AMD/ATI HD series PCI

I'm using an HP ZX6000 workstation right now. Anyone had any luck getting an AMD/ATI HD series (2xxx, 3xxx, 4xxx) card working with DRI2? If so, what machine? After updating Linux 2.6.x to Linux 3.2.x, my radeon 7000 series (on board) shows itself as having direct rendering, and this leaves me hopeful that DRM/DRI2 on ia64 isn't just inherently broken.

I realize the issues with running a graphics card with x86 firmware vs native EFI firmware. On Debian/sparc, I was able to use a GeForce 4000 MX since the int10 module of Xorg seems to emulate just enough real-mode x86 to allow the card to boot up. I can run OpenArena on it with hardware acceleration -- so I know it is possible to do, both in theory and practice. I got Xorg running on a 8400GS once, but it wasn't very stable. I've heard about getting PowerPC machines to use Radeon cards too -- so I was curious if anyone had any experiences (postive or negative) while using AMD/ATI HD series cards. I noticed that using an Nvidia 8400 GS caused the system to not POST -- it seems there might be some firmware issue, or perhaps just a simple power issue. I'm not sure. I'd like to get hardware accelerated GL 2.x with upgradability to 3.x when Mesa 8+ becomes available, basically.