Problem with fan noise
Information about the fan noise problem in Thinkpad models from 2003/2004.
Problem description
There seem to be two different occurances of the problem (or two different problems).
acceleration problem:
The Thinkpad Fan accelerates in regular intervals, making an annoying noise.
always on problem:
The Fan is always on, even though the processor is rather cool.
Affected Models
acceleration problem:
- Thinkpad T40, T40p, T41, T42(?)
always on problem:
- Thinkpad T40, T40p, T41, T41p, T42, T42p, T43
- Thinkpad R50, R50p, R51, R51p
- Thinkpad A31p
- Thinkpad 770Z
Affected Operating Systems
acceleration problem:
- Linux, all flavours
always on problem:
- Linux, all flavours
- FreeBSD 5.3
Status
acceleration problem:
IBM released an update to the embedded controller program that seems to at least partially solve this problem:
Version 3.03 - 1RHT70WW NOTE: This version of Embedded Controller Program will only work with BIOS Version 3.06f (or higher). * (Fix) Reduced Fan noise in some models.
The update can be found here: http://www-306.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-50279
always on problem:
The problem is yet unsolved.
IBM made a statement regarding this on their homepage: http://www-307.ibm.com/pc/support/site.wss/MIGR-56504.html
It seems that it's a feature of centrino - http://mailman.linux-thinkpad.org/pipermail/linux-thinkpad/2004-September/019737.html Perhaps it's fixable by adding the fans and temps to the dsdt?
Solutions
acceleration problem:
Replacing the fan
Some people reported that they replaced the original fan against one of a similar notebook without the problem has worked for them, i.e. changing a T41s fan against one from a T41p.
BIOS upgrade
You can try upgrading your embedded controller program to version 3.03 or newer.
The update can be found here: http://www-306.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-50279
always on problem:
It seems like for some people a combination of enabling dynamic frequency scaling and using the most recent radeon drivers (from xorg 6.8.x) with the DynamicClocks option enabled helped lowing the fan rotation and hence making it more quiet.
Also the fglrx driver from ATI is said to show the same effect when used together with dynamic frequency scaling.
On a 770Z the fan can be fully controlled through ACPI. Thermal Zone THM5 (possibly the battery/charging circuit, definitely warmer when using 5v PCMCIA cards and AC) triggers it to turn on and not ever off by design. Can be solved by a custom DSDT, which also makes use of the variable-speed features of the fan (will release this once I've finished tweaking and testing it).
