Sorry for chiming in here, i’ve passively followed the discussion.

If you produce patches for a 3.14 kernel that solve this issue:

http://lists.freedesktop.org/archives/dri-devel/2013-November/049185.html

(thereby enabling AGP mode on mac mini G4’s, should still be quite a few of them around)

you can register me as a happy tester. My "uptime" with a powerpc AGP system is about two minutes :-) (although the system behaviour has changed somewhat with more recent kernels from a complete lockup to an endless loop).

Cheers

Jochen