In the second case, if the license purports to involve useage, which (for example) the Apache Software Licenses do, a revocable license is a useage restriction.
The license does not restrict usage at all. The outside universe of patent law restricts usage. The contributors are granting a freedom that did not exist before on the premise that everyone benefiting from the work also grants that freedom. Without reciprocity, no such license will be given, and thus no grant is made. The only reason that the license even mentions usage is for the sake of granting permission to use. Termination of the patent license does not imply that the recipient cannot use the software. If they have a license via some other means, do not believe the patent is enforceable, or simply do not use the software in a way that would cause infringement, then even the loss of the specific patent grant in this license does not affect their rights. Nowhere does it say that the recipient cannot use the software without that patent license, nor does it imply that such a patent would be valid or enforceable. In short, it doesn't restrict freedom other than the new freedom that was given by the patent grant. ....Roy
