First off, if you didn't read already, see my article earlier today: Trying Out The Jetson TK1, NVIDIA's High-End Tegra K1 Board. My Jetson TK1 arrived this morning and I've spent most of the day playing around with (and getting benchmarks ready) for this Tegra K1 platform with four ARM Cortex-A15 cores (plus a fifth companion core) and a Kepler GPU with 192 CUDA cores.
As mentioned in the earlier article, by default the system just boots up to a VT console -- with working KMS. From the console when I would attempt to run startx with the stock packages, it appears the system would just hang. However, I've since received clarifications from NVIDIA that there's a simple setup procedure for using the binary graphics driver. With the Tegra K1 Ubuntu 14.04 file-system, located within /home/ubuntu/NVIDIA-INSTALLER is the binary graphics driver installer. This NVIDIA-INSTALLER wasn't covered in the quick start guide and the NVIDIA developers are still working to get up all the TK1 documentation on their web-site.
Anyhow, once within the ~/NVIDIA-INSTALLER directory, simply run sudo ./installer.sh. This will install the NVIDIA graphics driver automatically and you can then reboot. This NVIDIA installer package isn't the same as their mainline Linux graphics driver, even though the Tegra K1 is using a Kepler-based GPU and their mainline driver package was made ARM compatible recently. This NVIDIA driver package ships a driver labeled Release 19.2.
After rebooting the system, the Unity desktop fired up and the NVIDIA binary blob was properly loaded and exposing full OpenGL 4.4 support on ARM!
Another quick tip is that the NVIDIA Ubuntu installation disables most of the Ubuntu package repositories within /etc/apt/sources.list, so you'll want to enable most of them to get access to the full Ubuntu package universe.
Stay tuned for the first of the Phoronix benchmarks of the NVIDIA Jetson TK1 board in the next day or two.