[alsa-devel] [PATCH] ALSA: hda: Use loop counter for hdac_wait_for_cmd_dmas() timeout

[Takashi Iwai]

On Thu, 04 May 2017 12:30:32 +0200,
Vinod Koul wrote:
> 
> On Thu, May 04, 2017 at 12:25:26PM +0200, Takashi Iwai wrote:
> > On Thu, 04 May 2017 12:18:29 +0200,
> > Chris Wilson wrote:
> > > 
> > > hdac_wait_for_cmd_dmas() uses a jiffie timeout to ensure that we do not
> > > wait forever for stuck hardware. However, it is called from an
> > > irq-disabled context which prevents jiffie from advancing and so the
> > > loop doesn't terminate if the hardware fails. This can then cause NMI
> > > watchdog warnings, such as:
> > > 
> > >     NMI watchdog: Watchdog detected hard LOCKUP on cpu 3
> > >     Modules linked in: snd_hda_intel i915 vgem snd_hda_codec_hdmi x86_pkg_temp_thermal intel_powerclamp coretemp crct10dif_pclmul crc32_pclmul snd_hda_codec_realtek snd_hda_codec_generic ghash_clmulni_intel e1000e snd_hda_codec snd_hwdep snd_hda_core snd_pcm ptp mei_me prime_numbers pps_core mei lpc_ich i2c_hid i2c_designware_platform i2c_designware_core [last unloaded: i915]
> > >     irq event stamp: 13366
> > >     hardirqs last  enabled at (13365): [<ffffffff81891a87>] _raw_spin_unlock_irq+0x27/0x50
> > >     hardirqs last disabled at (13366): [<ffffffff818918d2>] _raw_spin_lock_irq+0x12/0x50
> > >     softirqs last  enabled at (12744): [<ffffffff81085c79>] __do_softirq+0x1d9/0x4c0
> > >     softirqs last disabled at (12721): [<ffffffff810860d9>] irq_exit+0xa9/0xc0
> > >     CPU: 3 PID: 10443 Comm: kworker/u8:11 Tainted: G     U          4.11.0-rc4-CI-CI_DRM_319+ #1
> > >     Hardware name:                  /NUC5i5RYB, BIOS RYBDWi35.86A.0362.2017.0118.0940 01/18/2017
> > >     Workqueue: events_unbound async_run_entry_fn
> > >     task: ffff88024cd32740 task.stack: ffffc9000162c000
> > >     RIP: 0010:preempt_count_add+0xe/0xc0
> > >     RSP: 0018:ffffc9000162fbd8 EFLAGS: 00000082
> > >     RAX: 0000000080000001 RBX: 0000000704b96558 RCX: 0000000000000002
> > >     RDX: 0000000000000000 RSI: ffffffff81c74f2d RDI: 0000000000000001
> > >     RBP: ffffc9000162fc08 R08: 00000000bbcc90cc R09: 23c7b07100000000
> > >     R10: ffffffff827901a8 R11: ffff88024cd32740 R12: 0000000704b92baa
> > >     R13: 0000000000003ea0 R14: 0000000000000003 R15: ffffffffa00061f0
> > >     FS:  0000000000000000(0000) GS:ffff880256d80000(0000) knlGS:0000000000000000
> > >     CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > >     CR2: 00007f90f84a5144 CR3: 0000000003e0f000 CR4: 00000000003406e0
> > >     Call Trace:
> > >      ? delay_tsc+0x3d/0xc0
> > >      __delay+0xa/0x10
> > >      __const_udelay+0x31/0x40
> > >      snd_hdac_bus_stop_cmd_io+0x96/0xe0 [snd_hda_core]
> > >      ? azx_dev_disconnect+0x20/0x20 [snd_hda_intel]
> > >      snd_hdac_bus_stop_chip+0xb1/0x100 [snd_hda_core]
> > >      azx_stop_chip+0x9/0x10 [snd_hda_codec]
> > >      azx_suspend+0x72/0x220 [snd_hda_intel]
> > >      pci_pm_suspend+0x71/0x140
> > >      dpm_run_callback+0x6f/0x330
> > >      ? pci_pm_freeze+0xe0/0xe0
> > >      __device_suspend+0xf9/0x370
> > >      ? dpm_watchdog_set+0x60/0x60
> > >      async_suspend+0x1a/0x90
> > >      async_run_entry_fn+0x34/0x160
> > >      process_one_work+0x1f4/0x6d0
> > >      ? process_one_work+0x16e/0x6d0
> > >      worker_thread+0x49/0x4a0
> > >      kthread+0x107/0x140
> > >      ? process_one_work+0x6d0/0x6d0
> > >      ? kthread_create_on_node+0x40/0x40
> > >      ret_from_fork+0x2e/0x40
> > > 
> > > Fixes: 38b19ed7f81e ("ALSA: hda: fix to wait for RIRB & CORB DMA to set")
> > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100419
> > > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > > Cc: Jeeja KP <jeeja.kp at intel.com>
> > > Cc: Vinod Koul <vinod.koul at intel.com>
> > > Cc: Takashi Iwai <tiwai at suse.de>
> > > Cc: <stable at vger.kernel.org> # v4.7+
> > 
> > Any reason to submit a different fix from what's attached in the
> > bugzilla you mentioned?
> 
> probably a race between then :)
> 
> Jeeja talked to me earlier today and uploaded the patch where we drop the
> locks and still use jiffies.
> 
> Takashi,
> Do you prefer dropping locks or using loop?

I prefer dropping the lock.


thanks,

Takashi