Evening
@MicroTecture,
Very pleased to report that although I haven't had any luck with ppc Ubuntu live DVDs, the AGP Radeon HD4670 works perfectly under both Debian (sid 11) and OpenSUSE (Tumbleweed), both ppc64. The machine used for testing was a PM 7,3 (2x2GHz G5, PCI-X + AGP, 4 RAM slots)
I used a flashed GF 5200 PCI for the first few boot stages (to boot, the G5 does initially require a mac VGA card connected to a monitor), then switched the display to the Radeon HD.
I used Debian and OpenSuse installs from my Quad G5. The AGP Radeon HD4670 is fully accelerated under both and very snappy. glxinfo confirms direct rendering is working alright, as does glxgears which runs very smoothly. To be honest I couldn't see much difference as compared to e.g. the HD 5770 with the Quad.
Note that as with the Quad, you've got to install linux-firmware-nonfree under Debian to get PC Radeon HD cards to work. Your append should also include
Code:
radeon.modeset=1 nouveau.modeset=0
Re OpenSuse, I had to boot it using a boot CD (Adelie Linux in my case), since it appears that booting from GPT is only supported in later G5s (e.g. Quad G5 and possibly DC, essentially a stripped-down version of the Quad, and possibly the very last iMac G5 iSight). Which means, that if you do install it, you'll either have to use a boot cd to boot into it or to clone the GPT partitions to an Apple-partitioned hard drive following install.
To boot it from a boot CD, you would have to type c when reaching grub, then
Code:
root=(ieee1275/ultra<X>,gpt<Y>)
linux=/boot/vmlinuz root=/dev/sdb<Z> radeon.modeset=1 nouveau.modeset=0
initrd=/boot/initrd
boot
where <X> is either 0 or 1 depending on whether you're using the top HD bay (0) or the bottom one (1), <Y> is your boot partition, and <Z> is your root partition
As for Ubuntu, I couldn't get it to work for the life of me, as none of the flavours I tried resulted in me reaching the desktop, although the card appears to be correctly initialised, as in both the boot messages and splash screen get rendered. However upon where I should have been reaching the desktop, I am invariably greeted with a black screen. I tried with Mate 14.04, Lubuntu 14.04 as well as Mate 16.04 live DVDs. I however believe it might just be a matter of tweaking the append line once installed with a mac/flashed PC PCI VGA card. Adding
Code:
video=offb:off video=radeonfb:off video=nouveaufb:off radeon.agpmode=1 pci=realloc radeon.dpm=0
to
Code:
radeon.modeset=1 nouveau.modeset=0
was to no avail. However, there are probably further options to explore. But frankly even 16.04 is now a bit outdated and pales in comparison to the latest versions of Debian and OpenSuse.
So the take-home message is that you're probably safe to go ahead and get a hold of an AGP Radeon HD 4670 (or 4650, same chip with lower frequencies), at least as far as Debian and OpenSuse are concerned.
Enjoy and do let us know how you get on!
Cheers,
