Not so difficult really

It appears that FOSS may need to defend itself against patent attacks from litigious closed source companies (no names mentioned). Prior art isn't in itself a perfect defence, for a lot of reasons. The patent office will probably miss it when granting the patent, there is a legal presumption in favour of the patent holder, etc.

The way the big boys play this game is to hold an arsenal of patents that they can wave threateningly at each other if any of them gets a bit uppity. Having good lawyers also helps.

So the challenge is to invent some patent equivalent of an open-source licence. That is, some way of obtaining a patent that can be used to defend open-source by taking legal action against closed-source software that uses the idea.

Red Hat have got that far. But the key bit still missing is to ensure that all open-source software can still use the idea without EVER coming into conflict with the patent holder. I think this just needs the patent holder to issue a non-revocable licence for the use of the technology in open-source software.

Obviously the exact form of words is important, but i don't see this as very different to the way open-source software is itself licensed at present. Basically, if you adhere to the FOSS principles, you can incorporate open-source software into your own project and the licence you are granted to do this can't be revoked. Patents could work in exactly the same way. If you obey the rules, you get a free licence to use the patent that can't be revoked.

Of course, the patent-holder could still license the patent to closed-source companies, at a fee. Problem solved.