Re: nvidia reactions to Greg Kroah-Hartman's announcement.
The "All that is needed is some kind of specification that describes how your device works" part may be practical for some simple USB widget, or maybe something as complex as a network card.
I fail to see how even such a description, for a video card, would result in a free driver within reasonable amount of time.
The Nvidia driver module is 7.2 megabytes of binary code. While part of that is probably explained by a monolytic structure with similar code for many different chipsets, there really is a lot to write, debug and support.
For example, the Intel-supported driver for modern ethernet chipsets (with a lot of advanced features) is only 117 kilobytes, or 62 times smaller.