"Downstream" means everybody, of course, forever. You've just lost your patented tech, so if you don't want to sell it outright, you can't touch anything GPL. G

"Downstream" means everybody, of course, forever. You've just lost your patented tech, so if you don't want to sell it outright, you can't touch anything GPL. Given how complex technologies are, now, that severely limits where GPL2 and 3 can be used. So you might ask, why does Google use the Linux kernel? Perhaps because they don't have to modify the kernel to accommodate inventions they wish to preserve, for public software such as Android; but more importantly the kernel is useless by itself and the license doesn't extend to libraries (Google spent billions recreating the GNU libraries to be sure of that), so the license for the kernel has no practical importance. The rights granted are "stranded", as it were. Clever on the part of Google. But in most cases, the GPL or MPL can't be gotten around in that manner. The googleable rubric for GPL2 is "GPL's Implied Patent Grant." In sum, the GPL seizes all relevant patent rights from any contributor (regardless of whether those contributions related to their patents, IIRC) and any distributor. In some cases that doesn't matter - in other cases, it does. If you want to retain control of who gets to use your patents, and patented tech, that's a big problem. If your invention is a hardware invention, the GPL still scoops it up - their language doesn't exclude rights to hardware inventions - so you may actually have the right to build any such patented hardware as long as you put Linux in it: if the patent owner touched Linux. It would take a court case to be certain this wasn't a risk. This also seems to mean (even for GPL2) that if you explicitly license one entity to use GPLed software with your patented tech (hardware or software), then you've just given a free license to every soul on earth to do the same, with no royalties. In some cases, that might not matter. In many other cases, it does. "In contrast, a GPLv2 licensee, under the doctrine of implied patent license, is free to practice any patent claims held by the licensor that cover “reasonably contemplated uses” of the GPL’d code, which may very well include creation and distribution of modified works since the GPL’s terms, under which the patented code is distributed, expressly permits such activity. Further supporting this result is the Federal Circuit’s pronouncement that the recipient of a patented article has, not only an implied license to make, use, and sell the article, but also an implied patent license to repair the article to enable it to function properly, Bottom Line Mgmt., Inc. v. Pan Man, Inc., 228 F.3d 1352 (Fed. Cir. 2000). Additionally, the Federal Circuit extended that rule to include any future recipients of the patented article, not just the direct recipient from the distributor. This theory comports well with the idea of Free Software, whereby software is distributed among many entities within the community for the purpose of constant evolution and improvement. In this way, the law of implied patent license used by the GPLv2 ensures that the community mutually benefits from the licensing of patents to any single community member." https://copyleft.org/guide/comprehensive-gpl-guidech7.html https://copyleft.org/guide/comprehensive-gpl-guidech7.html