R: Need help to make a Radeon HD6970 to work on a G5

Hello,
this is my really old guide about install linux on PowerMac G5 (quad) but the append to linux kernel are working today too.
I have on My Quad A Quadro and a 6570 HD <-- for linux.

this is the link.
hope it will help you
[PPC] Instruction for Install Ubuntu & sons on PowerMac G5 Quad with Radeon HD (ubuntuforums.org)<https://ubuntuforums.org/showthread.php?t=2274612>

Ciao
Luigi

________________________________
Da: Link Electronics <[email protected]>
Inviato: giovedì 12 settembre 2024 00:58
A: [email protected] <[email protected]>
Oggetto: Re: Need help to make a Radeon HD6970 to work on a G5

I forgot to say that I have installed firmware-linux-nonfree and firmware-amd-graphics, and the last lines of dsmeg actually are:
[drm:uvd_v1_0_ib_test [radeon]] *ERROR* radeon: fence wait time out.
[drm:radeon_ib_ring_tests [radeon]] *ERROR* radeon: failed testing IB on ring 5 (-110).

On Wed, Sep 11, 2024 at 7:44 PM Link Electronics <[email protected]<mailto:[email protected]>> wrote:
Hello everyone, I would like to thank Adrian Glaubitz in advance for his many years of continuing to support the PowerPC platform on Debian Linux. I have a PowerMac G5 Late 2005, been using it for a few months now and was using the geforce 6600LE video card that came with it, I compiled some projects like DevilutionX, SpaceCadet Pinball, Nblood, Sonic decompilation games Mupen64plus etc and made them run with the geforce, but the performance is bad. Few days ago I changed it to a Radeon HD6970, it's a Cayman XT, I have the xserver-xorg-video-radeon and ati installed, but when loading LightDM or XFCE4, the image crashes with artifacts, I can switch to a tty console, in dmesg radeon says GPU lockup in ring 0 several times and in the end there is an error in drm:v1_0_ib_test and drm:radeon_ib_ring_tests, listing in lspci -k , it says kernel in use: radeon and kernel modules: radeon, amdgpu. I'm using linux-image-6.10.9-powerpc64 (4kb pagesize?) I can make the screen work with the framebuffer but no hw acceleration then.
What can I do to try to resolve this?

Thanks in advance
Best regards, Link.