amdgpu ib_ring_test failed debian-sid-ppc64 4.12.4-ajp

[drm] amdgpu kernel modesetting enabled.
[drm] initializing kernel modesetting (VERDE 0x1002:0x683F 0x1682:0x3246 0x00).
amdgpu 0000:01:00.0: VM size (-1) must be a power of 2
[drm] register mmio base: 0x10000000
[drm] register mmio size: 262144
ATOM BIOS: 113-775AZNJ-20
[drm] GPU posting now...
[drm] Changing default dispclk from 600Mhz to 625Mhz
[drm] vm size is 64 GB, block size is 13-bit
amdgpu 0000:01:00.0: VRAM: 1024M 0x0000000000000000 - 0x000000003FFFFFFF (1024M                             used)
amdgpu 0000:01:00.0: GTT: 3072M 0x0000000040000000 - 0x00000000FFFFFFFF
[drm] Detected VRAM RAM=1024M, BAR=256M
[drm] RAM width 128bits UNKNOWN
[TTM] Zone  kernel: Available graphics memory: 4084698 kiB
[TTM] Zone   dma32: Available graphics memory: 2097152 kiB
[TTM] Initializing pool allocator
[TTM] Initializing DMA pool allocator
[drm] amdgpu: 1024M of VRAM memory ready
[drm] amdgpu: 3072M of GTT memory ready.
[drm] GART: num cpu pages 786432, num gpu pages 786432
amdgpu 0000:01:00.0: PCIE GART of 3072M enabled (table at 0x0000000000040000).
[drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[drm] Driver supports precise vblank timestamp query.
amdgpu 0000:01:00.0: amdgpu: using MSI.
[drm] amdgpu: irq initialized.
[drm] AMDGPU Display Connectors
[drm] Connector 0:
[drm]   DP-1
[drm]   HPD1
[drm]   DDC: 0x195c 0x195c 0x195d 0x195d 0x195e 0x195e 0x195f 0x195f
[drm]   Encoders:
[drm]     DFP1: INTERNAL_UNIPHY2
[drm] Connector 1:
[drm]   HDMI-A-1
[drm]   HPD4
[drm]   DDC: 0x1950 0x1950 0x1951 0x1951 0x1952 0x1952 0x1953 0x1953
[drm]   Encoders:
[drm]     DFP2: INTERNAL_UNIPHY2
[drm] Connector 2:
[drm]   DVI-I-1
[drm]   HPD2
[drm]   DDC: 0x194c 0x194c 0x194d 0x194d 0x194e 0x194e 0x194f 0x194f
[drm]   Encoders:
[drm]     DFP3: INTERNAL_UNIPHY
[drm] Connector 3:
[drm]   VGA-1
[drm]   DDC: 0x1958 0x1958 0x1959 0x1959 0x195a 0x195a 0x195b 0x195b
[drm]   Encoders:
[drm]     CRT1: INTERNAL_KLDSCP_DAC1
amdgpu 0000:01:00.0: fence driver on ring 0 use gpu addr 0x0000000040000010, cpu                             addr 0xc0000001f7dab010
amdgpu 0000:01:00.0: fence driver on ring 1 use gpu addr 0x0000000040000020, cpu                             addr 0xc0000001f7dab020
amdgpu 0000:01:00.0: fence driver on ring 2 use gpu addr 0x0000000040000030, cpu                             addr 0xc0000001f7dab030
amdgpu 0000:01:00.0: fence driver on ring 3 use gpu addr 0x0000000040000040, cpu                             addr 0xc0000001f7dab040
amdgpu 0000:01:00.0: fence driver on ring 4 use gpu addr 0x0000000040000050, cpu                             addr 0xc0000001f7dab050
[drm] probing gen 2 caps for device 1957:451 = 23d482/0
[drm] PCIE gen 2 link speeds already enabled
[drm] ring test on 0 succeeded in 8 usecs
[drm] ring test on 1 succeeded in 1 usecs
[drm] ring test on 2 succeeded in 2 usecs
[drm] ring test on 3 succeeded in 3 usecs
[drm] ring test on 4 succeeded in 4 usecs
[drm:.gfx_v6_0_ring_test_ib] *ERROR* amdgpu: ib test failed (scratch(0x2140)=0xC                            AFEDEAD)
[drm:.amdgpu_ib_ring_tests] *ERROR* amdgpu: failed testing IB on GFX ring (-22).
[drm:.amdgpu_device_init] *ERROR* ib ring test failed (-22).
[drm] fb mappable at 0xC00644000
[drm] vram apper at 0xC00000000
[drm] size 8294400
[drm] fb depth is 24
[drm]    pitch is 7680
Console: switching to colour frame buffer device 240x67
amdgpu 0000:01:00.0: fb0: amdgpudrmfb frame buffer device
[drm] Initialized amdgpu 3.15.0 20150101 for 0000:01:00.0 on minor 0
[drm] Initialized vgem 1.0.0 20120112 for virtual device on minor 1