[alsa-devel] [PATCH] ALSA: hda - Disable Headphone Mic boost for ALC662

[Takashi Iwai]

At Thu, 28 May 2015 09:25:41 +0200,
David Henningsson wrote:
> 
> 
> 
> On 2015-05-28 09:18, Takashi Iwai wrote:
> > At Thu, 28 May 2015 09:15:46 +0200,
> > David Henningsson wrote:
> >>
> >> When headphone mic boost is above zero, some 10 - 20 second delay
> >> might occur before the headphone mic is operational.
> >> Therefore disable the headphone mic boost control (recording gain is
> >> sufficient even without it).
> >>
> >> (Note: this patch is not about the headset mic, it's about the less
> >> common mic-in only mode.)
> >>
> >> BugLink: https://bugs.launchpad.net/bugs/1454235
> >> Suggested-by: Kailang Yang <kailang at realtek.com>
> >> Signed-off-by: David Henningsson <david.henningsson at canonical.com>
> >> ---
> >>   sound/pci/hda/patch_realtek.c | 4 ++++
> >>   1 file changed, 4 insertions(+)
> >>
> >> diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
> >> index d0fa455..87605fc 100644
> >> --- a/sound/pci/hda/patch_realtek.c
> >> +++ b/sound/pci/hda/patch_realtek.c
> >> @@ -4240,6 +4240,10 @@ static void alc_fixup_headset_mode_alc662(struct hda_codec *codec,
> >>   	if (action == HDA_FIXUP_ACT_PRE_PROBE) {
> >>   		spec->parse_flags |= HDA_PINCFG_HEADSET_MIC;
> >>   		spec->gen.hp_mic = 1; /* Mic-in is same pin as headphone */
> >> +
> >> +		/* Disable boost for mic-in permanently */
> >> +		snd_hda_codec_write(codec, 0x1b, 0, AC_VERB_SET_AMP_GAIN_MUTE, 0x7000);
> >> +		snd_hda_override_wcaps(codec, 0x1b, get_wcaps(codec, 0x1b) & ~AC_WCAP_IN_AMP);
> >
> > Can we really hard-code NID 0x1b here...?
> 
> alc_fixup_headset_mode_alc662 is currently only called from a pin fixup 
> quirk (via ALC662_FIXUP_DELL_MIC_NO_PRESENCE), and that pin quirk has 
> headphone at 0x1b, so yes.

OK, then it'd be better to mention the assumption briefly in a
comment.

> It would we better if we could make it more generic, but I think doing 
> this at HDA_FIXUP_PROBE instead would be too late (the boost control, 
> paths, etc, would already be created)...?

Right.

> Do you have a better suggestion?

I think the current form is OK, but I wanted to make sure.


Takashi