Dnia środa, 30 stycznia 2019 13:42:33 CET piszesz:
> Does the attached patch fix the issue?
> 
> Christian.
> 
> .....

Thanks for the rapid response, but unfortunately no. 
System freezes and only mouse pointer is movable (cannot switch tty's, reboot 
by pwr button, tree-finger-salute doesn't work also).

Here is a trace log after applying the patch. I'm attaching it because it 
looks different:

<4>[   46.864336] ------------[ cut here ]------------
<2>[   46.864343] kernel BUG at drivers/gpu/drm/ttm/ttm_bo.c:196!
<4>[   46.864361] invalid opcode: 0000 [#1] PREEMPT SMP
<4>[   46.864369] CPU: 3 PID: 10966 Comm: plasmashel:cs0 Not tainted 5.0.0-
rc1+ #44
<4>[   46.864373] Hardware name: LENOVO 80E3/Lancer 5B2, BIOS A2CN45WW(V2.13) 
08/04/2016
<4>[   46.864388] RIP: 0010:ttm_bo_ref_bug+0x0/0x8 [ttm]
<4>[   46.864393] Code: 00 00 08 00 75 0c 48 83 c7 0c 4c 39 cf 75 ab 31 c0 c3 
b8 01 00 00 00 c3 66 90 f0 ff 8f a4 00 00 00 c3 0f 1f 84 00 00 00 00 00 <0f> 0b 
66 0f 1f 44 00 00 53 48 8b 07 48 89 fb 48 8b 40 18 48 8b 40
<4>[   46.864397] RSP: 0018:ffffa86fc1263af8 EFLAGS: 00010247
<4>[   46.864403] RAX: ffff8c7b133a787c RBX: ffffa86fc1263c48 RCX: ffff8c7b0f7698f8
<4>[   46.864406] RDX: ffff8c7b133a78f8 RSI: ffff8c7b11aa2800 RDI: ffff8c7b133a787c
<4>[   46.864410] RBP: ffff8c7ac16d1b38 R08: ffff8c7b1348d0f8 R09: ffffa86fc12639b0
<4>[   46.864414] R10: ffffcfd6c84d07c0 R11: 0000000000000003 R12: ffffffffc0364c10
<4>[   46.864417] R13: ffffa86fc1263be0 R14: 0000000000000000 R15: 
ffffa86fc1263c48
<4>[   46.864422] FS:  00007f3e34019700(0000) GS:ffff8c7b17b80000(0000) knlGS:
0000000000000000
<4>[   46.864426] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4>[   46.864430] CR2: 00007fb1cb765000 CR3: 000000021333e000 CR4: 
00000000000406e0
<4>[   46.864433] Call Trace:
<4>[   46.864446]  ttm_bo_del_from_lru+0xab/0xc8 [ttm]
<4>[   46.864456]  ttm_eu_reserve_buffers+0x140/0x2c8 [ttm]
<4>[   46.864557]  amdgpu_cs_ioctl+0x4ee/0x1b08 [amdgpu]
<4>[   46.864575]  ? __switch_to_asm+0x40/0x70
<4>[   46.864668]  ? amdgpu_cs_find_mapping+0x110/0x110 [amdgpu]
<4>[   46.864678]  drm_ioctl_kernel+0xa4/0xe8<4>[   46.864686]  
drm_ioctl+0x1db/0x358
<4>[   46.864767]  ? amdgpu_cs_find_mapping+0x110/0x110 [amdgpu]
<4>[   46.864848]  amdgpu_drm_ioctl+0x44/0x78 [amdgpu]
<4>[   46.864859]  do_vfs_ioctl+0x9f/0x618
<4>[   46.864867]  ksys_ioctl+0x5b/0x88
<4>[   46.864874]  __x64_sys_ioctl+0x11/0x18
<4>[   46.864881]  do_syscall_64+0x50/0x168
<4>[   46.864888]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
<4>[   46.864895] RIP: 0033:0x7f3e4a939fa7
<4>[   46.864900] Code: 00 00 00 75 0c 48 c7 c0 ff ff ff ff 48 83 c4 18 c3 e8 8d 
dc 01 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 b8 10 00 00 00 0f 05 <48> 3d 
01 f0 ff ff 73 01 c3 48 8b 0d a9 ae 0c 00 f7 d8 64 89 01 48
<4>[   46.864904] RSP: 002b:00007f3e34018ab8 EFLAGS: 00000246 ORIG_RAX: 
0000000000000010
<4>[   46.864909] RAX: ffffffffffffffda RBX: 00007f3e34018c58 RCX: 00007f3e4a939fa7
<4>[   46.864913] RDX: 00007f3e34018b40 RSI: 00000000c0186444 RDI: 
0000000000000010
<4>[   46.864916] RBP: 00007f3e34018b40 R08: 00007f3e34018c80 R09: 
00007f3e34018c58
<4>[   46.864920] R10: 00007f3e34018ca0 R11: 0000000000000246 R12: 
00000000c0186444
<4>[   46.864923] R13: 0000000000000010 R14: 000055555e550d70 R15: 
0000000000000003
<4>[   46.864929] Modules linked in: rfcomm nf_tables ebtable_nat ip_set 
nfnetlink ebtable_filter ebtables ip6table_filter ip6_tables overlay squashfs 
loop bnep ipv6 rtsx_usb_ms memstick rtsx_usb_sdmmc rtsx_usb ath3k btusb 
btintel bluetooth ecdh_generic uvcvideo videobuf2_vmalloc videobuf2_memops 
videobuf2_v4l2 videobuf2_common videodev media kvm_amd ath9k kvm ath9k_common 
irqbypass ath9k_hw crc32_pclmul mac80211 sdhci_pci cqhci sdhci 
ghash_clmulni_intel serio_raw mmc_core ath cfg80211 amdgpu mfd_core chash 
gpu_sched xhci_pci ttm ehci_pci xhci_hcd ehci_hcd sp5100_tco
<4>[   46.864981] ---[ end trace 7bdf1a5927cdc874 ]---

Thanks,
Przemek.