>> >>
>> >> >
>> >> > On a machine without fixed connecting audio devices like internal
>> >> > microphone or internal speaker, and when there is no external audio
>> >> > devices plugging in, the default source/sink is
alsa_input/alsa_output
>> >> > and there is no input devices/output devices listed in the gnome
>> >> > sound-setting.
>>
>> https://launchpadlibrarian.net/184055917/PulseList.txt
>>
>> Seem line in is active port when all ports are not available
>> Pulseaudio won't switch away from line in but gnome won't show line in
since it is not plugged
>>
>> ports:
>> analog-input-microphone-front: Front Microphone (priority 8500, latency
offset 0 usec, available: no)
>> properties:
>> device.icon_name = "audio-input-microphone"
>> analog-input-microphone-rear: Rear Microphone (priority 8200, latency
offset 0 usec, available: no)
>> properties:
>> device.icon_name = "audio-input-microphone"
>> analog-input-linein: Line In (priority 8100, latency offset 0 usec,
available: no)
>> properties:
>>
>> active port: <analog-input-linein>
>
> Yes, in this situation, the default-source->active_port->available=no, if
you use this module and pass "only_from_unavailable=yes", when connect
bluetooth headset, the default source will automatically switch to
bluez-source.
>
> In this situation, if you plug something in the line-in jack, the
default-source->active_port-available=yes, and if you pass
"only_from_unavailable=yes", the default source will not switch.
>>
>> https://launchpadlibrarian.net/184417469/alsa2.txt
>>
>>

>I do not have the hda-jack-sense-test command.

>I  was not aware that I was overriding the pcm.default. Is it worth
changing this to see if the bug goes away? How would I do that?

Seem upgrade does not remove previous conf

System wide config file (/etc/asound.conf)

###################### /etc/asound.conf ##################################
pcm.!default {
       type plug
       slave.pcm "asymed"
}

pcm.asymed {
       type asym
       playback.pcm "swmixer"
       capture.pcm "mixin"
}

pcm.dsp0 {
       type plug
       slave.pcm "asymed"
}

pcm.swmixer {
       type dmix
       ipc_key 1234
       slowptr yes
       slave {
               pcm "hw:0,0"
               period_time 0
               period_size 1024
               buffer_size 4096
               rate 48000
       }
}

ctl.dmixer {
       type hw
       card 0
}

pcm.mixin {
       type dsnoop
       ipc_key 5978293 # must be unique for all dmix plugins!!!!
       ipc_key_add_uid yes
       slave {
               pcm "hw:0,0"
               channels 2
               period_size 1024
               buffer_size 4096
               rate 48000
               periods 0
               period_time 0
       }
       bindings {
               0 0
               0 1
       }
}


> Do I need to build my own version of the kernel to disable jack detection?

https://launchpad.net/~diwic/+archive/ubuntu/hda

Install snd-hda-tools and run hda-jack-sense-test to find out whether rear
Mic Jack , line in and front Mic report correct Jack state when you plugged
and unplugged

If it work in windows, you may need to file an upstream bug report

If rear Mic Jack cannot report correct Jack state,

The workaround is disable Jack detection of rear Mic jack by hda-jack-retask