Portable GFX Chipsets for Amiga?

[Iggy]

Even the open Unix projects has big problems with this because of the lack of documentation. PowerVR and Mali I guess are the chips one would be looking into.

So the documentation is in essence one early step to evaluate the feasibility.

When you start thinking about those GPUs, and the fact that they are often incorporated into ARM processors, then the next logical step is full emulation.
So why connect it to an Amiga?

Kronos is right.
It is simpler to move to an NG system.

[Iggy]

Rather than blast the idea I'd suggest looking into open source mobile drivers like http://limadriver.org/ and the Raspberry Pi's GPU http://www.broadcom.com/products/BCM2835

It might have an ARM onboard but it's not mindblowingly fast. There are also CPU-less GPUs from Broadcom that could be used. So it might be feasible but it would probably be a large project for a hobbyist.

I'm not trying to "blast" the idea, it just seems a little weird to use a device with a processor that runs at several hundred megahertz to aid another device that runs at a small fraction of that.