Acceptable patent license for free software?

[Simon Josefsson]

MJ Ray <mjr-uWYXIsyQkeEe6eUIopPxIg at public.gmane.org> writes:

> Simon Josefsson <simon-RTwAkxXyIg6Ei8DpZVb4nw at public.gmane.org> wrote:
>> Hi!  I'm writing guidelines for IETF document authors on how to achieve
>> free software compatible copyright and patent licenses [1].  [...]
>> [1] http://josefsson.org/bcp78broken/draft-josefsson-free-standards-howto.html
>> Does anyone have some references to any patent license that have been
>> deemed acceptable to some free software projects?
>>
>> Going further, is there some kind of patent license that free software
>> would _prefer_ (as opposed to just _accept_)?
>
> Thank you for writing guidelines.  I cannot answer the above two
> questions.  I am mostly ignorant of software patent licensing because
> I believe pure software is a sequence of mathematical expressions
> which cannot be invented, only discovered.

I tend to agree with you, which would argue for changing the (software)
patent system.  Meanwhile, it may be useful to work within the system to
be able to arrive at ideas which are the second best thing.

>> To give a concrete example of what I'm thinking of:
>>
>> There is one patent license in <https://datatracker.ietf.org/ipr/942/>:
>>
>>   Subject to the terms and conditions of this License, Google hereby
>>   grants to You a perpetual, worldwide, non-exclusive, no-charge,
>>   royalty-free, irrevocable (except as stated in this License) patent
>>   license for patents necessarily infringed by implementation (in whole
>>   or in part) of this specification. If You institute patent litigation
>>   against any entity (including a cross-claim or counterclaim in a
>>   lawsuit) alleging that the implementation of the specification
>>   constitutes direct or contributory patent infringement, then any
>>   patent licenses for the specification granted to You under this
>>   License shall terminate as of the date such litigation is filed.
>>
>> This patent license is a reciprocal license, but is fairly limited in
>> scope.
>>
>> Would that be acceptable to free software projects?
>
> No, I think - to call it free software, I would want to be able to use
> the patent-covered software "for any purpose" and not just
> "implementation of this specification" like in the above.  Compare
> with http://www.fsf.org/licensing/essays/free-sw.html

I agree that it would be better if the license said "for any purpose".

I wonder if that is compatible with the current patent system.  Isn't
there some requirement that you need to protect infringement on your
patent somehow?  Or is that FUD, and that it is possible to license away
rights to implement techniques under a patent "for any purpose" to
anyone?

In particular, what I'd like to understand is whether a patent
reciprocal license is in general incompatible with free software.  Would
a license like this like this be unacceptable?

   Subject to the terms and conditions of this License, X hereby grants
   to You a perpetual, worldwide, non-exlusive, no-charge, royalty-free,
   irrevocable (except as stated in this License) patent license on
   patent X to be used for any purpose.  If You institute patent
   litigation against any entity (including a cross-claim or
   counterclaim in a lawsuit) alleging either direct or contributory
   patent infringement, then any patent licenses granted to You under
   this License shall terminate as of the date such litigation is filed.

There is a problem in writing guidelines if nobody sets an example by
using some (to be determined) free software friendly patent license.  If
we can't find an example that has been used in the industry, the
document should say that.  The document could include an illustrative
example of a free software compatible patent license (such as the one
above, if that is OK) in the hope that someone will use it in the
future.

My hope is that the state of affairs is more evolved than I am aware of,
and that there actually are free software compatible patent licenses in
use somewhere.

I've read RedHat's patent license, and it seems restricted to OSI
approved licensed implementations only.  That seems like another
restriction that would violate FSF's freedom 3?  I may be wrong though.

/Simon

[1] http://www.redhat.com/legal/patent_policy.html