linux-kernel - Re: [PATCH v2 2/2] ASoC: fsl: imx-wm8962: Grant hw

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Message-ID: <20131210102523.GB12042@MrMyself>
Date:	Tue, 10 Dec 2013 18:25:24 +0800
From:	Nicolin Chen <Guangyu.Chen@...escale.com>
To:	Mark Brown <broonie@...nel.org>
CC:	Nicolin Chen <b42378@...escale.com>, <lgirdwood@...il.com>,
	<alsa-devel@...a-project.org>, <tiwai@...e.de>, <perex@...ex.cz>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/2] ASoC: fsl: imx-wm8962: Grant hw_params/free()
 permission to control FLL

On Tue, Dec 10, 2013 at 01:18:42PM +0800, Nicolin Chen wrote:
> On Mon, Dec 09, 2013 at 05:56:40PM +0000, Mark Brown wrote:
> > On Fri, Dec 06, 2013 at 11:38:29PM +0800, Nicolin Chen wrote:
> > 
> > > +static int imx_hifi_hw_free(struct snd_pcm_substream *substream)
> > > +{
> > > +	struct snd_soc_pcm_runtime *rtd = substream->private_data;
> > > +	struct snd_soc_dai *codec_dai = rtd->codec_dai;
> > > +
> > > +	/* Don't diable FLL if still having multiple substreams running */
> > > +	if (codec_dai->active != 1)
> > > +		return 0;
> > > +
> > > +	return imx_wm8962_disable_fll(codec_dai);
> > 
> > This will still disable the FLL if there's an analogue bypass path
> > active.  I'd suggest changing enable() and disable() to reference count.
> 
> I was expecting this would disable it for further reconfiguration. But it
> seems I should also considerate the case using bypass path and normal PCM
> playback simultaneously, which looks a bit complex.

Hmm...Sorry for asking a stupid question that how to test bypass path with
WM8962? I've tried some amixer commands to enable the bypass-path switches.
But we still need to power the Codec up like using arecord or aplay to call
wm8962_resume() and DAPM-related, right?

Sir, could you please share a simple flow for user space so that I can test
and make the patch more comprehensive?

Thank you,
Nicolin Chen

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