Hi Takashi,
I just got this deadlock when I tried to modprobe i915 on an ELK:
[ 203.716416] ============================================ [ 203.716417] WARNING: possible recursive locking detected [ 203.716418] 5.4.0-rc5-elk+ #206 Not tainted [ 203.716419] -------------------------------------------- [ 203.716420] kworker/0:1/12 is trying to acquire lock: [ 203.716421] efb1c138 (&spec->pcm_lock){+.+.}, at: generic_hdmi_init+0x21/0x140 [snd_hda_codec_hdmi] [ 203.716426] but task is already holding lock: [ 203.716427] efb1c138 (&spec->pcm_lock){+.+.}, at: check_presence_and_report+0x67/0xb0 [snd_hda_codec_hdmi] [ 203.716430] other info that might help us debug this: [ 203.716431] Possible unsafe locking scenario:
[ 203.716431] CPU0 [ 203.716432] ---- [ 203.716432] lock(&spec->pcm_lock); [ 203.716433] lock(&spec->pcm_lock); [ 203.716434] *** DEADLOCK ***
[ 203.716435] May be due to missing lock nesting notation
[ 203.716436] 3 locks held by kworker/0:1/12: [ 203.716436] #0: f14096a0 ((wq_completion)events){+.+.}, at: process_one_work+0x1b8/0x530 [ 203.716442] #1: f14dbf4c ((work_completion)(&bus->unsol_work)){+.+.}, at: process_one_work+0x1b8/0x530 [ 203.716444] #2: efb1c138 (&spec->pcm_lock){+.+.}, at: check_presence_and_report+0x67/0xb0 [snd_hda_codec_hdmi] [ 203.716448] stack backtrace: [ 203.716449] CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.4.0-rc5-elk+ #206 [ 203.716450] Hardware name: System manufacturer P5Q-EM/P5Q-EM, BIOS 2203 07/08/2009 [ 203.716457] Workqueue: events snd_hdac_bus_process_unsol_events [snd_hda_core] [ 203.716459] Call Trace: [ 203.716463] dump_stack+0x66/0x8e [ 203.716466] __lock_acquire.cold.62+0x3bf/0x3c7 [ 203.716468] ? mark_held_locks+0x3f/0x60 [ 203.716470] ? _raw_spin_unlock_irq+0x22/0x30 [ 203.716478] ? azx_rirb_get_response+0xd7/0x220 [snd_hda_codec] [ 203.716479] ? lockdep_hardirqs_on+0xec/0x1a0 [ 203.716480] ? _raw_spin_unlock_irq+0x22/0x30 [ 203.716483] ? trace_hardirqs_on+0x4a/0xf0 [ 203.716484] ? find_held_lock+0x26/0xb0 [ 203.716486] lock_acquire+0x74/0x150 [ 203.716488] ? generic_hdmi_init+0x21/0x140 [snd_hda_codec_hdmi] [ 203.716490] __mutex_lock+0x60/0x810 [ 203.716492] ? generic_hdmi_init+0x21/0x140 [snd_hda_codec_hdmi] [ 203.716496] ? snd_hdac_exec_verb+0x16/0x40 [snd_hda_core] [ 203.716499] ? codec_read+0x29/0x40 [snd_hda_core] [ 203.716501] mutex_lock_nested+0x14/0x20 [ 203.716503] ? generic_hdmi_init+0x21/0x140 [snd_hda_codec_hdmi] [ 203.716505] generic_hdmi_init+0x21/0x140 [snd_hda_codec_hdmi] [ 203.716507] generic_hdmi_resume+0x18/0x60 [snd_hda_codec_hdmi] [ 203.716512] hda_call_codec_resume+0xc2/0x130 [snd_hda_codec] [ 203.716517] hda_codec_runtime_resume+0x2a/0x60 [snd_hda_codec] [ 203.716520] __rpm_callback+0x7a/0x140 [ 203.716524] ? snd_hda_codec_device_new+0x2a0/0x2a0 [snd_hda_codec] [ 203.716529] ? snd_hda_codec_device_new+0x2a0/0x2a0 [snd_hda_codec] [ 203.716531] rpm_callback+0x1a/0x70 [ 203.716535] ? snd_hda_codec_device_new+0x2a0/0x2a0 [snd_hda_codec] [ 203.716537] rpm_resume+0x52c/0x700 [ 203.716538] ? _raw_spin_lock_irqsave+0x32/0x40 [ 203.716540] __pm_runtime_resume+0x43/0x90 [ 203.716543] snd_hdac_power_up_pm+0x4d/0x50 [snd_hda_core] [ 203.716546] hdmi_present_sense+0x34/0x340 [snd_hda_codec_hdmi] [ 203.716548] ? finish_task_switch+0x89/0x210 [ 203.716550] check_presence_and_report+0x7a/0xb0 [snd_hda_codec_hdmi] [ 203.716553] hdmi_unsol_event+0x57/0x60 [snd_hda_codec_hdmi] [ 203.716557] ? hda_codec_match+0x70/0x70 [snd_hda_codec] [ 203.716561] hda_codec_unsol_event+0x12/0x20 [snd_hda_codec] [ 203.716564] snd_hdac_bus_process_unsol_events+0x51/0x60 [snd_hda_core] [ 203.716566] process_one_work+0x230/0x530 [ 203.716567] worker_thread+0x37/0x410 [ 203.716569] kthread+0xf5/0x110 [ 203.716570] ? process_one_work+0x530/0x530 [ 203.716572] ? kthread_create_worker_on_cpu+0x20/0x20 [ 203.716574] ret_from_fork+0x2e/0x38
Looks like commit ade49db337a9 ("ALSA: hda/hdmi - Allow audio component for AMD/ATI and Nvidia HDMI") introduced pcm_lock to generic_hdmi_init().