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Add the full text of the copyleft-next-0.3.1 license to the kernel tree as well as the required tags for reference and tooling. The license text was copied directly from the copyleft-next project's git tree [0]. Discussion of using copyleft-next-0.3.1 on Linux started since June, 2016 [1]. In the end Linus' preference was to have drivers use MODULE_LICENSE("GPL") to make it clear that the GPL applies when it comes to Linux [2]. Additionally, even though copyleft-next-0.3.1 has been found to be to be GPLv2 compatible by three attorneys at SUSE and Redhat [3], to err on the side of caution we simply recommend to always use the "OR" language for this license [4]. Even though it has been a goal of the project to be GPL-v2 compatible to be certain in 2016 I asked for a clarification about what makes copyleft-next GPLv2 compatible and also asked for a summary of benefits. This prompted some small minor changes to make compatibility even further clear and as of copyleft 0.3.1 compatibility should be crystal clear [5]. The summary of why copyleft-next 0.3.1 is compatible with GPLv2 is explained as follows: Like GPLv2, copyleft-next requires distribution of derivative works ("Derived Works" in copyleft-next 0.3.x) to be under the same license. Ordinarily this would make the two licenses incompatible. However, copyleft-next 0.3.1 says: "If the Derived Work includes material licensed under the GPL, You may instead license the Derived Work under the GPL." "GPL" is defined to include GPLv2. In practice this means copyleft-next code in Linux may be licensed under the GPL2, however there are additional obvious gains for bringing contributions from Linux outbound where copyleft-next is preferred. A summary of benefits why projects outside of Linux might prefer to use copyleft-next >= 0.3.1 over GPLv2: o It is much shorter and simpler o It has an explicit patent license grant, unlike GPLv2 o Its notice preservation conditions are clearer o More free software/open source licenses are compatible with it (via section 4) o The source code requirement triggered by binary distribution is much simpler in a procedural sense o Recipients potentially have a contract claim against distributors who are noncompliant with the source code requirement o There is a built-in inbound=outbound policy for upstream contributions (cf. Apache License 2.0 section 5) o There are disincentives to engage in the controversial practice of copyleft/ proprietary dual-licensing o In 15 years copyleft expires, which can be advantageous for legacy code o There are explicit disincentives to bringing patent infringement claims accusing the licensed work of infringement (see 10b) o There is a cure period for licensees who are not compliant with the license (there is no cure opportunity in GPLv2) o copyleft-next has a 'built-in or-later' provision The first driver submission to Linux under this dual strategy was lib/test_sysctl.c through commit |
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deprecated | ||
dual | ||
exceptions | ||
preferred |