Help request - ASoC recursion issue

Hi Mark,

I was wondering if I may bother you for some help. I've been having 
serious issues with testing the new mop500 sound system you have in your 
ASoC for-next branch. I've fixed a few issues and will be submitting 
patches shortly. The most serious issue I came across was with 
recursion. Let me show you:

So here we setup the power_check function pointer with 
'dapm_supply_check_power()'.

static struct snd_soc_dapm_widget *
snd_soc_dapm_new_control(struct snd_soc_dapm_context *dapm,
			 const struct snd_soc_dapm_widget *widget)
{

<snip>

	case snd_soc_dapm_regulator_supply:
	case snd_soc_dapm_clock_supply:
		w->power_check = dapm_supply_check_power;
		break;

<snip>

}

Later we call 'dapm_widget_power_check()' which calls into the function 
pointer we know to be 'dapm_supply_check_power()'.

 > static int dapm_widget_power_check(struct snd_soc_dapm_widget *w)
 > {
 > 	if (w->power_checked)
 > 		return w->new_power;
 >
 > 	if (w->force)
 > 		w->new_power = 1;
 > 	else
 > 		w->new_power = w->power_check(w);
 >
 > 	w->power_checked = true;
 >
 > 	return w->new_power;
 > }

The problem seems to be that 'dapm_supply_check_power()' then calls back 
into 'dapm_widget_power_check()'. Then round and round we go!

/* Check to see if a power supply is needed */
static int dapm_supply_check_power(struct snd_soc_dapm_widget *w)
{

<snip>

	/* Check if one of our outputs is connected */
	list_for_each_entry(path, &w->sinks, list_source) {
		DAPM_UPDATE_STAT(w, neighbour_checks);

		if (path->weak)
			continue;

		if (path->connected &&
		    !path->connected(path->source, path->sink))
			continue;

		if (!path->sink)
			continue;

		if (dapm_widget_power_check(path->sink))     /* <-- Doh! */
			return 1;
	}

<snip>

}

Can you shed some light on what the correct solution might be?

Any help would be gratefully received.

Kind regards,
Lee

-- 
Lee Jones
Linaro ST-Ericsson Landing Team Lead
Linaro.org ? Open source software for ARM SoCs
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