Comment by pdfernhout | Hacker News Reader

Comment by pdfernhout | Hacker News Reader

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The patent grant is (presumably) implied by the act of licensing under MIT in the absence of other specific restrictions (such as Facebook's PATENTS file as an explicit patent grant with one-sided limitations).

See for example: http://oss-watch.ac.uk/resources/fossandpatents "Some free and open source software licences also explicitly grant the patent rights necessary for the purposes of using, adapting and distributing the code, for example the Apache License v2, the GNU General Public License v3 and the Eclipse Public License. In some jurisdictions, including the UK, it is highly probable that even those free and open source software licences that do not explicitly grant patent rights do in fact provide them implicitly. After all, giving permission to perform a specific act strongly implies permission to perform the steps needed to do so. Thus the permission to redistribute the software granted by all free and open source licences - it can be argued - implies the granting of the right to make use of any of the licensor’s patents which would be infringed by the distribution of the code."

The big question about an implied patent license would be whether or not it is revocable.

In the specific cases of the BSD and MIT copyright licenses note that the licenses do not say that they are irrevocable. A license granted for no consideration is generally revocable unless it specifically says that it is not.

There are substitutes for consideration. It is an open question as far as I know whether or not those apply in the case of free software and make licenses like MIT and BSD irrevocable.

If you use BSD or MIT licensed patented software that does not come with an explicit patent grant, you'll have to deal with these arguments if the patent owner decides to go to court:

1. There is no implied patent license,

2. If there is an implied patent license it is revocable and they revoked yours,

3. The copyright license is revocable, they revoked yours, and that implicitly revokes the implied patent license (even if it is irrevocable normally).

It's so much safer to try to stick to licenses that say they are irrevocable and include an explicit patent grant.

"It's so much safer to try to stick to licenses that say they are irrevocable and include an explicit patent grant."

Sadly, although Facebook includes an explicit patent grant, it does not claim to be irrevocable. They even list one specific case where it can be revoked.

Nice if you are in UK, but a very small % of tech companies is in UK.

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