WARNING: CPU: 0 PID: 124 at kernel/workqueue.c:3034 __flush_work+0x1be/0x1d0 -- hotplug before drm_dp_crc_register_connector
On an Acer TravelMate 5735Z with an Intel GMA 4500MHD, Linux 5.6.7 logged the warning below.
[ 1.158376] [drm] applying inverted panel brightness quirk
[ 1.158666] i915 0000:00:02.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=io+mem:owns=io+mem
[ 1.181859] ------------[ cut here ]------------
[ 1.181869] WARNING: CPU: 0 PID: 124 at kernel/workqueue.c:3034 __flush_work+0x1be/0x1d0
[ 1.181870] Modules linked in: i915(+) ahci i2c_algo_bit libahci drm_kms_helper libata psmouse cec scsi_mod evdev serio_raw drm video
[ 1.181881] CPU: 0 PID: 124 Comm: kworker/0:3 Not tainted 5.6.0-1-amd64 #1 Debian 5.6.7-1
[ 1.181883] Hardware name: Acer TravelMate 5735Z/BA51_MV, BIOS V1.14 07/26/2011
[ 1.182110] Workqueue: events i915_hotplug_work_func [i915]
[ 1.182114] RIP: 0010:__flush_work+0x1be/0x1d0
[ 1.182116] Code: 75 f1 eb e5 4c 8b 6d 20 e9 e5 fe ff ff 8b 0b 48 8b 53 08 83 e1 08 48 0f ba 2b 03 80 c9 f0 e9 47 ff ff ff 0f 0b e9 66 ff ff ff <0f> 0b 45 31 f6 e9 5c ff ff ff e8 03 f2 fd ff 0f 1f 00 66 66 66 66
[ 1.182117] RSP: 0018:ffffbc5c00183ba0 EFLAGS: 00010246
[ 1.182119] RAX: 0000000000000000 RBX: ffff9b95f6596688 RCX: 0000000000000019
[ 1.182120] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff9b95f6596688
[ 1.182121] RBP: 0000000000000001 R08: 0000000000000000 R09: ffffbc5c00183d38
[ 1.182122] R10: ffff9b95f6596000 R11: 0000000000000018 R12: ffff9b95f6596688
[ 1.182124] R13: ffff9b95f6464740 R14: 0000000000000001 R15: ffff9b95f6596000
[ 1.182125] FS: 0000000000000000(0000) GS:ffff9b95f7c00000(0000) knlGS:0000000000000000
[ 1.182127] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1.182128] CR2: 00005566b5386078 CR3: 00000000b4ed6000 CR4: 00000000000406f0
[ 1.182129] Call Trace:
[ 1.182138] ? acpi_ex_field_datum_io+0x10d/0x19d
[ 1.182143] ? acpi_ns_search_and_enter+0x156/0x1a8
[ 1.182145] __cancel_work_timer+0x107/0x190
[ 1.182150] ? ktime_get_mono_fast_ns+0x4e/0x90
[ 1.182179] drm_dp_cec_unset_edid+0x41/0xe0 [drm_kms_helper]
[ 1.182264] intel_dp_unset_edid+0x1d/0x40 [i915]
[ 1.182318] intel_dp_detect+0x3e2/0x4e0 [i915]
[ 1.182384] ? drm_modeset_lock+0x7b/0x100 [drm]
[ 1.182396] drm_helper_probe_detect_ctx+0x44/0xe0 [drm_kms_helper]
[ 1.182452] intel_encoder_hotplug+0x31/0x90 [i915]
[ 1.182506] intel_dp_hotplug+0x2d/0xb0 [i915]
[ 1.182512] ? __switch_to_asm+0x34/0x70
[ 1.182513] ? __switch_to_asm+0x40/0x70
[ 1.182515] ? __switch_to_asm+0x34/0x70
[ 1.182517] ? __switch_to_asm+0x40/0x70
[ 1.182537] ? drm_connector_list_iter_next+0x88/0xb0 [drm]
[ 1.182590] i915_hotplug_work_func+0x198/0x290 [i915]
[ 1.182593] process_one_work+0x1b4/0x380
[ 1.182595] worker_thread+0x50/0x3c0
[ 1.182600] kthread+0xf9/0x130
[ 1.182601] ? process_one_work+0x380/0x380
[ 1.182603] ? kthread_park+0x90/0x90
[ 1.182605] ret_from_fork+0x35/0x40
[ 1.182608] ---[ end trace 87e16baf2d72d531 ]---
[ 1.184079] [drm] Initialized i915 1.6.0 20200114 for 0000:00:02.0 on minor 0
[ 1.184232] probe of LNXVIDEO:00 returned 0 after 32 usecs
Edited by Chris Wilson