linking: explicitly mark targets that should be managed by the role-based policy

The previous assumption that any target with "device.intended-roles"
should be managed by the role-based policy is wrong, as for example
Bluetooth SCO nodes always have "device.intended-roles = Communication"
and some ALSA devices managed by ACP also do. This is meant to be used
as a hint for the desktop policy (it's been there in PulseAudio as well)
and does not necessarily mean that a role-priority-based policy should
be applied on all links to those devices.

Instead, use a new property to explicitly mark all the targets that
are meant to be managed by the role-based policy and respect that in
all places where we check for a potential role-based policy link.

Fixes: #682

src/config/wireplumber.conf.d.examples/media-role-nodes.conf

@@ -36,6 +36,11 @@ wireplumber.components.rules = [
       merge = {
         arguments = {
           capture.props = {
+            # Explicitly mark all these sinks as valid role-based policy
+            # targets, meaning that any links between streams and these sinks
+            # will be managed by the role-based policy
+            policy.role-based.target = true
+
             audio.position = [ FL, FR ]
             media.class = Audio/Sink
           }

src/scripts/lib/linking-utils.lua

@@ -63,7 +63,7 @@ function lutils.clearPriorityMediaRoleLink (link)
   for l in cutils.get_object_manager ("session-item"):iterate {
     type = "SiLink",
     Constraint { "item.factory.name", "=", "si-standard-link", type = "pw-global" },
-    Constraint { "is.media.role.link", "=", true },
+    Constraint { "is.role.policy.link", "=", true },
     Constraint { "target.media.class", "=", lmc },
   } do
     local props = l.properties
@@ -122,6 +122,17 @@ function setPriorityMediaRoleLink (lmc, link)
   end
 end
 
+function lutils.is_role_policy_target (si_props, target_props)
+  -- role-based policy links are those that link to targets with
+  -- policy.role-based.target = true, unless the stream is a monitor
+  -- (usually pavucontrol) or the stream is linking to the monitor ports
+  -- of a sink (both are "input")
+  return Core.test_feature ("hooks.linking.role-based.rescan")
+      and cutils.parseBool (target_props["policy.role-based.target"])
+      and not cutils.parseBool (si_props ["stream.monitor"])
+      and si_props["item.node.direction"] ~= target_props["item.node.direction"]
+end
+
 function lutils.unwrap_select_target_event (self, event)
   local source = event:get_source ()
   local si = event:get_subject ()

src/scripts/linking/get-filter-from-target.lua

@@ -28,8 +28,8 @@ SimpleEventHook {
     local source, om, si, si_props, si_flags, target =
         lutils:unwrap_select_target_event (event)
 
-    -- bypass the hook if the target was not found or if the target is media role node
-    if target == nil or target.properties["device.intended-roles"] then
+    -- bypass the hook if the target was not found or if it is a role-based policy target
+    if target == nil or lutils.is_role_policy_target (si_props, target.properties) then
       return
     end
 

src/scripts/linking/link-target.lua

@@ -63,13 +63,7 @@ AsyncEventHook {
           out_item = target
         end
 
-        -- role links are those that link to targets with intended-roles
-        -- unless the stream is a monitor (usually pavucontrol) or the stream
-        -- is linking to the monitor ports of a sink (both are "input")
-        local is_media_role_link = Core.test_feature ("hooks.linking.role-based.rescan")
-            and target_props["device.intended-roles"] ~= nil
-            and not cutils.parseBool (si_props ["stream.monitor"])
-            and si_props["item.node.direction"] ~= target_props["item.node.direction"]
+        local is_role_policy_link = lutils.is_role_policy_target (si_props, target_props)
 
         log:info (si,
           string.format ("link %s <-> %s passthrough:%s, exclusive:%s, media role link:%s",
@@ -77,7 +71,7 @@ AsyncEventHook {
             tostring (target_props ["node.name"]),
             tostring (passthrough),
             tostring (exclusive),
-            tostring (is_media_role_link)))
+            tostring (is_role_policy_link)))
 
         -- create and configure link
         si_link = SessionItem ("si-standard-link")
@@ -93,7 +87,7 @@ AsyncEventHook {
           ["policy.role-based.priority"] = target_props["policy.role-based.priority"],
           ["policy.role-based.action.same-priority"] = target_props["policy.role-based.action.same-priority"],
           ["policy.role-based.action.lower-priority"] = target_props["policy.role-based.action.lower-priority"],
-          ["is.media.role.link"] = is_media_role_link,
+          ["is.role.policy.link"] = is_role_policy_link,
           ["main.item.id"] = si.id,
           ["target.item.id"] = target.id,
         } then
@@ -129,9 +123,9 @@ AsyncEventHook {
         log:debug (si_link, "registered link between "
             .. tostring (si) .. " and " .. tostring (target))
 
-        -- only activate non media role links because their activation is
+        -- only activate non role-based policy links because their activation is
         -- handled by rescan-media-role-links.lua
-        if not is_media_role_link then
+        if not is_role_policy_link then
           si_link:activate (Feature.SessionItem.ACTIVE, function (l, e)
             if e then
               transition:return_error (tostring (l) .. " link failed: "

src/scripts/linking/rescan-media-role-links.lua

@@ -85,7 +85,7 @@ AsyncEventHook {
       -- on media client link added and removed
       Constraint { "event.type", "c", "session-item-added", "session-item-removed" },
       Constraint { "event.session-item.interface", "=", "link" },
-      Constraint { "is.media.role.link", "=", true },
+      Constraint { "is.role.policy.link", "=", true },
     },
     EventInterest {
       -- on default metadata suspend.playback changed
@@ -140,7 +140,7 @@ AsyncEventHook {
 
         for link in om:iterate {
           type = "SiLink",
-          Constraint { "is.media.role.link", "=", true },
+          Constraint { "is.role.policy.link", "=", true },
           Constraint { "target.media.class", "=", mc },
         } do
           -- deactivate all links if suspend playback metadata is present

src/scripts/linking/rescan.lua

@@ -82,7 +82,7 @@ function unhandleLinkable (si, om)
         out_flags.peer_id = nil
       end
 
-      if cutils.parseBool (silink.properties["is.media.role.link"]) then
+      if cutils.parseBool (silink.properties["is.role.policy.link"]) then
         lutils.clearPriorityMediaRoleLink(silink)
       end