So do I understand it correctly, that this patch is for hardware that has been working, in some cases for 5 years; that it has been written after reading a public doc; and that it was not developed in response to a known bug or issue?
Code that does not conform to a public doc is NOT a bug.
A word to the wise: in all too many cases, the public docs and the private docs disagree. In some cases, the private docs directly contradict the public docs. And, in still other cases, the hardware contradicts the private docs. That's what makes this so much fun.
It's the implementation of the hardware, not the documentation, that matters.
Changes made in response to a reading of public docs, that are not known to resolve an actual observed problem, are a very risky thing to do, especially with old chipsets. They should be rejected outright unless they are confirmed to fix a problem.
We've had people push this kind of change in the past and break boards.
So tread carefully.
ron