dbus: add -audio dbus nsamples option

Allow to set the number of audio samples per read/write to dbus.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

audio/dbusaudio.c

@@ -43,9 +43,10 @@
 
 #define DBUS_DISPLAY1_AUDIO_PATH DBUS_DISPLAY1_ROOT "/Audio"
 
-#define DBUS_AUDIO_NSAMPLES 1024 /* could be configured? */
+#define DBUS_DEFAULT_AUDIO_NSAMPLES 480
 
 typedef struct DBusAudio {
+    Audiodev *dev;
     GDBusObjectManagerServer *server;
     bool p2p;
     GDBusObjectSkeleton *audio;
@@ -151,6 +152,18 @@ dbus_init_out_listener(QemuDBusDisplay1AudioOutListener *listener,
         G_DBUS_CALL_FLAGS_NONE, -1, NULL, NULL, NULL);
 }
 
+static guint
+dbus_audio_get_nsamples(DBusAudio *da)
+{
+    AudiodevDBusOptions *opts = &da->dev->u.dbus;
+
+    if (opts->has_nsamples && opts->nsamples) {
+        return opts->nsamples;
+    } else {
+        return DBUS_DEFAULT_AUDIO_NSAMPLES;
+    }
+}
+
 static int
 dbus_init_out(HWVoiceOut *hw, struct audsettings *as, void *drv_opaque)
 {
@@ -160,7 +173,7 @@ dbus_init_out(HWVoiceOut *hw, struct audsettings *as, void *drv_opaque)
     QemuDBusDisplay1AudioOutListener *listener = NULL;
 
     audio_pcm_init_info(&hw->info, as);
-    hw->samples = DBUS_AUDIO_NSAMPLES;
+    hw->samples = dbus_audio_get_nsamples(da);
     audio_rate_start(&vo->rate);
 
     g_hash_table_iter_init(&iter, da->out_listeners);
@@ -274,7 +287,7 @@ dbus_init_in(HWVoiceIn *hw, struct audsettings *as, void *drv_opaque)
     QemuDBusDisplay1AudioInListener *listener = NULL;
 
     audio_pcm_init_info(&hw->info, as);
-    hw->samples = DBUS_AUDIO_NSAMPLES;
+    hw->samples = dbus_audio_get_nsamples(da);
     audio_rate_start(&vo->rate);
 
     g_hash_table_iter_init(&iter, da->in_listeners);
@@ -399,6 +412,7 @@ dbus_audio_init(Audiodev *dev, Error **errp)
 {
     DBusAudio *da = g_new0(DBusAudio, 1);
 
+    da->dev = dev;
     da->out_listeners = g_hash_table_new_full(g_str_hash, g_str_equal,
                                                 g_free, g_object_unref);
     da->in_listeners = g_hash_table_new_full(g_str_hash, g_str_equal,
@@ -652,6 +666,7 @@ dbus_audio_set_server(AudioState *s, GDBusObjectManagerServer *server, bool p2p)
                      "swapped-signal::handle-register-out-listener",
                      dbus_audio_register_out_listener, s,
                      NULL);
+    qemu_dbus_display1_audio_set_nsamples(da->iface, dbus_audio_get_nsamples(da));
 
     g_dbus_object_skeleton_add_interface(G_DBUS_OBJECT_SKELETON(da->audio),
                                          G_DBUS_INTERFACE_SKELETON(da->iface));

qapi/audio.json

@@ -65,6 +65,26 @@
     '*in':  'AudiodevPerDirectionOptions',
     '*out': 'AudiodevPerDirectionOptions' } }
 
+##
+# @AudiodevDBusOptions:
+#
+# Options of the D-Bus audio backend.
+#
+# @in: options of the capture stream
+#
+# @out: options of the playback stream
+#
+# @nsamples: set the number of samples per read/write calls (default to 480,
+# 10ms at 48kHz).
+#
+# Since: 10.0
+##
+{ 'struct': 'AudiodevDBusOptions',
+  'data': {
+    '*in':  'AudiodevPerDirectionOptions',
+    '*out': 'AudiodevPerDirectionOptions',
+    '*nsamples': 'uint32'} }
+
 ##
 # @AudiodevAlsaPerDirectionOptions:
 #
@@ -490,7 +510,7 @@
                    'if': 'CONFIG_AUDIO_ALSA' },
     'coreaudio': { 'type': 'AudiodevCoreaudioOptions',
                    'if': 'CONFIG_AUDIO_COREAUDIO' },
-    'dbus':      { 'type': 'AudiodevGenericOptions',
+    'dbus':      { 'type': 'AudiodevDBusOptions',
                    'if': 'CONFIG_DBUS_DISPLAY' },
     'dsound':    { 'type': 'AudiodevDsoundOptions',
                    'if': 'CONFIG_AUDIO_DSOUND' },

ui/dbus-display1.xml

@@ -773,6 +773,18 @@
       <?endif?>
     </method>
 
+    <!--
+        NSamples:
+
+        The number of samples per read/write frames. (for example the default is
+        480, or 10ms at 48kHz)
+
+        (earlier version of the display interface do not provide this property)
+    -->
+    <property name="NSamples" type="u" access="read">
+      <annotation name="org.freedesktop.DBus.Property.EmitsChangedSignal" value="const"/>
+    </property>
+
     <!--
         Interfaces: