Xserve G5 fan control?

[Teenil]

Hi I'm using YDL 4.0.1 on Xserve G5 and I'm not sure if it has fan
control support for it.
The fan isn't working very loud but it doesn't speed up on high cpu usage.

The values in files:
	/sys/devices/temperature/cpu0_intake_fan_rpm
	/sys/devices/temperature/cpu0_exhaust_fan_rpm
are always exactly 4000, even when the value in 
	/sys/devices/temperature/cpu0_temperature
increases and the cpu usage is nearly 100%



In the kernel source installed with YDL I found this:
"TODO:
..
- Add RackMac3,1 support (XServe g5)"

So does anybody know if it's safe to use the kernel provided with YDL
4.0.1 or maybe i should patch it and recompile?