NVIDIA's Alexandre Courbot pushed out the signed firmware this morning for the GM200/GM204 hardware and the related Nouveau code. He began his message with, "I know, it's about f**king time and I apologize for the time it took us to finally put this together. m(__)m"
This signed firmware fiasco has held up the open-source Linux driver from supporting hardware acceleration on NVIDIA's latest generation GPUs. We're now just months away from Pascal while Maxwell can only now move on with open-source 3D, but at least NVIDIA's official, proprietary Linux driver continues working great. This change in requiring the firmware to be signed is what led Nouveau developers to call the Maxwell GPUs "VERY Open-Source Unfriendly".
There is now the signed firmware blobs for the GM200 and GM204, which is currently in a separate Git repository but will be merged into linux-firmware once all the DRM driver code is into shape.
There is also the "secboot" code for Nouveau that provides the pieces to the open-source kernel driver for being able to load the signed firmware.
Before getting too excited, there isn't yet working open-source 3D for the GTX 900 series but some changes to Mesa are needed for the NVC0 Gallium3D driver. However, Courbot says that the necessary enablement shouldn't be much to get it working, "the changes for basic support are rather modest, and hopefully this pre-release will be enough to enable patches to land in Mesa."
He's hoping that in conjunction with the Nouveau developers they will be able to get all of this code prepped and landed in the Linux 4.6 kernel cycle. Find out more via this Nouveau message.