>(If the driver is leaked, I would imagine it to be illegal to distribute it.
How so? This would be a 1st Amendment issue: you can't ban free speech. They tried this with deCSS, which could be printed out on a T-shirt. Of course, if it were leaked, it could be called a copyright issue, but copyright claims require the copyright holder to actively pursue those claims: if AMD didn't bother to pursue any claims, then what could anyone do about it?
You can't assert a copyright on a secret[1]. That's called a "trade secret", and those have no IP protection other than being able to sue the leaker if the secret gets out. You can't copyright facts, so implementing these "secrets" in computer code doesn't confer any kind of protection: the resulting code simply has regular copyright protection.
[1] Well, you can, but that just means other people can't copy it in its original form. AMD had authorized copies so they could write the code. The resulting code is not a copy of the secret document, it just uses facts from that document, and you can't copyright facts.
Similarly, if someone inside Coca-Cola shows you their master copy of the secret recipe for Coca-Cola, and you then write down a list of the ingredients and quantities and publish that on your blog, Coca-Cola can do nothing to you.
How so? This would be a 1st Amendment issue: you can't ban free speech. They tried this with deCSS, which could be printed out on a T-shirt. Of course, if it were leaked, it could be called a copyright issue, but copyright claims require the copyright holder to actively pursue those claims: if AMD didn't bother to pursue any claims, then what could anyone do about it?