[alsa-devel] snd-hda-intel : issues with mic boost on ALC3236

[Takashi Iwai]

At Wed, 29 Apr 2015 22:26:39 +0200,
Simon Derr wrote:
> 
> >> I'm having issues with the internal microphone on an Asus R553 (or S551) laptop.
> >>
> >> With the boost set to zero the microphone works but the level of the
> >> recording is very low.
> >> If I try another boost setting I don't get any signal anymore.
> 
> > The problem is unlikely specific to the codec (ALC3236) but the whole
> > hardware implementation.
> 
> I have to admit that I have zero knowledge of how these things are
> implemented. I can't find a datasheet for that codec anywhere.
> However, looking at the ALC262 datasheet for instance, the block
> diagram represents the boost function inside the codec itself.

ALC3236 isn't ALC262 but rather ALC269 variant.

Kailang, is there anything special in ALC3236 regarding the mic boost
handling?  Here, the problem is that the machine doesn't get builtin
mic working when mic boost is set more than 0, and 0 gives only low
signals.  alsa-info.sh is at:
  http://www.alsa-project.org/db/?f=55b7fb0b4998757d099addae0a411e6a7cebc079

> > Your hardware seems to have only one mic pin.  It's already strange.
> > Usually there are two mic pins.  Did you try the input from mic jack
> > (or headset mic)?   Did it work with mic boot volume properly?
> 
> I just tried : plugging a headset in the combo jack does not seem to
> have any effect on the mic input. It seems that the mic on the headset
> is not used, and that the internal microphone of the laptop is still
> active.

So you have two problems.  Not sure whether it's related, though.

You may try some existing quirk for Dell laptops,
e.g. model=dell-headset-multi.  In your case, the realtek codec is the
second one, so pass "model=,dell-headset-multi" (give a comma at first)


Takashi