If I were Allwinner, I'd be quite nervous about open-sourcing my code. Who knows what patents it infringes?

I think you've put forward an important point many don't consider when debating why companies won't open source.

We have a winner!

This is why the recent proposal by Bunnie of trading transparency against liability would be so important.

The API would expose what IP cores are inside the GPU.

A competitor could easily dissect the code and figure out what blocks and/or techniques are violating their patent rights.

> "The API would expose what IP cores are inside the GPU."

How would an open-source driver developed by a third party be less effective at doing so?

The third-party is probing into a black box. They have no idea what is or isn't there. So it could be plausible deniability on the side of the chipmaker.

How about documentation then? Let's say Allwinner releases C header files, plus high level descriptions of what each function does. Do they still maintain plausible deniability if the hardware design infringes on patents?

It means they don't need to get lawyers involved to check for any licencing gotchas from other non-free code in the tool chain. They might see it as a liability or reveals other tangentially related proprietary details of their tooling. There may not be much formal documentation, and if there is it would likely need to be combed through, updated, translated, etc.

Even without getting lawyers involved, I don't see how they could do any of the above tasks for less than the price of this Kickstarter.

> "It means they don't need to get lawyers involved to check for any licencing gotchas from other non-free code in the tool chain."

They don't need to open source the whole toolchain, just the parts of the code they own/wrote themselves. For the parts of the toolchain they can provide documentation (writing it out if this documentation needed to be created/revised) to fill in the missing pieces.

> "I don't see how they could do any of the above tasks for less than the price of this Kickstarter."

You seem to be overlooking that reverse engineering hardware drivers is a hugely inefficient process. People only do it out of necessity. Furthermore, the Kickstarter has set modest goals of enhancing the work that has already been done (MPEG2 acceleration, etc...), the end result is not a driver that can be used for more general purpose graphics acceleration (e.g. no OpenGL driver). That's not to say it isn't a good step forward, I welcome it, but you should be aware that there's a long road ahead after the work for the Kickstarter has been completed. If you don't believe me, look at the ongoing work being done by the Nouveau team.