https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_150/fi-cfl-8109u/igt@kms_vblank@pipe-c-wait-forked-busy.html

------------[ cut here ]------------
<4> [108.545061] vblank wait timed out on crtc 1
<4> [108.546028] WARNING: CPU: 3 PID: 1166 at drivers/gpu/drm/drm_vblank.c:1084 drm_wait_one_vblank+0x19b/0x1b0
<4> [108.546028] Modules linked in: snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic i915 x86_pkg_temp_thermal coretemp snd_hda_intel crct10dif_pclmul snd_hda_codec crc32_pclmul snd_hwdep snd_hda_core ghash_clmulni_intel btusb btrtl btbcm btintel bluetooth snd_pcm e1000e mei_me mei i2c_i801 ecdh_generic prime_numbers
<4> [108.546028] CPU: 3 PID: 1166 Comm: kms_vblank Tainted: G     U            4.20.0-rc4-ge556a1602bef-drmtip_150+ #1
<4> [108.546028] Hardware name: Intel Corporation NUC8i3BEH/NUC8BEB, BIOS BECFL357.86A.0037.2018.0614.2204 06/14/2018
<4> [108.546028] RIP: 0010:drm_wait_one_vblank+0x19b/0x1b0
<4> [108.546028] Code: fe ff ff e8 47 fc a5 ff 48 89 e6 4c 89 ff e8 1c 0d ab ff 45 85 ed 0f 85 15 ff ff ff 89 ee 48 c7 c7 b0 3e 0d 90 e8 45 f9 a5 ff <0f> 0b e9 00 ff ff ff 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 8b
<4> [108.546028] RSP: 0018:ffffa73940a1ba20 EFLAGS: 00010282
<4> [108.546028] RAX: 0000000000000000 RBX: ffffa15f998c0000 RCX: 0000000000000000
<4> [108.546028] RDX: 0000000000000000 RSI: ffffffff900ff0c2 RDI: 00000000ffffffff
<4> [108.546028] RBP: 0000000000000001 R08: 00000000f2a06360 R09: 0000000000000000
<4> [108.546028] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000218
<4> [108.546028] R13: 0000000000000000 R14: 00000000000010e6 R15: ffffa15fa476a768
<4> [108.546028] FS:  00007fcb7513c980(0000) GS:ffffa15fb5b80000(0000) knlGS:0000000000000000
<4> [108.546028] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
<4> [108.546028] CR2: 00007f918b994788 CR3: 00000002a61a6004 CR4: 00000000003606e0
<4> [108.546028] Call Trace:
<4> [108.546028]  ? wait_woken+0xa0/0xa0
<4> [108.546028]  skl_update_crtcs+0x1df/0x2b0 [i915]
<4> [108.546028]  intel_atomic_commit_tail+0x1e3/0xd20 [i915]
<4> [108.546028]  intel_atomic_commit+0x244/0x330 [i915]
<4> [108.546028]  drm_atomic_helper_set_config+0x7b/0x90
<4> [108.546028]  drm_mode_setcrtc+0x195/0x6b0
<4> [108.546028]  ? drm_mode_getcrtc+0x180/0x180
<4> [108.546028]  drm_ioctl_kernel+0x81/0xf0
<4> [108.546028]  drm_ioctl+0x2de/0x390
<4> [108.546028]  ? drm_mode_getcrtc+0x180/0x180
<4> [108.546028]  ? lockdep_hardirqs_on+0xe0/0x1b0
<4> [108.546028]  do_vfs_ioctl+0xa0/0x6e0
<4> [108.546028]  ? lock_acquire+0xa6/0x1c0
<4> [108.546028]  ? __task_pid_nr_ns+0xb9/0x1f0
<4> [108.546028]  ksys_ioctl+0x35/0x60
<4> [108.546028]  __x64_sys_ioctl+0x11/0x20
<4> [108.546028]  do_syscall_64+0x55/0x190
<4> [108.546028]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
<4> [108.546028] RIP: 0033:0x7fcb743c65d7
<4> [108.546028] Code: b3 66 90 48 8b 05 b1 48 2d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 81 48 2d 00 f7 d8 64 89 01 48
<4> [108.546028] RSP: 002b:00007ffc6fdbcda8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
<4> [108.546028] RAX: ffffffffffffffda RBX: 00007ffc6fdbcde0 RCX: 00007fcb743c65d7
<4> [108.546028] RDX: 00007ffc6fdbcde0 RSI: 00000000c06864a2 RDI: 0000000000000005
<4> [108.546028] RBP: 00007ffc6fdbcde0 R08: 0000000000000000 R09: 0000000000000000
<4> [108.546028] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000c06864a2
<4> [108.546028] R13: 0000000000000005 R14: 0000000000000000 R15: 0000000000000000
<4> [108.546028] irq event stamp: 62734
<4> [108.546028] hardirqs last  enabled at (62733): [<ffffffff8f0fef59>] console_unlock+0x3f9/0x5f0
<4> [108.546028] hardirqs last disabled at (62734): [<ffffffff8f0019b0>] trace_hardirqs_off_thunk+0x1a/0x1c
<4> [108.546028] softirqs last  enabled at (61870): [<ffffffff8fc0033a>] __do_softirq+0x33a/0x4b9
<4> [108.546028] softirqs last disabled at (61843): [<ffffffff8f0929f9>] irq_exit+0xa9/0xc0
<4> [108.546028] WARNING: CPU: 3 PID: 1166 at drivers/gpu/drm/drm_vblank.c:1084 drm_wait_one_vblank+0x19b/0x1b0
<4> [108.546028] ---[ end trace 0307bb3e77efbaaa ]---