From a390500309cce52b90aa37efa6aeadef9d06b455 Mon Sep 17 00:00:00 2001
From: Stefan Agner <stefan@agner.ch>
Date: Mon, 23 Oct 2023 21:57:57 +0200
Subject: [PATCH] Reload Pulseaudio modules on hardware change (#4638)

* Reload Pulseaudio modules on hardware change

In the past the audio plug-in restarted Pulseaudio on hardware change.
This broke with the s6 updates. However, it also turns out that this is
quite racy: The Supervisor reloads audio data much too quickly, when
Supervisor isn't restarted yet.

Instead, let's reload the relevant modules from Supervisor itself.

This works well with a USB microphone on Home Assistant Green.

Related change: https://github.com/home-assistant/plugin-audio/pull/153

* Fix linter issue
---
 supervisor/host/manager.py |  2 +-
 supervisor/host/sound.py   | 30 +++++++++++++++++++++++++++---
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/supervisor/host/manager.py b/supervisor/host/manager.py
index af7efce23..a9d858e96 100644
--- a/supervisor/host/manager.py
+++ b/supervisor/host/manager.py
@@ -175,4 +175,4 @@ class HostManager(CoreSysAttributes):
     async def _hardware_events(self, device: Device) -> None:
         """Process hardware requests."""
         if self.sys_hardware.policy.is_match_cgroup(PolicyGroup.AUDIO, device):
-            await self.sound.update()
+            await self.sound.update(reload_pulse=True)
diff --git a/supervisor/host/sound.py b/supervisor/host/sound.py
index 8413c349c..4f64e952a 100644
--- a/supervisor/host/sound.py
+++ b/supervisor/host/sound.py
@@ -15,6 +15,9 @@ _LOGGER: logging.Logger = logging.getLogger(__name__)
 
 PULSE_NAME = "supervisor"
 
+PULSE_ALSA_MODULE = "module-alsa-card"
+PULSE_UDEV_MODULE = "module-udev-detect"
+
 
 class StreamType(StrEnum):
     """INPUT/OUTPUT type of source."""
@@ -235,9 +238,9 @@ class SoundControl(CoreSysAttributes):
     @Job(
         name="sound_control_update",
         limit=JobExecutionLimit.THROTTLE_WAIT,
-        throttle_period=timedelta(seconds=10),
+        throttle_period=timedelta(seconds=2),
     )
-    async def update(self):
+    async def update(self, reload_pulse: bool = False):
         """Update properties over dbus."""
         _LOGGER.info("Updating PulseAudio information")
 
@@ -348,11 +351,32 @@ class SoundControl(CoreSysAttributes):
                     f"Error while processing pulse update: {err}", _LOGGER.error
                 ) from err
             except PulseError as err:
-                _LOGGER.debug("Can't update PulseAudio data: %s", err)
+                _LOGGER.warning("Can't update PulseAudio data: %s", err)
 
             return data
 
+        def _reload_pulse_modules():
+            try:
+                with Pulse(PULSE_NAME) as pulse:
+                    modules = pulse.module_list()
+                    for alsa_module in filter(
+                        lambda x: x.name == PULSE_ALSA_MODULE, modules
+                    ):
+                        pulse.module_unload(alsa_module.index)
+                    udev_module = next(
+                        filter(lambda x: x.name == PULSE_UDEV_MODULE, modules)
+                    )
+                    pulse.module_unload(udev_module.index)
+                    # And now reload
+                    pulse.module_load(PULSE_UDEV_MODULE)
+            except StopIteration:
+                _LOGGER.warning("Can't reload PulseAudio modules.")
+            except PulseError as err:
+                _LOGGER.warning("Can't reload PulseAudio modules: %s", err)
+
         # Update data from pulse server
+        if reload_pulse:
+            await self.sys_run_in_executor(_reload_pulse_modules)
         data: PulseData = await self.sys_run_in_executor(_get_pulse_data)
         self._applications = data.applications
         self._cards = data.cards