MartinK has summarized it pretty well, I could not have said it better myself.

I have one more thing to add, though: android video drivers are a mess, because the android kernel is purposefully engineered in such a way that video drivers that work on android will not work on the upstream kernel. So even if a manufacturer has any incentive to make the android driver available, it won't work from a non-android system. This is why they made hacks like libhybris to combat this situation.

This article from Greg Kroah-Hartman summarizes it very well:
http://www.kroah.com/log/linux/andro...-problems.html