[alsa-devel] [PATCH v3] ASoC: dapm - Add API call to query the widgets of valid DAPM paths.

Mark Brown broonie at opensource.wolfsonmicro.com
Mon Jul 25 23:16:20 CEST 2011

On Mon, Jul 25, 2011 at 11:15:26AM +0100, Liam Girdwood wrote:

> +int snd_soc_dapm_get_connected_widgets(struct snd_soc_dapm_context *dapm,
> +	const char *stream_name, struct snd_soc_dapm_widget_list **list,
> +	int stream)

> +	/* get stream root widget AIF from stream string and direction */
> +	list_for_each_entry(w, &dapm->card->widgets, list) {
> +
> +		if (w->id != type)
> +			continue;
> +
> +		if (!strcmp(w->sname, stream_name))
> +			goto found;
> +	}

Hrm, so I must be missing something here but this still has the issue
with only finding the first widget if we've got more than one widget for
a stream.  For example, the tlv320aic3x driver defines:

   SND_SOC_DAPM_DAC("Left DAC", "Left Playback", DAC_PWR, 7, 0),
   SND_SOC_DAPM_DAC("Right DAC", "Right Playback", DAC_PWR, 6, 0),

and hooks them both up to a single "Playback" stream (most devices don't
even have the distinct names at the widget level).  This makes sense as
DAPM really does want mono streams to work with but if we only look at
the first match we'll fail to enumerate some of the widgets connected to
the stream.  I think the found: block wants to be inside the if
statement and probably just drop the dev_err(), or do it by checking to
see if the list we come up with is empty.

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