Fan speed control not accurate

[sksbir]

Hi
it would be nice to control fan speed in a more accurate way:
For example on AS3102T:
- auto : about 700rpm, silent but leaves internal disk too hot : 43°C
- medium : about 2300rpm , ok for disk ( 33°C ) but too noisy.
- high : not tested.

since 'auto' leaves internal components too hot, it would be nice to have ability to choose 100rpm steps from 800 to 3000