Re: [PATCH] ALSA: hda: Use loop counter for hdac_wait_for_cmd_dmas() timeout

From: Takashi Iwai <tiwai@suse.de>
To: Chris Wilson <chris@chris-wilson.co.uk>
Cc: alsa-devel@alsa-project.org, intel-gfx@lists.freedesktop.org,
	Jeeja KP <jeeja.kp@intel.com>, Vinod Koul <vinod.koul@intel.com>,
	"# v4 . 7+" <stable@vger.kernel.org>
Subject: Re: [PATCH] ALSA: hda: Use loop counter for hdac_wait_for_cmd_dmas() timeout
Date: Thu, 04 May 2017 12:25:26 +0200	[thread overview]
Message-ID: <s5h60hgq5pl.wl-tiwai@suse.de> (raw)
In-Reply-To: <20170504101829.28325-1-chris@chris-wilson.co.uk>

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@chris-wilson.co.uk>
> Cc: Jeeja KP <jeeja.kp@intel.com>
> Cc: Vinod Koul <vinod.koul@intel.com>
> Cc: Takashi Iwai <tiwai@suse.de>
> Cc: <stable@vger.kernel.org> # v4.7+

Any reason to submit a different fix from what's attached in the
bugzilla you mentioned?

thanks,

Takashi

> ---
>  sound/hda/hdac_controller.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/sound/hda/hdac_controller.c b/sound/hda/hdac_controller.c
> index ee08c389b4d6..7f8806b03982 100644
> --- a/sound/hda/hdac_controller.c
> +++ b/sound/hda/hdac_controller.c
> @@ -85,14 +85,14 @@ static void hdac_wait_for_cmd_dmas(struct hdac_bus *bus)
>  {
>  	unsigned long timeout;
>  
> -	timeout = jiffies + msecs_to_jiffies(100);
> +	timeout = 100 * 100; /* 100ms */
>  	while ((snd_hdac_chip_readb(bus, RIRBCTL) & AZX_RBCTL_DMA_EN)
> -		&& time_before(jiffies, timeout))
> +	       && timeout--)
>  		udelay(10);
>  
> -	timeout = jiffies + msecs_to_jiffies(100);
> +	timeout = 100 * 100; /* 100ms */
>  	while ((snd_hdac_chip_readb(bus, CORBCTL) & AZX_CORBCTL_RUN)
> -		&& time_before(jiffies, timeout))
> +	       && timeout--)
>  		udelay(10);
>  }
>  
> -- 
> 2.11.0
> 