[alsa-devel] No sound from internal speaker on 2013 Macbook Air 6, 1

[Takashi Iwai]

At Tue, 10 Sep 2013 01:48:05 +1000,
Ian Munsie wrote:
> 
> Hi Takashi,
> 
> > Check the value output by
> >
> >    hda-verb /dev/snd/hwC0D0 0x10 SET_PIN_SENSE 0
> >    hda-verb /dev/snd/hwC0D0 0x10 GET_PIN_SENSE 0
> >
> > before and after plugging the headphone.
> > Normally, the second line should show 0x80000000 after plugging the
> > jack.
> 
> Doesn't look like it:
> 
> ian at button~ [i]> sudo hda-verb /dev/snd/hwC0D0 0x10 SET_PIN_SENSE 0
> nid = 0x10, verb = 0x709, param = 0x0
> value = 0x0
> ian at button~ [i]> sudo hda-verb /dev/snd/hwC0D0 0x10 GET_PIN_SENSE 0
> nid = 0x10, verb = 0xf09, param = 0x0
> value = 0x0
> 
> <plug in headphones>
> 
> ian at button~ [i]> sudo hda-verb /dev/snd/hwC0D0 0x10 SET_PIN_SENSE 0
> nid = 0x10, verb = 0x709, param = 0x0
> value = 0x0
> ian at button~ [i]> sudo hda-verb /dev/snd/hwC0D0 0x10 GET_PIN_SENSE 0
> nid = 0x10, verb = 0xf09, param = 0x0
> value = 0x0

OK, then the normal jack detection doesn't work with this machine, as
it seems.  You can try the above to all pins for checking if any of
other pins reacts to the headphone jack.


> > If it shows only zero for both plug/unplug, either the headphone pin
> > assignment is wrong or the jack detection is broken.  In the former
> > case, you can check by adjusting the headphone volume or mute mixer
> > control and see whether it really happens on the machine.
> 
> I can confirm that adjusting the headphone volume & mute with
> alsamixer does correctly adjust the headphone volume, so I guess the
> jack detection isn't working.
> 
> It seems that pulseaudio was doing some funny things with the mute
> controls (muting any one of headphones, speakers & master would mute
> all three & all would have to be individually unmuted before getting
> sound again - I guess pulseaudio doesn't expect anyone to adjust the
> sound card mixer directly while it is running), so I temporarily
> uninstalled it again for this test.
> 
> 
> One other weird thing I noticed while testing this is that setting the
> volume to 0% and/or muting does the controls does not seem to
> completely mute the sound - it is just really quiet (quiet enough not
> to be an issue for me). Some observations:
> 
> __Speakers__
> Master: Mute AND/OR Speakers: Mute
> --> Speakers are muted.
> 
> Master: 0% AND Speakers: 0%
> --> Sound still comes from speakers, but is very quiet.
> 
> Master: 0%
> --> speaker control affects volume.
> 
> __Headphones__
> Master: 0% AND/OR Headphones: 0%
> --> Sound still comes from headphones at low volume
> (if either control is 0%, the volume of the other control has no
> effect - both have to be non-zero to raise the volume).
> 
> Master: Mute AND/OR Headphones: Mute
> --> Sound still comes from headphones, though is fairly quiet (much
> lower than 0%).

The volume 0% doesn't mean that the volume is muted.
But if the mute switch is set, it must mute the corresponding output.
If not, it means that the codec lies, or the actual output doesn't
come from the pin BIOS advertised.


Takashi