d/patches: Add fallback sink script

When running PW/WP on board with only HDMI audio output, and this one is
not connected, PW fails to create the Dummy Output as policy endpoint are
created by WP.

Signed-off-by: Frédéric Danis <frederic.danis@collabora.com>

debian/patches/0001-scripts-Add-script-to-create-fallback-sink.patch

+From 57769c20715873a06a756494f50bd2c6a9c71bea Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Danis?= <frederic.danis@collabora.com>
+Date: Thu, 31 Mar 2022 14:57:20 +0200
+Subject: [PATCH] scripts: Add script to create fallback sink
+Content-Type: text/plain; charset="utf-8"
+Content-Transfer-Encoding: 8bit
+
+This script, base on PipeWire module fallback-sink will create a fallback
+sink node if there's no other sink available except the endpoints created
+by WirePlumber.
+---
+ src/scripts/fallback-sink.lua | 93 +++++++++++++++++++++++++++++++++++
+ 1 file changed, 93 insertions(+)
+ create mode 100644 src/scripts/fallback-sink.lua
+
+diff --git a/src/scripts/fallback-sink.lua b/src/scripts/fallback-sink.lua
+new file mode 100644
+index 0000000..d7c3cfa
+--- /dev/null
++++ b/src/scripts/fallback-sink.lua
+@@ -0,0 +1,93 @@
++-- WirePlumber
++--
++-- Copyright © 2021 Collabora Ltd.
++--    @author Frédéric Danis <frederic.danis@collabora.com>
++--
++-- SPDX-License-Identifier: MIT
++
++local sink_ids = {}
++local fallback_node = nil
++
++node_om = ObjectManager {
++  Interest {
++    type = "node",
++    Constraint { "media.class", "matches", "Audio/Sink", type = "pw-global" },
++    -- Do not consider endpoints created by WirePlumber
++    Constraint { "wireplumber.is-endpoint", "!", true, type = "pw" },
++    -- or the fallback sink itself
++    Constraint { "wireplumber.is-fallback", "!", true, type = "pw" },
++  }
++}
++
++function createFallbackSink()
++  if fallback_node then
++    return
++  end
++
++  Log.info("Create fallback sink")
++
++  local properties = {}
++
++  properties["node.name"] = "auto_null"
++  properties["node.description"] = "Dummy Output"
++
++  properties["audio.rate"] = 48000
++  properties["audio.channels"] = 2
++  properties["audio.position"] = "FL,FR"
++
++  properties["media.class"] = "Audio/Sink"
++  properties["factory.name"] = "support.null-audio-sink"
++  properties["node.virtual"] = "true"
++  properties["monitor.channel-volumes"] = "true"
++
++  properties["wireplumber.is-fallback"] = "true"
++  properties["priority.session"] = 500
++
++  fallback_node = LocalNode("adapter", properties)
++  fallback_node:activate(Feature.Proxy.BOUND)
++end
++
++function checkSinks()
++  local sink_ids_items = 0
++  for _ in pairs(sink_ids) do sink_ids_items = sink_ids_items + 1 end
++
++  if sink_ids_items > 0 then
++    if fallback_node then
++      Log.info("Remove fallback sink")
++      fallback_node = nil
++    end
++  elseif not fallback_node then
++    createFallbackSink()
++  end
++end
++
++function checkSinksAfterTimeout()
++  if timeout_source then
++    timeout_source:destroy()
++  end
++  timeout_source = Core.timeout_add(1000, function ()
++    checkSinks()
++    timeout_source = nil
++  end)
++end
++
++node_om:connect("object-added", function (_, node)
++  Log.debug("object added: " .. node.properties["object.id"] .. " " ..
++      tostring(node.properties["node.name"]))
++
++  sink_ids[node.properties["object.id"]] = node.properties["node.name"]
++
++  checkSinksAfterTimeout()
++end)
++
++node_om:connect("object-removed", function (_, node)
++  Log.debug("object removed: " .. node.properties["object.id"] .. " " ..
++      tostring(node.properties["node.name"]))
++
++  sink_ids[node.properties["object.id"]] = nil
++  checkSinksAfterTimeout()
++end)
++
++node_om:activate()
++
++checkSinksAfterTimeout()
+-- 
+2.25.1
+

debian/patches/apertis-0001-scripts-Automatically-load-fallback-sink.patch

+From c0659653b6b04a5aa2d00a04d153641a7f669c83 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Danis?= <frederic.danis@collabora.com>
+Date: Tue, 5 Apr 2022 09:38:06 +0200
+Subject: [PATCH] scripts: Automatically load fallback sink
+Content-Type: text/plain; charset="utf-8"
+Content-Transfer-Encoding: 8bit
+
+---
+ src/config/main.lua.d/90-enable-all.lua | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/src/config/main.lua.d/90-enable-all.lua b/src/config/main.lua.d/90-enable-all.lua
+index d518805..86777e4 100644
+--- a/src/config/main.lua.d/90-enable-all.lua
++++ b/src/config/main.lua.d/90-enable-all.lua
+@@ -20,3 +20,6 @@ load_script("intended-roles.lua")
+ 
+ -- Automatically suspends idle nodes after 3 seconds
+ load_script("suspend-node.lua")
++
++-- Automatically create fallback sink node
++load_script("fallback-sink.lua")
+-- 
+2.25.1
+

debian/patches/series

+0001-scripts-Add-script-to-create-fallback-sink.patch
+apertis-0001-scripts-Automatically-load-fallback-sink.patch