Re: [PATCH] ASoC: rt286: fix headphone click/crack noise on Dell XPS 9343 I2S mode

From: Mark Brown <broonie@kernel.org>
To: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: oder_chiou@realtek.com, bardliao@realtek.com,
	alsa-devel@alsa-project.org, lgirdwood@gmail.com
Subject: Re: [PATCH] ASoC: rt286: fix headphone click/crack noise on Dell XPS 9343 I2S mode
Date: Mon, 13 Mar 2017 13:30:52 +0000	[thread overview]
Message-ID: <20170313133052.vjw6vkrfbxvpdupa@sirena.org.uk> (raw)
In-Reply-To: <CAAd53p5LgLDfRbhHvwzN6KKhsqW+yHU-bKnyXKdciCXsu0Vq2Q@mail.gmail.com>

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On Mon, Mar 13, 2017 at 08:41:41AM +0000, Kai-Heng Feng wrote:
> On Fri, Feb 17, 2017 at 3:22 AM Mark Brown <broonie@kernel.org> wrote:

> > On Mon, Jan 23, 2017 at 01:35:14PM +0800, Kai-Heng Feng wrote:

> > > +static void dell_dino_mute_hpo(struct snd_soc_codec *codec)
> > > +{
> > > +     snd_soc_write(codec, RT286_SET_AMP_GAIN_HPO, AMP_OUT_MUTE);
> > > +}
> > > +

> > How does this ever get unmuted, should it be an _AUTODISABLE control
> > instead?

> I think the AMP is overrode by another value when playing sound, but I am
> not sure.

That's bad, we shouldn't have multiple inconsistent ways of controlling
the same thing - this tends to lead to bugs as they need to be
coordinated and things might change in one or both mechanisms.

> Can there be multiple callbacks hooked to the same widget?
> In this case, in addition to hpol_enable_control(), can I register another
> callback to "HPO L"?

You can have a callback that calls other callbacks to share code, you
can't do this directly in the framework itself.

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