K8NS 939 fan problem

[-darkstar-]

I 've a problem with this MB, i2c works, i can see fan RPMS, CPU Temp etc but when i try to use pwm to slow fan i doesn't work... fan works for ever at 6000RPM... too noisy...
I've also tried to echo 0 on /sys/bus/i2sc/.../pwm1 but without success...

Can somebody help me?

I use lm_sensor 2.9.1 and vanilla kernel 2.6.12.3

[pgolik]

This is a hardware limitation of GA-K8NS boards. Only the "Ultra" versions have the smart fan capability, regular ones don't. Note that you don't have a "smart fan" option in the BIOS (even with the advanced settings enabled by Ctrl-F1).
The only solution if you want to keep your current cooler is to get a hadware fan controller, like the Zalman FanMate 2.
The stock AMD cooler is quite noisy, I suggest getting the Arctic Cooling Freezer 64 heatsink/fan. It's not expensive and it cools better at 2200 rpm (that's the maximum speed of this fan) than the AMD fan at 6000 rpm. Even at max. rpm it is barely audible, way quieter than the AMD fan. You could pair it with the Zalman controller and get a virtually noiseless solution.
If you are concerned about noise, another problem with this MB is the chipset (northbridge) fan, which makes an annoing noise. You could swap that for a fanless heatsink (I have a Zalman ZM-NB32K) provided that your case has sufficient airflow. The way GB laid it out, you have to make sure the new heatsink won't interfere with your AGP video card (if it does you can saw a bit of the heatsink off ).

Pawel