?

After some searching I am unable to find the BIOS upgrade and write the following back to asus:
Citat af "Shandramohan Vadiveal" :

> Dear Kalle,
> A new BIOS was released this month, with some modifications to DSDT code,
> BIOS 0705

If you would be so helpful to provide a direct URL, or attach the file  
to an email, I will try it. I am unable to find it on your website.

> Does it solve your problem?

I do not know yet, since i cannot find the file.

I am looking forward to receiving the file and to test it out

Yours Sincerely

Kristian Kallenberg


I use some extra time and finally finds the BIOS upgrade and install it, but it does not solve my issues. It does not even solve the issues it is supposed to solve, fan control still does not work properly. At this point my own DSDT is still better!


I receive an email from Asus support with an URL to the BIOS upgrade. I reply to this the same day I receive it:
Citat af "Shandramohan Vadiveal" :

> Dear Kristian,
> A direct link to the BIOS:

OK, now i have tested the proposed update, it does not do the job! It even does NOT fix what it is supposed to fix. At this point my own DSDT is better than the one you provide. Please advice!

Yours Sincerely

Kristian Kallenberg


Today I recived a memory module containing 512MB of RAM. This module has been tested in the laptop too, but it produces the same results, as when the laptop has 2GB memory installed. So this did not get me any closer to a solution. The dmesg for 1.5GB RAM can be found here. dmesg-1.5GB.
Please advice.
Yours sincerely

Kristian Kallenberg


I once again call Asus support to find out what to do. The clerk asks me to send in the laptop, but i convince him to read this document. He explains that the person who earlier handled the case is on vacation. He promises me that he will look into the case and send me an email as soon as he knows someting.


My laptop has begun to start with a blank screen. This means that no text is displayed in textmode. The screen powers on, and the backlight is seen. BIOS output, e.g. POST is not shown either. System loads initrd from lilo and after encryption key has been entered the system boots. Most times the X system makes the screen display something. Some times even X is not displayed. When the system has booted into this state with a blank screen, i can log in remotely, and i can even use the system locally and play a movie, of course only audio is heard.

I believe this is due to the recent BIOS upgrade, i'll downgrade the BIOS as soon as possible the find out if this was the issue, and provide dmesg infor for 1gb, 1.5gb and 5gb RAM


Today i tested the system with 1.5 GB of RAM. Iget get the same symptoms as earlier. 1gb RAM and 1.5gb RAM. So the conclusion is that this BIOS version does NOT solve the issue. However i am unable to downgrade to BIOS version 705. This is because the Windows flash program does not allow to install an earlier version of the firmware. Also installing via DOS is now impossible since the system no longer displayes textmode. I am unable to view anything on the screen while in textmode. This applies to the BIOS POST screen too. So making a BIOS reset will be hard to do too.

Today i remembered that i recently installed newest windows drivers for the system. This could be the reason for the problem rather than the BIOS upgrade being the problem. I'll try to find out how to reset the CMOS. There is just no CMOS jumper in the RAM compartment of the laptop.

There is no reset button in the RAM compartment, but rather one that can be pressed through a hole on the backside. The button seems to just power off the system. Putting on an external monitor gives me textmode though, but pressing F2 for bios freeses the system. There is no output from POST or BIOS either. What i need now is to reset the CMOS. Please advice.

I once again call asus support. This time I am told that there is no longer made any driver upgrades for the laptop. This includes BIOS upgrades. Which effectivily means, that the problem will never be solved. I ask asus for the specifications for the machine, so i have a chance of making a DSDT myself. They will try and find out, if the specifications are available.
At this point I must advice against bying asus products.


Nothing really happens and i really want my laptop to function, so i once again call Asus support. I did start the initial case within the 2 year warranty period, so I expect them to take the laptop in for repair.
After talking to an Asus employee over phone, he promisis me, to talk to his supervisor and get back to me about making an RMA case. I was promised that i would get an aswer within the next day.

Serial number for my laptop is: 6an0ac000830.


I once again call Asus support, speaking to "dan", who i can refer to only as "dan". He is first unwilling to read this page, but after i explain to him that it contains the whole case, and all what has happened, he reads it. He also claims that there is no case for my laptop in Asus's systems. Somehow they have lost track of my earlier calls.

Dan claims that he is not able to make the decision about getting my laptop repaired on his own, and i tell him that i want to speak to someone who can make that decision. He wants to call me back, but i'm not falling for it this time. He finds the guy i talked to last time, a "stefan", and promises me that stefan will call me back within the day.

He also tells me that stefan is unable to decide wether my laptop can go for repair or not. So i once again tell him that i need to talk to someone that can make decisions.

These people, that are making decisions are having a meeting, he promises they will call me. I tell dan, that if they do not call me today, or tomorrow, i will call him back the day after. I really hope asus got the message this time.
This experience was gained by Kristian Kallenberg. If you experienced something similar, please contact me.

People this affects:

Kristian Kallenberg,
Virgil Otelaru,
Tom Mueller-Heumann
Raphael Pereira
Michael Dominov