Increase alsa headroom when using pipewire

Pipewire sets the period_size very low by default, which causes
instability with the drivers locking up. Increase the headroom to work
around this. Pulseaudio sets it higher by default so it is not needed
there. Also re-word the status print for avs_dmic.

conf/common/51-increase-headroom.lua

@@ -0,0 +1,12 @@
+rule = {
+    matches = {
+      {
+        { "node.name", "matches", "alsa_output.*" },
+      },
+    },
+    apply_properties = {
+      ["api.alsa.headroom"] = 4096,
+    },
+}
+
+table.insert(alsa_monitor.rules,rule)

setup-audio

@@ -70,7 +70,7 @@ def avs_audio(board, username):
 
     # Install wireplumber config for dmic if wireplumber is installed on the system
     if path_exists("/usr/bin/wireplumber"):
-        print_status("Installing wireplumber config (fixes internal mic)")
+        print_status("Forcing avs_dmic to use S16LE format")
         mkdir("/etc/wireplumber/main.lua.d/", create_parents=True)
         cpfile("conf/avs/51-avs-dmic.lua", "/etc/wireplumber/main.lua.d/51-avs-dmic.lua")
 
@@ -290,4 +290,11 @@ if __name__ == "__main__":
         print_error(f"Unknown/Unsupported chromebook model: {device_board}")
         exit(1)
 
+    # Install wireplumber config to increase headroom
+    # fixes instability and crashes on various devices
+    if path_exists("/usr/bin/wireplumber"):
+      print_status("Increasing alsa headroom (fixes instability)")
+      mkdir("/etc/wireplumber/main.lua.d/", create_parents=True)
+      cpfile("conf/common/51-increase-headroom.lua", "/etc/wireplumber/main.lua.d/51-increase-headroom.lua")
+
     print_header("Audio installed successfully! Reboot to finish setup.")