terça-feira, 20 de novembro de 2012

Thinkpad T410+Ubuntu 12.10+scientific simulations=reboot

Sometimes you need to push your laptop a little more... 
If you are a Linux user, maybe the relation fan speed x temperature x frequency  of the cores isn't good enought. In fact, linux isn't doing a good job for my laptop -- the computer keeps overheating and rebooting on every single computational experiment. The following procedure fixed my problem. 

Disabling the thermal managment of the linux kernel:
1) Edit /etc/default/grub
2) replace the line GRUB_CMDLINE_LINUX_DEFAULT=... to
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash thermal.off=1"
3) run update-grub



quinta-feira, 29 de março de 2012

Fixing my lenovo T61

My lenovo T61 died a couple of months ago when i was trying to play the game "dead island". The same thing happened to my friend's R61: Scrambled screen on start up. When looking for more information, I found that it's a common problem related to all notebooks with the NVIDIA 140m GPU.

Lots of people are having the same problem (http://forums.lenovo.com/t5/T61-and-prior-T-series-ThinkPad/T61-Nvidia-Quadro-NVS-140M-garbled-display-problem/m-p/46469). I did the reflow procedure, but, after 2 months, the problem returns. In fact, the g86-740-a2 chip is bad, and hot as hell. I don't think I'll buy another nvidia product again.

In order to repair my laptop, I bought a cheap motherboard (with Intel 3100 graphics, of course) with bios password. Now, my problem is to remove the bios password from my new motherboard.

First, i replaced the BIOS chip on my new board with the BIOS chip on my faulty motherboard. Unfortunately, it didn't work. The error message was "0192 System Security. Embedded Security hardware tamper detected.". There is no way to remove this message by configuration or software. The only known way to fix it is by replacing the motherboard (http://support.lenovo.com/en_US/detail.page?LegacyDocID=migr-42321).

It means that the BIOS chip is somehow designed to be attached to only one motherboard. In fact, there is a security chip (p24s08) that checks if the bios chip is the right one. Then, I replaced the security chip on my new board with the security chip on my broken board. It worked like a charm.