[    5.669270] ------------[ cut here ]------------
[    5.673938] WARNING: CPU: 0 PID: 65 at drivers/gpu/drm/drm_atomic_helper.c:1386 drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0
[    5.685969] [CRTC:40:crtc-0] vblank wait timed out
[    5.690761] Modules linked in:
[    5.693819] CPU: 0 PID: 65 Comm: kworker/0:2 Tainted: G        W         4.18.0-g801ad8c-dirty #32
[    5.702762] Hardware name: Allwinner sun8i Family
[    5.707465] Workqueue: events output_poll_execute
[    5.712180] [<c010f020>] (unwind_backtrace) from [<c010ba80>] (show_stack+0x10/0x14)
[    5.719918] [<c010ba80>] (show_stack) from [<c0662f38>] (dump_stack+0x84/0x98)
[    5.727135] [<c0662f38>] (dump_stack) from [<c011dc54>] (__warn+0xfc/0x114)
[    5.734089] [<c011dc54>] (__warn) from [<c011dcb4>] (warn_slowpath_fmt+0x48/0x6c)
[    5.741565] [<c011dcb4>] (warn_slowpath_fmt) from [<c03f7e78>] (drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0)
[    5.752250] [<c03f7e78>] (drm_atomic_helper_wait_for_vblanks.part.1) from [<c03f7fcc>] (drm_atomic_helper_commit_tail_rpm+0x5c/0x6c)
[    5.764144] [<c03f7fcc>] (drm_atomic_helper_commit_tail_rpm) from [<c03f7f3c>] (commit_tail+0x40/0x6c)
[    5.773439] [<c03f7f3c>] (commit_tail) from [<c03f8138>] (drm_atomic_helper_commit+0xbc/0x130)
[    5.782041] [<c03f8138>] (drm_atomic_helper_commit) from [<c03fa918>] (restore_fbdev_mode_atomic+0x1cc/0x1dc)
[    5.791944] [<c03fa918>] (restore_fbdev_mode_atomic) from [<c03fe058>] (drm_fb_helper_restore_fbdev_mode_unlocked+0x4c/0xa4)
[    5.803145] [<c03fe058>] (drm_fb_helper_restore_fbdev_mode_unlocked) from [<c03fe0e0>] (drm_fb_helper_set_par+0x30/0x54)
[    5.813999] [<c03fe0e0>] (drm_fb_helper_set_par) from [<c03fdfcc>] (drm_fb_helper_hotplug_event.part.9+0x90/0xa8)
[    5.824246] [<c03fdfcc>] (drm_fb_helper_hotplug_event.part.9) from [<c03edc28>] (drm_kms_helper_hotplug_event+0x24/0x30)
[    5.835100] [<c03edc28>] (drm_kms_helper_hotplug_event) from [<c03edde8>] (output_poll_execute+0x188/0x1a0)
[    5.844828] [<c03edde8>] (output_poll_execute) from [<c0134e68>] (process_one_work+0x14c/0x410)
[    5.853515] [<c0134e68>] (process_one_work) from [<c013515c>] (worker_thread+0x30/0x59c)
[    5.861597] [<c013515c>] (worker_thread) from [<c013a888>] (kthread+0x120/0x150)
[    5.868985] [<c013a888>] (kthread) from [<c01010e8>] (ret_from_fork+0x14/0x2c)
[    5.876195] Exception stack(0xddc5dfb0 to 0xddc5dff8)
[    5.881240] dfa0:                                     00000000 00000000 00000000 00000000
[    5.889405] dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[    5.897569] dfe0: 00000000 00000000 00000000 00000000 00000013 00000000
[    5.904192] ---[ end trace 116c3dbc9981fad8 ]---
[....] Starting the hotplug events dispatcher: udevd[    6.152564] udevd[194]: starting version 175