hmm, and how about this ?
is this signature check problem
root@simpleminer:~# dmesg | grep amd
[ 0.089480] amd_nb: Cannot enumerate AMD northbridges
[ 0.718488] amdgpu: module verification failed: signature and/or required key missing - tainting kernel[ 0.721907] [drm] amdgpu kernel modesetting enabled.
[ 0.726883] fb: switching to amdgpudrmfb from VESA VGA
[ 0.727399] amdgpu 0000:01:00.0: Invalid ROM contents
[ 0.727476] amdgpu 0000:01:00.0: VRAM: 4096M 0x0000000000000000 - 0x00000000FFFFFFFF (4096M used)
[ 0.727478] amdgpu 0000:01:00.0: GTT: 4096M 0x0000000100000000 - 0x00000001FFFFFFFF
[ 0.727550] [drm] amdgpu: 4096M of VRAM memory ready
[ 0.727551] [drm] amdgpu: 4096M of GTT memory ready.
[ 0.728746] amdgpu 0000:01:00.0: amdgpu: using MSI.
[ 0.728784] [drm] amdgpu: irq initialized.
[ 0.728920] amdgpu: powerplay initialized
[ 0.729157] amdgpu 0000:01:00.0: fence driver on ring 0 use gpu addr 0x0000000100000008, cpu addr 0xffff880210a50008
[ 0.729188] amdgpu 0000:01:00.0: fence driver on ring 1 use gpu addr 0x000000010000001c, cpu addr 0xffff880210a5001c
[ 0.729211] amdgpu 0000:01:00.0: fence driver on ring 2 use gpu addr 0x0000000100000030, cpu addr 0xffff880210a50030
[ 0.729232] amdgpu 0000:01:00.0: fence driver on ring 3 use gpu addr 0x0000000100000044, cpu addr 0xffff880210a50044
[ 0.729252] amdgpu 0000:01:00.0: fence driver on ring 4 use gpu addr 0x0000000100000058, cpu addr 0xffff880210a50058
[ 0.729271] amdgpu 0000:01:00.0: fence driver on ring 5 use gpu addr 0x000000010000006c, cpu addr 0xffff880210a5006c
[ 0.729293] amdgpu 0000:01:00.0: fence driver on ring 6 use gpu addr 0x0000000100000080, cpu addr 0xffff880210a50080
[ 0.729313] amdgpu 0000:01:00.0: fence driver on ring 7 use gpu addr 0x0000000100000094, cpu addr 0xffff880210a50094
[ 0.729329] amdgpu 0000:01:00.0: fence driver on ring 8 use gpu addr 0x00000001000000a8, cpu addr 0xffff880210a500a8
[ 0.729378] amdgpu 0000:01:00.0: fence driver on ring 9 use gpu addr 0x00000001000000bc, cpu addr 0xffff880210a500bc
[ 0.729397] amdgpu 0000:01:00.0: fence driver on ring 10 use gpu addr 0x00000001000000d0, cpu addr 0xffff880210a500d0
[ 0.729768] amdgpu 0000:01:00.0: fence driver on ring 11 use gpu addr 0x000000000089c420, cpu addr 0xffffc90001a5a420
[ 0.729876] amdgpu 0000:01:00.0: fence driver on ring 12 use gpu addr 0x00000001000000f8, cpu addr 0xffff880210a500f8
[ 0.729897] amdgpu 0000:01:00.0: fence driver on ring 13 use gpu addr 0x000000010000010c, cpu addr 0xffff880210a5010c
[ 0.976249] fbcon: amdgpudrmfb (fb0) is primary device
[ 0.976324] amdgpu 0000:01:00.0: fb0: amdgpudrmfb frame buffer device
[ 0.984715] [drm] Initialized amdgpu 3.2.0 20150101 for 0000:01:00.0 on minor 0