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From: "Pan, Harry" <harry.pan@intel.com>
To: "lars@metafoo.de" <lars@metafoo.de>,
	"broonie@kernel.org" <broonie@kernel.org>
Cc: "lgirdwood@gmail.com" <lgirdwood@gmail.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"gs0622@gmail.com" <gs0622@gmail.com>,
	"alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
	"tiwai@suse.com" <tiwai@suse.com>,
	"perex@perex.cz" <perex@perex.cz>
Subject: Re: [PATCH] ASoC: dapm: Do not traverse widget hooks to snd-soc-dummy
Date: Thu, 17 Mar 2016 13:04:15 +0000	[thread overview]
Message-ID: <1458219853.24844.10.camel@intel.com> (raw)
In-Reply-To: <56EAA4FC.5090408@metafoo.de>

> I'd say as a quick fix for stable check that card is not NULL in
> dapm_widget_show_component(). And as a longterm fix get rid of
> dapm_widget
> file. Nobody should hopefully use it anymore with debugfs being
> available as
> the far better alternative.
> 
> - Lars

Well, that was my original approach while I realized problem
is caused by de-referencing a null pointer to its member of
'widget' list.

i.e.
https://chromium-review.googlesource.com/#/c/331285/3/sound/soc/soc-dap
m.c

+   if (WARN_ON(!codec->component.card))
+       return 0;
+

Additional remark is that I was working on chromium-os v3.18 kernel,
so that the interface and argument are sort of different than what
I then cherry-pick'ed then sent, which was based on latest 4.5.

Then I was stuck at here couple days keeping hunting root cause,
Turned out I found that commit skipped probing dummy component.

Long story short.

-Harry

  reply	other threads:[~2016-03-17 13:04 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-16 11:17 [PATCH] ASoC: dapm: Do not traverse widget hooks to snd-soc-dummy Harry Pan
2016-03-17  9:54 ` Mark Brown
2016-03-17 10:38   ` Pan, Harry
2016-03-17 11:25     ` Mark Brown
2016-03-17 12:37       ` Lars-Peter Clausen
2016-03-17 13:04         ` Pan, Harry [this message]
2016-03-17 15:42         ` Mark Brown
2016-03-18  5:17           ` [alsa-devel] " Vinod Koul
  -- strict thread matches above, loose matches on Subject: below --
2016-03-16 10:43 Harry Pan

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