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

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Date:   Wed, 22 Mar 2017 13:37:14 +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 4:59 PM, Bard Liao <bardliao@...ltek.com> wrote:
>> -----Original Message-----
>> From: Kai-Heng Feng [mailto:kai.heng.feng@...onical.com]
>> Sent: Tuesday, March 21, 2017 1:39 PM
>> To: Bard Liao
>> Cc: broonie@...nel.org; lgirdwood@...il.com; Oder Chiou;
>> alsa-devel@...a-project.org; linux-kernel@...r.kernel.org
>> Subject: Re: [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?
>
> It is different. rt5670_hp_event() is doing depop sequence for
> headphone. And there is no other mute/unmute controls on other
> dapm widgets. For me, what you do here is not different from
> "HPO L" and "HPO R" do.

There are two issues - background click noise and the cracking pop noise.
Depop is exactly what I want to do here.

>
>>
>> > "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.
>
> My point is that you seem to do things that driver is already done.
> But why and how it can reduce the click noise?

This is for the crack (pop) noise not click noise - see below.

>
>>
>> > 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.
>
> I didn't get it. How did you check if HPO is muted?

I didn't. Now sure why do we need to check that?

>
>>
>> > 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.
>
> Could you try only associated with "LDO2"?
> It makes sense that will reduce the noise if a jack is plugged in/out
> when HPO is already powered up.

Does it also help to reduce noise at other power events?

>
> I have question about the code below
> +               /* Fix headphone click noise */
> +               if (dmi_check_system(dmi_dell_dino))
> +                       regmap_write(rt286->regmap,
> +                                       RT286_MIC1_DET_CTRL, 0x0020);
> +
>
> What does this for? How did you get the value 0x0020?
> I just checked with Kailang, but he have no idea about that.

It's PIN_VREFHIZ. It's from commit 3e1b0c4a9d56.

>
>>
>> >
>> >
>>
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