https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_248/fi-byt-j1900/igt@kms_busy@extended-modeset-hang-oldfb-with-reset-render-a.html

4> [79.837014] Unclaimed read from register 0x1f0034
<4> [79.837150] WARNING: CPU: 2 PID: 208 at drivers/gpu/drm/i915/intel_uncore.c:1033 __unclaimed_reg_debug+0x40/0x50 [i915]
<4> [79.837156] Modules linked in: snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic i915 coretemp btusb snd_hda_intel btrtl btbcm crct10dif_pclmul btintel crc32_pclmul snd_hda_codec bluetooth ghash_clmulni_intel snd_hwdep snd_hda_core snd_pcm ecdh_generic r8169 realtek lpc_ich prime_numbers i2c_hid
<4> [79.837196] CPU: 2 PID: 208 Comm: kworker/2:2 Tainted: G     U            5.1.0-rc2-ga1e7e8ca746c-drmtip_248+ #1
<4> [79.837202] Hardware name: GIGABYTE GB-BXBT-1900/MZBAYAB-00, BIOS F6 02/17/2015
<4> [79.837288] Workqueue: events_long i915_hangcheck_elapsed [i915]
<4> [79.837376] RIP: 0010:__unclaimed_reg_debug+0x40/0x50 [i915]
<4> [79.837383] Code: 74 05 5b 5d 41 5c c3 45 84 e4 48 c7 c0 44 d4 4e c0 48 c7 c6 3a d4 4e c0 48 0f 44 f0 89 ea 48 c7 c7 4d d4 4e c0 e8 a0 82 ce c0 <0f> 0b 83 2d 57 46 1b 00 01 5b 5d 41 5c c3 66 90 41 56 41 55 41 89
<4> [79.837388] RSP: 0018:ffffacb1001e37c8 EFLAGS: 00010086
<4> [79.837395] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
<4> [79.837401] RDX: 0000000000000007 RSI: 0000000000000000 RDI: 00000000ffffffff
<4> [79.837406] RBP: 00000000001f0034 R08: 0000000000000000 R09: 0000000000000001
<4> [79.837412] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
<4> [79.837417] R13: 0000000000000000 R14: 00000000ffffffff R15: 0000000000000206
<4> [79.837423] FS:  0000000000000000(0000) GS:ffff9c7cfbb00000(0000) knlGS:0000000000000000
<4> [79.837429] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4> [79.837434] CR2: 00007f09bca831e0 CR3: 0000000012214000 CR4: 00000000001006e0
<4> [79.837440] Call Trace:
<4> [79.837533]  fwtable_read32+0x1e2/0x240 [i915]
<4> [79.837620]  vlv_program_watermarks+0x464/0x7a0 [i915]
<4> [79.837719]  vlv_optimize_watermarks+0xc0/0xd0 [i915]
<4> [79.837812]  intel_atomic_commit_tail+0x2bf/0x12a0 [i915]
<4> [79.837825]  ? flush_workqueue+0x236/0x530
<4> [79.837835]  ? lockdep_hardirqs_on+0xe3/0x1b0
<4> [79.837947]  intel_atomic_commit+0x244/0x330 [i915]
<4> [79.837964]  drm_atomic_helper_commit_duplicated_state+0xc4/0xd0
<4> [79.838053]  __intel_display_resume+0x7d/0xc0 [i915]
<4> [79.838145]  intel_finish_reset+0x49/0x130 [i915]
<4> [79.838227]  i915_reset_device+0x106/0x170 [i915]
<4> [79.838314]  ? i915_gem_set_wedged+0x60/0x60 [i915]
<4> [79.838330]  ? queue_work_node+0x70/0x70
<4> [79.838424]  i915_handle_error+0x22e/0x360 [i915]
<4> [79.838550]  i915_hangcheck_elapsed+0x3ba/0x4d0 [i915]
<4> [79.838568]  ? __drm_printfn_info+0x20/0x20
<4> [79.838597]  ? __lock_acquire+0x4a0/0x1590
<4> [79.838623]  ? process_one_work+0x1bf/0x610
<4> [79.838642]  process_one_work+0x245/0x610
<4> [79.838663]  worker_thread+0x37/0x380
<4> [79.838677]  ? process_one_work+0x610/0x610
<4> [79.838684]  kthread+0x119/0x130
<4> [79.838692]  ? kthread_park+0x80/0x80
<4> [79.838706]  ret_from_fork+0x3a/0x50
<4> [79.838735] irq event stamp: 67316
<4> [79.838742] hardirqs last  enabled at (67315): [<ffffffff819aeb6c>] _raw_spin_unlock_irqrestore+0x4c/0x60
<4> [79.838749] hardirqs last disabled at (67316): [<ffffffff819ae9dd>] _raw_spin_lock_irqsave+0xd/0x50
<4> [79.838756] softirqs last  enabled at (67248): [<ffffffff81c0033a>] __do_softirq+0x33a/0x4b9
<4> [79.838763] softirqs last disabled at (67241): [<ffffffff810b8f69>] irq_exit+0xa9/0xc0
<4> [79.838854] WARNING: CPU: 2 PID: 208 at drivers/gpu/drm/i915/intel_uncore.c:1033 __unclaimed_reg_debug+0x40/0x50 [i915]