audio: rework modules, forward pipewire socket to gui-vm

[kajusnau]

Supersedes #1652

Description of Changes

Changes

• Reworked audio config:
  • Introduced server and client configs
  • audio-vm is now the server:
    • In charge of all audio HW
    • Main PipeWire instance runs here, along with 2 pipewire-pulse servers
  • All other systems are now clients
  • clients can optionally enable pw socket forwarding, which also needs to be enabled in the server
• Removed ghaf-audio namespace
• Removed ghaf-audio-control tool in favor of pavucontrol
• Restructured the ghaf.services.audio namespace
• Audio configuration is confined within the ghaf.services.audio namespace
• Removed all audio config from cosmic and gui-vm configs

New functionality

• pavucontrol (Volume Control in app library) app - added to gui-vm. Provides fine-grained volume and sound-related control for the entire system.
• Cosmic Settings Sound page - fully functional settings page for Output/Input device selection, volume control, device profile selection and more.

Topology:

graph TD
    %% Audio VM
    subgraph AudioVM["Audio VM"]
        subgraph PipeWire["PipeWire"]
            PWPulse1["PW Pulse server (restricted)"]
            PWPulse2["PW Pulse server (unrestricted)"]
        end
    end

    %% GUI VM
    subgraph GUIVM["GUI VM"]
        CosmicDE["System sounds"]
        Pavucontrol["pavucontrol"]
        CosmicSettings["Settings App"]
    end

    %% Other VMs
    subgraph VM1["Comms VM"]
        Slack["Slack"]
    end

    subgraph VM2["Chrome VM"]
        Chrome["Chrome"]
    end

    %% Connections

    %% GUI VM audio (unrestricted)
    CosmicDE -->|"PULSE_SERVER"| PWPulse2
    Pavucontrol -->|"PULSE_SERVER"| PWPulse2

    %% GUI VM control (PipeWire socket)
    CosmicSettings <-.->|"PipeWire socket (via givc)"| PipeWire

    %% Other VMs audio (restricted)
    Slack -->|"PULSE_SERVER"| PWPulse1
    Chrome -->|"PULSE_SERVER"| PWPulse1

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Known Issues

• Plugging in 3.5mm device might not automatically select the 3.5mm headphone profile.
  This can still be done manually via Cosmic Settings -> Sound -> Device Profiles
• Changing the input device via the settings page or the applet may sometimes reset to the previously selected device:
  • e.g. Changing from "Digital Microphone" to "Stereo Microphone" and then adjusting Microphone volume might result in the input device being changed back to "Digital Microphone" automatically. Cause unknown as of yet.
  • Can be avoided entirely if changing the input device via "PipeWire Volume Control (pwvucontrol)" app
• Adjusting volume with keyboard shortcuts may cause cosmic-settings-daemon or cosmic-osd to spike to 100% CPU usage.
  Upstream bug. cosmic-osd will be re-started automatically if this happens, but cosmic-settings-daemon will not.

Type of Change

• New Feature
• Bug Fix
• Improvement / Refactor

Related Issues / Tickets

Checklist

• Clear summary in PR description
• Detailed and meaningful commit message(s)
• Commits are logically organized and squashed if appropriate
• Contribution guidelines followed
• Ghaf documentation updated with the commit - https://tiiuae.github.io/ghaf/
• Author has run make-checks and it passes
• All automatic GitHub Action checks pass - see actions
• Author has added reviewers and removed PR draft status

Testing Instructions

Applicable Targets

• Orin AGX aarch64
• Orin NX aarch64
• Lenovo X1 x86_64
• Dell Latitude x86_64
• System 76 x86_64

Installation Method

• Requires full re-installation
• Can be updated with nixos-rebuild ... switch
• Other:

Test Steps To Verify:

1. Verify all audio related functionality works as expected, including but not limited to:
   • Verify audio devices appear and can be freely managed in the cosmic-applet-audio applet and cosmic-settings
   • Verify volume adjustment keyboard shortcuts work as expected
2. Investigate CPU usage problems while adjusting audio:
   1. In gui-vm run htop and observe CPU usage
   2. Adjust volume via applet, keyboard shortcuts, or otherwise; play/pause audio; change audio devices;
   3. Ensure CPU usage for any one process does not stay at 100% for an extended period of time (offending processes should be automatically killed and restarted within ~30s (except cosmic-settings-daemon, which cannot be restarted))
3. Verify screen recording works as before via ghaf-screen-record or the keyboard shortcut (SHIFT+ALT+CTRL+R)

[milva-unikie]

I did a quick round of testing on Darter Pro

• Integrated audio devices are working well
• USB headset works
• With 3.5 mm and Bluetooth headsets the audio output works but microphones don't work

[milva-unikie]

TL;DR: all good ✅

Tested on Darter Pro (new installation)

• Integrated, USB, 3.5 mm and Bluetooth audio devices all work.
• Audio controls in the applet, Cosmic Settings and Volume Control (pavucontrol) work.
• Keyboard shortcuts for changing the volume work.
• After all testing there were no processes using 100 % CPU.
• Screen recording works.
• From the Known issues I noticed that adjusting the volume from the audio applet sometimes does not work with USB or 3.5 mm audio devices. Keyboard shortcuts work in these situations and re-plugging the device fixes the issue.

Tested on Lenovo X1 (new installation)

• Integrated, USB, 3.5 mm and Bluetooth audio devices all work.

There are failures in the jenkins-pre-merge pipeline because the process name of cosmic-settings changes. A fix for that in tiiuae/ci-test-automation#620, needs to be merged together with this PR (@brianmcgillion)