How do those projects write open-source drivers for proprietary hardware legally? I know that there’s “clean-room” reverse engineering, but is it really a requirement? From what I understand, you can write docs about how the hardware works and then the other team can write a software based on that documentation.
What if the new software is just implementing the necessities for compatibility and other than that is a different product? Is it still illegal for just one team to do that?
You can actually literally watch marcan/lina/(more rarely)alyssa from asahi work on livestreams :) No, they don’t actually do that kind of clean-room. There’s no issue with learning about how the hardware works and directly applying that to writing drivers! Hardware and drivers aren’t even comparable, they’re complementary. One basically cannot infringe on the other. They mostly avoid touching Apple drivers, but even when they’ve had to poke at them it kinda just wasn’t a big deal IIRC.
Clean-room techniques come from actually cloning very similar things. Basically the original Phoenix BIOS cloning IBM. As a more recent example Wine/ReactOS.