[drm:.r600_ring_test [radeon]] *ERROR* radeon: ring 0 test failed (scratch(0x8504)=0xCAFEDEAD)

Submitted by Rui Salvaterra @rsalvaterra

Assigned to Default DRI bug account

Link to original bug (#95015)

Description

Created attachment 123045
dmesg

Full dmesg attached. I have a Power Mac G5 (late 2005, PCIe) with a Radeon HD 6450 (CAICOS, x86 BIOS) installed on the PCIe x16 slot, and I get this error on boot. I also have a GeForce 6600 (Open Firmware) on a PCIe x8 slot, which works fine, minus the usual nouveau caveats. I have no idea if this is related at all, but the x16 slot is directly connected to the U4 northbridge, and is capable of bypassing the DART IOMMU for 64-bit DMA capable devices (like the Radeon). The other slots are connected to a PCIe bridge on the HyperTransport bus, and DMA always goes through the DART. If needed, I can provide ssh access to the machine.

Attachment 123045, "dmesg":
dmesg.txt