state-routes.lua: Add new 'bluetooth.keep-volume-on-profile-changed' setting

If enabled, this setting will use the same volume levels as the previous
profile. This is useful on some bluetooth devices if the bluetooth profile
audioswitch is enabled.

po/conf.pot

@@ -13,6 +13,16 @@ msgstr ""
 msgid "Auto-switch to headset profile"
 msgstr ""
 
+#. /wireplumber.settings.schema/bluetooth.keep-volume-on-profile-changed/description
+#: wireplumber.conf
+msgid "Keep same volume levels between Bluetooth profile changes"
+msgstr ""
+
+#. /wireplumber.settings.schema/bluetooth.keep-volume-on-profile-changed/name
+#: wireplumber.conf
+msgid "Keep volume"
+msgstr ""
+
 #. /wireplumber.settings.schema/bluetooth.use-persistent-storage/description
 #: wireplumber.conf
 msgid "Remember and restore Bluetooth headset mode status"

src/config/wireplumber.conf

@@ -847,6 +847,12 @@ wireplumber.settings.schema = {
     type = "bool"
     default = true
   }
+  bluetooth.keep-volume-on-profile-changed = {
+    name = "Keep volume"
+    description = "Keep same volume levels between Bluetooth profile changes"
+    type = "bool"
+    default = false
+  }
 
   ## Device
   device.restore-profile = {

src/scripts/device/state-routes.lua

@@ -21,6 +21,15 @@ log = Log.open_topic ("s-device")
 state = nil
 state_table = nil
 
+-- utilities
+function fillCycle (dest, src)
+  local size = #dest
+  local srcSize = #src
+  for i = 1, size do
+    dest[i] = src[((i - 1) % srcSize) + 1]
+  end
+end
+
 -- hook to restore routes selection for a newly selected profile
 find_stored_routes_hook = SimpleEventHook {
   name = "device/find-stored-routes",
@@ -128,6 +137,24 @@ apply_route_props_hook = SimpleEventHook {
 
       -- convert arrays to Json
       if props.channelVolumes then
+
+        -- fill the channel volumes with the ones from the previous profile if
+        -- this is a BT device and the setting is enabled
+        if device.properties["device.api"] == "bluez5" and
+            Settings.get_boolean ("bluetooth.keep-volume-on-profile-changed") then
+          local prev_profile = dev_info.route_param_prev_profile
+          local route_dir = route_info.direction
+          if dev_info.route_param_profile_changed and
+              dev_info.route_param_channel_volumes[device.id] ~= nil and
+              dev_info.route_param_channel_volumes[device.id][prev_profile] ~= nil then
+            local vols = dev_info.route_param_channel_volumes[device.id][prev_profile][route_dir]
+            if vols ~= nil then
+              log:info (device, "using previous profile channel volumes on route " .. route_info.name)
+              fillCycle (props.channelVolumes, vols)
+            end
+          end
+        end
+
         props.channelVolumes = Json.Array (props.channelVolumes)
       end
       if props.channelMap then
@@ -169,6 +196,7 @@ store_or_restore_routes_hook = AsyncEventHook {
         device:enum_params ("EnumRoute", function (enum_route_it, e)
           local selected_routes = {}
           local push_select_routes = false
+          local profile = nil
 
           -- check for error
           if e then
@@ -189,6 +217,18 @@ store_or_restore_routes_hook = AsyncEventHook {
             return
           end
 
+          -- Update current and previous profiles, and check if they changed
+          for p in device:iterate_params ("Profile") do
+            profile = cutils.parseParam (p, "Profile")
+            if dev_info.route_param_curr_profile ~= profile.index then
+              dev_info.route_param_prev_profile = dev_info.route_param_curr_profile
+              dev_info.route_param_curr_profile = profile.index
+              dev_info.route_param_profile_changed = true
+            else
+              dev_info.route_param_profile_changed = false
+            end
+          end
+
           local new_route_infos = {}
 
           -- look at all the routes and update/reset cached information
@@ -227,6 +267,18 @@ store_or_restore_routes_hook = AsyncEventHook {
               goto skip_route
             end
 
+            -- cache the device input and output route channel volumes for current profile
+            local curr_profile = dev_info.route_param_curr_profile
+            local route_dir = route.direction
+            if dev_info.route_param_channel_volumes [device.id] == nil then
+              dev_info.route_param_channel_volumes [device.id] = {}
+            end
+            if dev_info.route_param_channel_volumes [device.id][curr_profile] == nil then
+              dev_info.route_param_channel_volumes [device.id][curr_profile] = {}
+            end
+            dev_info.route_param_channel_volumes [device.id][curr_profile][route_dir] =
+                route.props.properties.channelVolumes
+
             -- get cached route info and at the same time
             -- ensure that the route is also in EnumRoute
             local route_info = devinfo.find_route_info (dev_info, route, false)
@@ -264,10 +316,8 @@ store_or_restore_routes_hook = AsyncEventHook {
           end
 
           -- save selected routes for the active profile
-          for p in device:iterate_params ("Profile") do
-            local profile = cutils.parseParam (p, "Profile")
-            saveProfileRoutes (dev_info, profile.name)
-          end
+          assert (profile)
+          saveProfileRoutes (dev_info, profile.name)
 
           -- push a select-routes event to re-apply the routes with new properties
           if push_select_routes then

src/scripts/lib/device-info-cache.lua

@@ -44,6 +44,10 @@ function module.get_device_info (self, device)
       name = device_name,
       active_profile = -1,
       route_infos = {},
+      route_param_curr_profile = -1,
+      route_param_prev_profile = -1,
+      route_param_profile_changed = false,
+      route_param_channel_volumes = {}
     }
     self.dev_infos [device_id] = dev_info
   end