Recent NVIDIA Linux driver releases support the G92-based GeForce GTX 280M with the 2D/3D/VDPAU support and other expected features. PowerMizer does work with this notebook GPU under Linux, though NVIDIA Hybrid Power is one of the features that is still lacking from their proprietary Linux driver. When it comes to open-source support for this notebook, the xf86-video-nv driver will work for mode-setting and 2D support, but that is about the extent of the support. The Nouveau support is still very experimental especially on the recent GeForce 9 and 200 series.
The PowerMizer performance levels for the GTX 280M include 200/100MHz, 275/301MHz, 383/301MHz, and 583/800MHz.