Comment 27 for bug 77370

In my case, should I echo the fan states off and back on, the fan[i]'s turn on according to the current trip points. For example, having active[2] 62 C, and the computer temperature at the time of issuing the echo would be 65, FAN3 (50C) and FAN2 (62C) are set on. FAN1 and FAN0 stay off regardless of the command.

The ACPI event system seems to be totally dead after STR (acpi_listen gives no thermal etc. events any more), so the fans will not turn off without manual re-echo of "off and on" OR without enabling polling!

However, even with the polling enabled nothing is adjusting the trip points, resulting in a fan turning constantly on and off as the temperature bounces +-2C around the default trip point.

Doing as Jesse suggested is not an option at least for me, as the fan does not react to temperature changes it might result in serious overheating (what if critical temperature event is not received?).

Having only FAN3 (or FAN4 in Jesse's case?) on is the slowest spinning speed of the fan. This is enough to keep the system cool on light load but no more.