https://intel-gfx-ci.01.org/tree/drm-tip/drmtip_66/fi-hsw-4770/igt@gem_exec_suspend@basic-s3.html

[   60.735111] Display power well on
[   60.735161] WARNING: CPU: 2 PID: 147 at drivers/gpu/drm/i915/intel_display.c:8965 hsw_enable_pc8+0x637/0x680 [i915]
[   60.735162] Modules linked in: vgem snd_hda_codec_hdmi i915 x86_pkg_temp_thermal intel_powerclamp coretemp crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hda_codec_realtek snd_hda_codec_generic snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core mei_me snd_pcm e1000e mei lpc_ich prime_numbers
[   60.735179] CPU: 2 PID: 147 Comm: kworker/u16:2 Tainted: G    BUD           4.18.0-rc1-ge47233f783ee-drmtip_66+ #1
[   60.735180] Hardware name: LENOVO 10AGS00601/SHARKBAY, BIOS FBKT34AUS 04/24/2013
[   60.735184] Workqueue: events_unbound async_run_entry_fn
[   60.735219] RIP: 0010:hsw_enable_pc8+0x637/0x680 [i915]
[   60.735220] Code: ff e8 fd 66 a5 cf 0f 0b e9 9c fb ff ff e8 f1 66 a5 cf 0f 0b e9 df fb ff ff e8 e5 66 a5 cf 0f 0b e9 b4 fa ff ff e8 d9 66 a5 cf <0f> 0b e9 87 fa ff ff e8 cd 66 a5 cf 0f 0b e9 21 fb ff ff e8 c1 66 
[   60.735256] RSP: 0018:ffffb4c900513d60 EFLAGS: 00010282
[   60.735257] RAX: 0000000000000000 RBX: ffff9bcff2e60000 RCX: 0000000000000001
[   60.735258] RDX: 0000000080000001 RSI: ffffffff91086d8e RDI: 00000000ffffffff
[   60.735259] RBP: ffff9bcff2e60860 R08: 0000000000000000 R09: 0000000000000000
[   60.735260] R10: ffffb4c900513ca0 R11: ffffffff91244e98 R12: ffff9bcff2e60870
[   60.735261] R13: ffffffffc06d9751 R14: 0000000000000000 R15: 0000000000000000
[   60.735262] FS:  0000000000000000(0000) GS:ffff9bd01ea80000(0000) knlGS:0000000000000000
[   60.735263] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   60.735264] CR2: 00007f263401f9b8 CR3: 000000015e210006 CR4: 00000000001606e0
[   60.735265] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   60.735266] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   60.735267] Call Trace:
[   60.735271]  ? pci_pm_poweroff_late+0x30/0x30
[   60.735295]  ? i915_drm_suspend_late+0xda/0x130 [i915]
[   60.735298]  ? dpm_run_callback+0x61/0x320
[   60.735300]  ? __device_suspend_late+0xad/0x140
[   60.735302]  ? async_suspend_late+0x15/0x90
[   60.735304]  ? async_run_entry_fn+0x34/0x160
[   60.735306]  ? process_one_work+0x248/0x6c0
[   60.735308]  ? worker_thread+0x37/0x380
[   60.735310]  ? process_one_work+0x6c0/0x6c0
[   60.735312]  ? kthread+0x119/0x130
[   60.735314]  ? kthread_flush_work_fn+0x10/0x10
[   60.735316]  ? ret_from_fork+0x3a/0x50
[   60.735320] irq event stamp: 14756
[   60.735321] hardirqs last  enabled at (14755): [<ffffffff90956144>] _raw_spin_unlock_irq+0x24/0x50
[   60.735324] hardirqs last disabled at (14756): [<ffffffff9094ec3a>] __schedule+0xaa/0xbf0
[   60.735326] softirqs last  enabled at (14668): [<ffffffff90c0034f>] __do_softirq+0x34f/0x505
[   60.735328] softirqs last disabled at (14651): [<ffffffff900904f9>] irq_exit+0xa9/0xc0
[   60.735362] WARNING: CPU: 2 PID: 147 at drivers/gpu/drm/i915/intel_display.c:8965 hsw_enable_pc8+0x637/0x680 [i915]
[   60.735363] ---[ end trace b592869f28a8f147 ]---