Among other functionality, the open-source Nouveau driver now has support for fan control modes. The two modes now exposed for the Nouveau driver is NONE and MANUAL. The NONE mode means that the Nouveau driver never touches the fan control mode while MANUAL allows a user-defined fan speed.
This is still fairly rudimentary fan control support, but at least its moving ahead. Up to this point those using the Nouveau driver but with graphics cards not having a PWM-based fan for dynamically adjusting the fan speed based upon load/temperature, using this reverse-engineered Nouveau driver can often be quite noisy.
The commit for this support can be found here in the Nouveau DRM tree, which will hopefully be hitting the mainline Linux 3.7 kernel. Several other Nouveau commits also landed today after the Nouveau work was re-based.