X86 chip manufacturers should probably be a little bit worried at this point, considering that Microsoft has also decided to do a full windows port to ARM. Of course, Linux has been running beautifully on ARM for almost two decades already.
Don't be fooled, Nvidia's ARM team is not only aiming at the netbook / laptop market - they're setting their crosshairs on the desktop market as well, as indicated by their roadmap.
PS: If you are reading this, and you were present at a certain meeting with me not too long ago where we were talking about buying an ARM architecture license, then I hope you are hearing this message loud and clear. My honest opinion is that you need to act now or suffer tremendously in sales.