Comment 41 for bug 213818

I've been trying various of the /proc/acpi/ibm/fan commands, but find that none of them have any affect on the fan speed, except disable, which reports it as being zero, but doesn't the laptop seem otherwise unaffected. Disengaged mode also makes no difference.

Might this be a confusion between the old /proc/acpi/ibm interface and the newer /sys/bus/platform/ one?

Given that these do not actually change the fan speed, there is still no real workaround. One useful thing I found is to temporarily stop active processes and wait for the lapot to cool down: sudo kill -STOP process-id; but this is very far from satisfactory. For example, upgrading from 8.10 to 9.04 causes an overheat...