From mboxrd@z Thu Jan 1 00:00:00 1970 From: Timur Tabi Subject: Re: [PATCH 2/2] ASoC: DAPM - Make sure DAPM widget IO ops hold the component mutex. Date: Fri, 9 Mar 2012 13:11:26 -0600 Message-ID: <4F5A55DE.8020609@freescale.com> References: <1331057779-4630-1-git-send-email-lrg@ti.com> <1331057779-4630-2-git-send-email-lrg@ti.com> <1331316853.3789.4.camel@odin> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from ch1outboundpool.messaging.microsoft.com (ch1ehsobe001.messaging.microsoft.com [216.32.181.181]) by alsa0.perex.cz (Postfix) with ESMTP id 89206103B3C for ; Fri, 9 Mar 2012 20:11:43 +0100 (CET) In-Reply-To: <1331316853.3789.4.camel@odin> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: alsa-devel-bounces@alsa-project.org Errors-To: alsa-devel-bounces@alsa-project.org To: Liam Girdwood Cc: "alsa-devel@alsa-project.org" , Mark Brown List-Id: alsa-devel@alsa-project.org Liam Girdwood wrote: > Can you switch on the mutex debugging kernel config here. I've just had > a quick look and the WM8776 and its not holding the codec mutex or > calling snd_soc_update_bits_locked() so it must deadlock via another > path. Enabling the debug options didn't reveal anything, unfortunately. When I start playback, here's the code flow: dapm_seq_run_coalesced:1138 soc_widget_update_bits_locked:244 soc_widget_lock:211 codec=wm8776.1-001a platform= The numbers are line numbers of the printk statements I added. What happens is that the thread hangs on: mutex_lock(&w->codec->mutex); in soc_widget_lock(). After a couple minutes, I see this: INFO: task speaker-test:2624 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. speaker-test D 0fced718 0 2624 2623 0x00000000 Call Trace: [e6f27ab0] [c0038d5c] console_unlock+0x22c/0x29c (unreliable) [e6f27b70] [c0008520] __switch_to+0x70/0x144 [e6f27b90] [c04ab830] __schedule+0x224/0x4ec [e6f27be0] [c04aa6a8] mutex_lock_nested+0x188/0x394 [e6f27c40] [c0395c40] soc_widget_update_bits_locked+0x2b0/0x2c4 [e6f27c80] [c0397734] dapm_seq_run_coalesced.clone.24+0x1b8/0x1c4 [e6f27cc0] [c03977e4] dapm_seq_run.clone.25+0xa4/0x3c0 [e6f27d10] [c0397eb4] dapm_power_widgets+0x3b4/0x67c [e6f27d70] [c0399480] snd_soc_dapm_stream_event+0x74/0xdc [e6f27d90] [c039abb0] soc_pcm_prepare+0x108/0x1dc [e6f27dc0] [c0378248] snd_pcm_do_prepare+0x24/0x5c [e6f27dd0] [c0377e3c] snd_pcm_action_single+0x4c/0xb4 [e6f27df0] [c0379218] snd_pcm_action_nonatomic+0x7c/0xa0 [e6f27e10] [c037b678] snd_pcm_common_ioctl1+0x8f8/0x10d8 [e6f27e60] [c037c568] snd_pcm_playback_ioctl1+0x40/0x6cc [e6f27ea0] [c00f0e20] do_vfs_ioctl+0xa4/0x7d0 [e6f27f10] [c00f158c] sys_ioctl+0x40/0x88 [e6f27f40] [c000f6e4] ret_from_syscall+0x0/0x3c --- Exception: c01 at 0xfced718 LR = 0xfd76a24 INFO: lockdep is turned off. -- Timur Tabi Linux kernel developer at Freescale