From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jarkko Nikula <jhnikula@gmail.com>
Subject: Re: [PATCH] ASoC: Fix dapm_is_shared_kcontrol so
 everything isn't shared
Date: Thu, 26 May 2011 09:57:52 +0300
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On Wed, 25 May 2011 08:24:59 -0700
Stephen Warren <swarren@nvidia.com> wrote:

> > Then we must skip test for widgets that are in different dapm context,
> > i.e. we don't want to share mux controls if they are in different device
> > instance. Does it work for you if you add the dapm test below to your
> > patch?
> 
> I suppose that's technically correct, and I'm fine adding this to the
> patch. However, I'm surprised that change is needed; do we actually have
> a situation where two widgets in different DAPM contexts point at the
> same control definition? It seems like that'd be a bug; why would there
> be two controls pointing at the same register field, yet in different
> DAPM contexts?
> 
Yes, I noticed this can happen when you have multiple same codecs in a
system. Let's assume we have multiple wm8903 codecs and we have these
in the driver:

static const struct snd_kcontrol_new adcinput_mux =
	SOC_DAPM_ENUM("ADC Input", adcinput_enum);

static const struct snd_soc_dapm_widget wm8903_dapm_widgets[] = {
  SND_SOC_DAPM_MUX("Left ADC Input", SND_SOC_NOPM, 0, 0, &adcinput_mux),
};

Even the core duplicates widgets for each codec instance in this
example, they still point to same adcinput_mux and thus
dapm_is_shared_kcontrol() miss detects them as shared if we don't skip
different dapm context.

-- 
Jarkko