About libinput license.

[Peter Hutterer]

On Fri, Dec 20, 2019 at 12:46:00PM +0900, Yoshiaki Seko wrote:
> Dear libinput Developers
> 
> I'm Seko.I have a question.
> 
> We want to use libinput.
> I see your  HP and I think libinput is MIT License.
> https://wayland.freedesktop.org/libinput/doc/latest/faqs.html#is-libinput-gpl-licensed
> 
> But I think below module is used GPL codes, because the text is described below in the module header.
> "Modelled after Linux' lib/ratelimit.c by Dave Young
>  <hidave.darkstar at gmail.com>, which is licensed GPLv2."
> (libinput/1.8.1-r0/libinput-1.8.1/src libinput-util.c ratelimit_test())
> 
> So, I'm thinking that the GPL is propagating, isn't it a problem?

I've looked at the referenced lib/ratelimit.c and I think we can justifiably
say that "modelled after" merely means "got the inspiration from". The API
differs and the implementation differs but I do not think that there is
sufficient similarity to claim one is a derivative of the other. The GPL
does not propagate here IMO.

Cheers,
   Peter, not a lawyer.