Hi Logan,
The kernel version is quite old (3.16.7). Perhaps you can try something
newer. Nouveau continually has improvements practically with each newer
kernel version.
Perhaps something to consider, try the easy way out and use a
pre-compiled kernel deb package that i have available. I have kernels as
new as 4.4.0 available suitable for Powermac G5's.
At least these could perhaps be a better baseline as these kernels are
known to be working for many Powermac G5's (AGP & PCIe GPU's along with
a few generations of nVidia GPU's (some even older than yours). Makes it
easier to have a side by side comparison.
Your call, link is below if interested.
https://drive.google.com/folderview?id=0B8pqd5Ots1vfT2puX09CYjEwcFk&usp=drive_web
Many have used them successfully in the past and have got their G5
Powermacs running with nouveau.
I'm not so sure that MSI interrupts are ever enabled on AGP GPU's in the
first place (PCIe based GPU's are a different story).
It would be interesting to see your cat /proc/interrupts log as well.
Regarding your EDID issue, can you try the other DVI connector of your
video card or cable or alternatively try another display out if the
issue still persists.
Most Apple OEM ATI Radeon GPU's have their own issues as well. But
that's another story.
Regards,
Peter
