Comment 46 for bug 370173

James - http://www.thinkwiki.org/wiki/How_to_control_fan_speed

I'm using a T61

I will repeat what I posted earlier, the Lenovo T61 fan is controlled by the thinkpad-acpi module. There is no question on this. It IS a kernel module. It is called thinkpad-acpi - in the following you will find a successful method to override control of the fan so you can choose the speed or disengage control completely (so it runs full speed). Also note that fan speed control and cpu controls are for power saving only. There is no issue with running your fan at full speed (some bios allow you to override this on ac power - HP does) - and there should be no issue running your cpu at its full speed either. You aren't "over clocking" anything. The only reason for controlling these things in this context is to save battery life. On AC I'm not worried about battery, so letting the fan run full speed is not an issue for me.

For more info, see the following: http://www.thinkwiki.org/wiki/How_to_control_fan_speed - this is specific to ThinkPads.

You can monitor your fan speed from the thinkpad-acpi module: cat /proc/acpi/ibm/fan (check path under /proc for your laptop)

You can adjust the fan speed to stay on at full speed by executing the following command as root: echo level disengaged > /proc/acpi/ibm/fan

(you will need to uninstall any other fan control applications or scripts you may have tried, including tpfand)

With the fan running between 4000-5000 rpm cooling is not a problem.

When fan control is engaged in the thinkpad-acpi module, the fan spins *only* between 0 and about 3000 rpm and takes quite a while to kick in - usually too late. With the control disengaged the fan runs at full speed. (but is not noisy)

For more info, see the following: http://www.thinkwiki.org/wiki/How_to_control_fan_speed

The issue is that the fan does not spin up soon enough or fast enough when the processor is running at full speed.

THAT is the bug.