linux-kernel - Re: [PATCH v3] ASoC: rt286: fix headphone click/crack noise on Dell XPS 9343 I2S mode

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Message-ID: <CAAd53p6rzVtV7kiBpChrHrrpTG1RhTiQbOZVU+wC1rFWeb=5ow@mail.gmail.com>
Date:   Tue, 21 Mar 2017 13:38:55 +0800
From:   Kai-Heng Feng <kai.heng.feng@...onical.com>
To:     Bard Liao <bardliao@...ltek.com>
Cc:     "broonie@...nel.org" <broonie@...nel.org>,
        "lgirdwood@...il.com" <lgirdwood@...il.com>,
        Oder Chiou <oder_chiou@...ltek.com>,
        "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3] ASoC: rt286: fix headphone click/crack noise on Dell
 XPS 9343 I2S mode

On Tue, Mar 21, 2017 at 11:07 AM, Bard Liao <bardliao@...ltek.com> wrote:
>> -----Original Message-----
>> From: Kai-Heng Feng [mailto:kai.heng.feng@...onical.com]
>> Sent: Monday, March 20, 2017 11:59 AM
>> To: broonie@...nel.org
>> Cc: lgirdwood@...il.com; Bard Liao; Oder Chiou;
>> alsa-devel@...a-project.org; linux-kernel@...r.kernel.org; Kai-Heng Feng
>> Subject: [PATCH v3] ASoC: rt286: fix headphone click/crack noise on Dell XPS
>> 9343 I2S mode
>>
>> +     switch (event) {
>> +     case SND_SOC_DAPM_PRE_PMD:
>> +     case SND_SOC_DAPM_POST_PMD:
>> +     case SND_SOC_DAPM_POST_PMU:
>> +             snd_soc_write(codec, RT286_SET_AMP_GAIN_HPO,
>> AMP_OUT_MUTE);
>> +             break;
>> +     case SND_SOC_DAPM_PRE_PMU:
>> +             snd_soc_write(codec, RT286_SET_AMP_GAIN_HPO,
>> AMP_OUT_UNMUTE);
>> +             break;
>
> Besides Mark's comment, I have question here. It seems you want to mute
> HPO before "HP Power" is powered up and after "HP Power" is powered down.
> But "HPO L" and "HPO R" are autodisable. And "HP Power" is only connect to

What I really want to do is something rt5670's rt5670_hp_event(),
maybe autodisable is not enough sometimes?

> "HPO L" and "HPO R". From my understanding, HPO will mute if "HP Power"
> is powered down. Any specific reason for muting HPO again before "HP Power"
> is powered up?

You are right. Either one of them should be sufficient.

> Will HPO be unmuted before "HP Power" is powered up on your system?

Yes.
I am no audio expert here - but from what I read from HDA, there's
actually no AMP unmute counterpart to AMP mute.

> Or should the event be associated with "LDO1"?  Which power will
> cause the click noise?

I found that the effect is most noticeable if the mute callback is
associated with "LDO2" and "HP Power".
But again, this is just what I observed.

>
>