Hi. I assume that the error occurs on the PPC64 system because of disabled HA (Hardware Acceleration) too:
According to https://bugs.freedesktop.org/show_bug.cgi?id=99851 a "ring 0 test failed" message from drm means that HA gets disabled. dmesg | grep -i drm [ 5.621228] [drm] radeon kernel modesetting enabled. [ 5.662906] [drm] initializing kernel modesetting (CEDAR 0x1002:0x68FA 0x174B:0xE127 0x00). [ 5.974683] [drm] GPU not posted. posting now... [ 6.017017] [drm] Detected VRAM RAM=1024M, BAR=256M [ 6.017018] [drm] RAM width 64bits DDR [ 6.082254] [drm] radeon: 1024M of VRAM memory ready [ 6.195713] [drm] radeon: 1024M of GTT memory ready. [ 6.220009] [drm] Loading CEDAR Microcode [ 6.335990] [drm] Internal thermal controller with fan control [ 6.364947] [drm] radeon: dpm initialized [ 6.396903] [drm] GART: num cpu pages 16384, num gpu pages 262144 [ 6.458639] [drm] PCIE GART of 1024M enabled (table at 0x0000000000150000). [ 6.531588] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). [ 6.576700] [drm] Driver supports precise vblank timestamp query. [ 6.641177] [drm] radeon: irq initialized. [ 6.834702] [drm:.r600_ring_test [radeon]] *ERROR* radeon: ring 0 test failed (scratch(0x8504)=0xCAFEDEAD) [ 6.863707] [drm] Radeon Display Connectors [ 6.880862] [drm] Connector 0: [ 6.880863] [drm] DVI-I-1 [ 6.880865] [drm] HPD2 [ 6.880867] [drm] DDC: 0x6430 0x6430 0x6434 0x6434 0x6438 0x6438 0x643c 0x643c [ 6.880868] [drm] Encoders: [ 6.880869] [drm] DFP1: INTERNAL_UNIPHY1 [ 6.880870] [drm] CRT2: INTERNAL_KLDSCP_DAC2 [ 6.880875] [drm] Connector 1: [ 6.902720] [drm] DVI-I-2 [ 6.913316] [drm] HPD4 [ 6.987101] [drm] DDC: 0x6440 0x6440 0x6444 0x6444 0x6448 0x6448 0x644c 0x644c [ 7.001856] [drm] Encoders: [ 7.007757] [drm] DFP2: INTERNAL_UNIPHY [ 7.016093] [drm] CRT1: INTERNAL_KLDSCP_DAC1 [ 7.112647] [drm] fb mappable at 0x90360000 [ 7.120638] [drm] vram apper at 0x90000000 [ 7.128797] [drm] size 7733248 [ 7.134875] [drm] fb depth is 24 [ 7.141298] [drm] pitch is 6400 [ 7.212427] radeon 0000:0a:00.0: fb0: radeondrmfb frame buffer device [ 7.238821] [drm] Initialized radeon 2.50.0 20080528 for 0000:0a:00.0 on minor 0 I tested these kernel versions: 4.18.0-3-powerpc64 (official kernel from Debian PPC64 sid) 4.19.28-rt16 (self compiled, with realtime patches) Both result in "ring 0 test failed". In my opinion it would be great if: 1) xserver-xorg-video-radeon_1%3a19.1.0-1 would not fail but fall back to frame buffer device like xserver-xorg-video-radeon_1%3a19.0.1-1 2) the "ring 0 test" would not fail According to the last post from the link above the failure was seen in 4.14.4 and 4.15-rc2 but not in kernel 4.17.2. Maybe I should get/compile a linux 4.17.2 kernel. Thank you and best regards, Ralf
