[alsa-devel] [PATCH] ALSA: hda - Add a de-pop quirk for some HP machines

[hwang4]

On 2014年08月29日 16:02, Takashi Iwai wrote:
> At Fri, 29 Aug 2014 15:47:05 +0800,
> Hui Wang wrote:
>> On some HP machines, there will be pop noise when the machine is
>> shutting down, rebooting or booting up from poweroff state.
>>
>> Set EAPD enable only when stream starts can help to fix this
>> problem.
>>
>> [The patch was originally written by Kailang, we tested it and
>> rebased it on latest kernel.]
>>
>> Signed-off-by: Kailang Yang <kailang at realtek.com>
>> Signed-off-by: Hui Wang <hui.wang at canonical.com>
>> ---
>>   sound/pci/hda/patch_realtek.c | 55 ++++++++++++++++++++++++++++++++++++++++---
>>   1 file changed, 52 insertions(+), 3 deletions(-)
>>
>> diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
>> index 48d6d10..51811a6 100644
>> --- a/sound/pci/hda/patch_realtek.c
>> +++ b/sound/pci/hda/patch_realtek.c
>> @@ -4282,6 +4282,47 @@ static void alc290_fixup_mono_speakers(struct hda_codec *codec,
>>   	}
>>   }
>>   
>> +/*
>> + * ALC290 PCM hooks
>> + */
>> +static void alc290_playback_pcm_hook(struct hda_pcm_stream *hinfo,
>> +				     struct hda_codec *codec,
>> +				     struct snd_pcm_substream *substream,
>> +				     int action)
>> +{
>> +	int val;
>> +
>> +	switch (action) {
>> +	case HDA_GEN_PCM_ACT_OPEN:
>> +		val = alc_read_coef_idx(codec, 0x4); /* EAPD manual high */
>> +		if ((val & 0xc000) != 0xc000)
>> +			alc_write_coef_idx(codec, 0x4, val | (1<<14));
>> +		break;
>> +	}
>> +}
>> +
>> +static void alc290_fixup_pop_noise(struct hda_codec *codec,
>> +				   const struct hda_fixup *fix, int action)
>> +{
>> +	struct alc_spec *spec = codec->spec;
>> +	int val;
>> +
>> +	switch (action) {
>> +	case HDA_FIXUP_ACT_PRE_PROBE:
>> +		snd_hda_codec_write(codec, 0x17, 0,
>> +				    AC_VERB_SET_PIN_WIDGET_CONTROL, PIN_OUT);
> Why do you need this...
>
>> +		val = alc_read_coef_idx(codec, 0x4);
>> +		if ((val & 0xc000) != 0xc000)
>> +			alc_write_coef_idx(codec, 0x4, val | (3<<14)); /* EAPD low */
>> +		spec->gen.pcm_playback_hook = alc290_playback_pcm_hook;
>> +		break;
>> +	case HDA_FIXUP_ACT_INIT:
>> +		snd_hda_codec_write(codec, 0x17, 0,
>> +				    AC_VERB_SET_PIN_WIDGET_CONTROL, PIN_OUT);
> ... and this?  There is no explanation about this change.
>
> Also, can't you just set EAPD low in the shutdown callback instead?
Good idea, all will be addressed in the V2.

Thanks,
Hui.
> In your patch, if the machine goes shutdown/reboot while playing a
> stream (or before runtime PM), it's still EAPD high, so the noise
> should be heard, if I understand correctly.
>
>
> Takashi
>
>