The old classic argument around why Linux doesn't have a rigid internal API comes to mind (http://www.kroah.com/log/linux/stable_api_nonsense.html). Maybe there are commonalities between supporting Mir and Wayland that would allow Intel to create a more universal piece of software? If Canonical does the work to make the driver universal, wouldn't the whole community benefit?
I'm not a big fan of letting politics get in the way of engineering, and this smells of the fact that Intel is trying to battle ARM in a proxy war, with FOSS as collateral damage.
XMir support in intel's driver uses a significant amount of separate code. I'm not saying intel's actions are ok, but XMir is not creating anything more universal.
I'm not a big fan of letting politics get in the way of engineering, and this smells of the fact that Intel is trying to battle ARM in a proxy war, with FOSS as collateral damage.