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

[Kai-Heng Feng]

On Tue, Mar 21, 2017 at 11:07 AM, Bard Liao <bardliao at realtek.com> wrote:
>> -----Original Message-----
>> From: Kai-Heng Feng [mailto:kai.heng.feng at canonical.com]
>> Sent: Monday, March 20, 2017 11:59 AM
>> To: broonie at kernel.org
>> Cc: lgirdwood at gmail.com; Bard Liao; Oder Chiou;
>> alsa-devel at alsa-project.org; linux-kernel at vger.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.

>
>