The question is important because they are tearing the every spirit of opensource development.
They are making yet another graphics stack, like building own house on top of others. While the action is good, the effect on neighborhood is pretty disastrous.
They are destroying gallium with each progress of own driver. If they don't need gallium, why won't they come up with points why gallium is bad, what should be changed about it (both organisationary or technically).
Opensource is about cooperation - open code is only a requirement for it. When cooperation takes place(I didn't write complete acknowledgement, but cooperation), each company technology is boosted by synergy.
Right now Intel' policy of ignorance poisons cooperation for sake of faster development - it would unavoidably cripple progress of others at some time in future.
What is the reason for them to pick ignorance route ?, they sell chips, designs and licenses - not their open driver.
As example: if Intel is not following the policy, or if *other people* do not follow the policy - they should be handled as special case and their variations should be placed in side-branches.
If the deviation becomes so different (in functionality) as to be seen as collection of patches - RFC should be rised as of overtaking this modification as default against the current, rethinking the approach of the project (as in integrating the two version together) or, in rare case, starting a spin off(fork) - in case the difference due to the goals of each one results in complete different code.
The disadvantages of synergistic cooperative development will be covered by absence of bugs, regressions, integration problems (Intel APU with AMD card, or VMWare machine - as example).
Copypasting code doesn't solve integration, inter-cooperation, redundancy and debugging issues.
The idea of Gallium is that of cooperative development, no?