One option is badly named. "none" implies off, it would be better as "bios", or "default".
Please fix before it's in kernel and can't be changed
Hey, I understand your complain but not matter what name I find, they are all confusing in some way. In the case of "bios" or "default", it doesn't express that you leave it in this state.
With FAN_CTRL_NONE, it really means that there is no control and thus, the fan is left untouched. For now, this mode is the default, but starting from next kernel, I will push for auto fan management as a default.