Thursday, June 5, 2008

Controlling the fan on a Dell

A couple of days ago the fan on my Dell Latitude D410 (running Ubuntu Hardy) started behaving strangely.

Once the fan started up it would stay on. Very annoying.

I did the usual checking for runaway processes but there were no such problems.

So I then checked the CPU temperature:


cat /proc/acpi/thermal_zone/THM/temperature


Next I discovered that the sensors screenlet can be used to display the temperature.

Watching this the cpu temperature steadily rose, the fan clicked in, the cpu cooled but the fan never shuts down.

A bit of googling looking for others with the same laptop and this problem came up with the dellfand project.

This is a simple daemon to control the fan on Dells. Works great, and now I can control just what temperatures the fan clicks in, goes into high speed and shuts off.

I'm still puzzled what broke/changed the other day, but at least for now I can control the problem.