internal speaker not list in sound setting when external audio device is conneceted

[jeremyszu]

[Summary]
internal speaker not list in sound setting when external device is connected

[Steps to reproduce]
1) check sound setting, internal speak is listed in sound setting --> output device
2) plug a headset in 3.5mm headphone jack (front port)
3) check sound setting
4) plug headset in line-out port
5) check sound setting

[Expected result]
internal speaker should list when external audio device is connected.

[Actual result]
plug a headset in 3.5mm headphone jack (front port) --> headphone and HDMI/DP audio are listed, no internal speaker
plug a headset in line-out port --> Line-out and HDMI/DP audio are listed, no internal speaker
plug a headset in 3.5mm headphone jack (front port) and a headset in line-out port --> headphone, Line-out and HDMI/DP audio are listed, no internal speaker

---

$ lsb_release -rd
Description: Ubuntu 20.04.3 LTS
Release: 20.04

$ apt-cache policy pulseaudio
pulseaudio:
  Installed: 1:13.99.1-1ubuntu3.12
  Candidate: 1:13.99.1-1ubuntu3.12
  Version table:
 *** 1:13.99.1-1ubuntu3.12 500
        500 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     1:13.99.1-1ubuntu3.8 500
        500 http://security.ubuntu.com/ubuntu focal-security/main amd64 Packages
     1:13.99.1-1ubuntu3 500
        500 http://archive.ubuntu.com/ubuntu focal/main amd64 Packages

[jeremyszu (os369510)]

Update from https://bugs.launchpad.net/stella/+bug/1948777:

1) ---
The Speaker in general doesn't have corresponding jack, so its availability is "unknown".
When it's legacy HDA, once a Headphone is plugged, PulseAudio will disable all "unknown" profiles, so the speaker is gone in this case.

When it's DMIC, the disablement of "unknown" profile is skipped because it's using UCM.

2) ---
The headset jack plug may or may not have ability to determine jack type (i.e. what gets plugged in), and that creates two different behaviors:

- When the hardware can determine jack types like most HP and Lenovo hardwares, libgnome-volume-control checks PA status and switches to corresponding device

- When the hardware _cannot_ determine jack types like most Dell hardwares, libgnome-volume-control leaves all possible option available. For instance, when something gets plugged in, the system doesn't know it's headphone, mic, or a headset, so it has to leave all options to the user and user is responsible to choose the right device.