Handtweaking the CPU fan speed 2464

Linux can do almost anything. But it will never make Rui Maciel anything like smart... (For example, smart enough not to make stupid cracks that annoy people who can help him.)

... snip of accurate summary

... snip of accurate summary

Lmsensors, and related modules in the 2.6 kernel can handle those types... *if* the hardware is properly initialized to begin with, which may or may not be the case.

I've got a couple of Tyan Thunder K7 motherboards, manufactured about a year apart, that make an interesting example. The onboard hardware is there, but on one motherboard (made within a couple months of that board being released) it simply does not work. No fan speed control. It works fine of the board made about a year later.

However, in neither board is that hardware initialized, normally. If in the process of booting up the BIOS setup is accessed and the system monitor screen is viewed to see temperatures, voltages, and fan speeds, then bingo the hardware is enabled. Or at least part of it is. (I don't remember now if it actually enabled fan speed control too, or not.)

Regardless, to use the system monitor with lmsensors it was necessary to write a program that would initialize the hardware properly. After that, yes it was possible to control the cpu fans on the later version of the motherboard, but not on the early version.

buttuming the necessary kernel modules-options are in place, this should find the appropriate places to control fan speed with a 2.6 kernel:

findsys-devices -name 'pwm*'

I'm not sure what kind of variations there are with different hardware, or what is now available with the 2.4 kernels, and it has been years since I actually worked on that, so I can't really say just what one has to do to actually vary the speed of a fan or even how to butture that the kernel is configured to do so.

But yes, Linux *can* do it. (Of course!)

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