You can be sure they don't

It would explain the quality level of the ATI drivers, though. 

It's not unusual that the knowledge about how hardware works is codified in QA procedures,
designer knowledge, and a lot of notes that don't form a coherent document. The economics of
this particular market is that there really isn't time to write up documents that will explain
how to use the hardware to an outsider before the device needs to have drivers already written
and available to the public, and there's been little reason to write up such documents after
the driver is written.

Furthermore, there are a lot of corner cases, where the vendor driver doesn't try doing
something, and the hardware designers didn't except the driver writers to try it, and so
nobody's bothered to figure out if it would cause problems or not. They avoid trying to
evaluate a combinatorial explosion of unknown interactions by only checking the ones that
people are interested in, which is a big help in getting work done in a reasonable amount of
time, but only if the process is interactive. (And it's likely that a different implementation
of high-level 3D operations on the low-level units they have would hit different combinations
than the ones that the designers have verified to work together)