More hacking

Add connection message for PORT_COMMAND
Add rtkit support to ask for realtime priority
work on stream states and improve negotiation
Rework of port linking works, keep separate state for realtime threads
and use message passing to update the state.
Don't try to link nodes that are removed.
Open the device in the ALSA monitor to detect source or sink
Implement send_command as async methods on the plugins, use async
replies to sync start and stop.
Work on alsa sink.
Implement async PAUSE/START on v4l2 src. move the STREAMON/OFF calls to
the mainloop because they have high latency, add the poll descriptors
from the data loop.

32 files changed, 1317 insertions, 527 deletions

diff --git a/pinos/client/connection.c b/pinos/client/connection.c
index 3411cf6b..27aed319 100644
--- a/pinos/client/connection.c
+++ b/pinos/client/connection.c
@@ -151,6 +151,15 @@ connection_parse_node_command (PinosConnection *conn, PinosControlCmdNodeCommand
     cmd->command = SPA_MEMBER (p, SPA_PTR_TO_INT (cmd->command), SpaNodeCommand);
 }
 
+static void
+connection_parse_port_command (PinosConnection *conn, PinosControlCmdPortCommand *cmd)
+{
+  void *p = conn->in.data;
+  memcpy (cmd, p, sizeof (PinosControlCmdPortCommand));
+  if (cmd->command)
+    cmd->command = SPA_MEMBER (p, SPA_PTR_TO_INT (cmd->command), SpaNodeCommand);
+}
+
 static void *
 connection_ensure_size (PinosConnection *conn, ConnectionBuffer *buf, size_t size)
 {
@@ -363,6 +372,27 @@ connection_add_node_command (PinosConnection *conn, PinosControlCmdNodeCommand *
   memcpy (p, cm->command, cm->command->size);
 }
 
+static void
+connection_add_port_command (PinosConnection *conn, PinosControlCmdPortCommand *cm)
+{
+  size_t len;
+  void *p;
+  PinosControlCmdPortCommand *d;
+
+  /* calculate length */
+  len = sizeof (PinosControlCmdPortCommand);
+  len += cm->command->size;
+
+  p = connection_add_cmd (conn, PINOS_CONTROL_CMD_PORT_COMMAND, len);
+  memcpy (p, cm, sizeof (PinosControlCmdPortCommand));
+  d = p;
+
+  p = SPA_MEMBER (d, sizeof (PinosControlCmdPortCommand), void);
+  d->command = SPA_INT_TO_PTR (SPA_PTRDIFF (p, d));
+
+  memcpy (p, cm->command, cm->command->size);
+}
+
 static gboolean
 refill_buffer (PinosConnection *conn, ConnectionBuffer *buf)
 {
@@ -595,6 +625,10 @@ pinos_connection_parse_cmd (PinosConnection *conn,
       connection_parse_node_command (conn, command);
       break;
 
+    case PINOS_CONTROL_CMD_PORT_COMMAND:
+      connection_parse_port_command (conn, command);
+      break;
+
     case PINOS_CONTROL_CMD_INVALID:
       return FALSE;
   }
@@ -742,6 +776,10 @@ pinos_connection_add_cmd (PinosConnection *conn,
       connection_add_node_command (conn, command);
       break;
 
+    case PINOS_CONTROL_CMD_PORT_COMMAND:
+      connection_add_port_command (conn, command);
+      break;
+
     case PINOS_CONTROL_CMD_INVALID:
       return FALSE;
   }
diff --git a/pinos/client/connection.h b/pinos/client/connection.h
index 165e58d9..6517ace8 100644
--- a/pinos/client/connection.h
+++ b/pinos/client/connection.h
@@ -49,6 +49,7 @@ typedef enum {
   PINOS_CONTROL_CMD_SET_PROPERTY             = 35,
 
   PINOS_CONTROL_CMD_NODE_COMMAND             = 36,
+  PINOS_CONTROL_CMD_PORT_COMMAND             = 37,
 
   /* both */
   PINOS_CONTROL_CMD_ADD_MEM                  = 64,
@@ -132,6 +133,12 @@ typedef struct {
   SpaNodeCommand *command;
 } PinosControlCmdNodeCommand;
 
+/* PINOS_CONTROL_CMD_PORT_COMMAND */
+typedef struct {
+  uint32_t        port_id;
+  SpaNodeCommand *command;
+} PinosControlCmdPortCommand;
+
 /* PINOS_CONTROL_CMD_ADD_MEM */
 typedef struct {
   SpaDirection direction;
diff --git a/pinos/client/introspect.h b/pinos/client/introspect.h
index bad88de0..d4187383 100644
--- a/pinos/client/introspect.h
+++ b/pinos/client/introspect.h
@@ -23,6 +23,8 @@
 #include <gio/gio.h>
 #include <glib-object.h>
 
+#include <spa/include/spa/defs.h>
+
 G_BEGIN_DECLS
 
 /**
@@ -59,9 +61,9 @@ const gchar * pinos_node_state_as_string (PinosNodeState state);
  * The direction of a port
  */
 typedef enum {
-  PINOS_DIRECTION_INVALID = 0,
-  PINOS_DIRECTION_INPUT = 1,
-  PINOS_DIRECTION_OUTPUT = 2
+  PINOS_DIRECTION_INVALID = SPA_DIRECTION_INVALID,
+  PINOS_DIRECTION_INPUT = SPA_DIRECTION_INPUT,
+  PINOS_DIRECTION_OUTPUT = SPA_DIRECTION_OUTPUT
 } PinosDirection;
 
 const gchar * pinos_direction_as_string (PinosDirection direction);
diff --git a/pinos/client/meson.build b/pinos/client/meson.build
index dc12c962..d6ed7a23 100644
--- a/pinos/client/meson.build
+++ b/pinos/client/meson.build
@@ -4,8 +4,9 @@ pinos_headers = [
   'introspect.h',
   'pinos.h',
   'properties.h',
-  'stream.h',
   'ringbuffer.h',
+  'rtkit.h',
+  'stream.h',
   'subscribe.h',
   'thread-mainloop.h',
 ]
@@ -20,6 +21,7 @@ pinos_sources = [
   'stream.c',
   'pinos.c',
   'ringbuffer.c',
+  'rtkit.c',
   'subscribe.c',
   'thread-mainloop.c',
   gdbus_target,
diff --git a/pinos/client/rtkit.c b/pinos/client/rtkit.c
new file mode 100644
index 00000000..cb2f51a2
--- /dev/null
+++ b/pinos/client/rtkit.c
@@ -0,0 +1,104 @@
+/* Pinos
+ * Copyright (C) 2015 Wim Taymans <wim.taymans@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include <sys/syscall.h>
+
+#include "rtkit.h"
+
+static pid_t _gettid(void) {
+  return (pid_t) syscall(SYS_gettid);
+}
+
+gboolean
+pinos_rtkit_make_realtime (GDBusConnection     *system_bus,
+                           pid_t                thread,
+                           gint                 priority,
+                           GError             **error)
+{
+  GVariant *v;
+
+  if (thread == 0)
+    thread = _gettid();
+
+  v = g_dbus_connection_call_sync (system_bus,
+                                   RTKIT_SERVICE_NAME,
+                                   RTKIT_OBJECT_PATH,
+                                   "org.freedesktop.RealtimeKit1",
+                                   "MakeThreadRealtime",
+                                   g_variant_new ("(tu)",
+                                     (guint64) thread,
+                                     (guint32) priority),
+                                   NULL,
+                                   G_DBUS_CALL_FLAGS_NONE,
+                                   -1,
+                                   NULL,
+                                   error);
+  if (v)
+    g_variant_unref (v);
+
+  return v != NULL;
+}
+
+gboolean
+pinos_rtkit_make_high_priority (GDBusConnection     *system_bus,
+                                pid_t                thread,
+                                gint                 nice_level,
+                                GError             **error)
+{
+  GVariant *v;
+
+  if (thread == 0)
+    thread = _gettid();
+
+  v = g_dbus_connection_call_sync (system_bus,
+                                   RTKIT_SERVICE_NAME,
+                                   RTKIT_OBJECT_PATH,
+                                   "org.freedesktop.RealtimeKit1",
+                                   "MakeThreadHighPriority",
+                                   g_variant_new ("(tu)",
+                                     (guint64) thread,
+                                     (guint32) nice_level),
+                                   NULL,
+                                   G_DBUS_CALL_FLAGS_NONE,
+                                   -1,
+                                   NULL,
+                                   error);
+  if (v)
+    g_variant_unref (v);
+
+  return v != NULL;
+}
+
+int pinos_rtkit_get_max_realtime_priority (GDBusConnection *system_bus)
+{
+  return 0;
+}
+
+int pinos_rtkit_get_min_nice_level (GDBusConnection *system_bus, int* min_nice_level)
+{
+  return 0;
+}
+
+/* Return the maximum value of RLIMIT_RTTIME to set before attempting a
+ * realtime request. A negative value is an errno style error code.
+ */
+long long rtkit_get_rttime_usec_max (GDBusConnection *system_bus)
+{
+  return 0;
+}
diff --git a/pinos/client/rtkit.h b/pinos/client/rtkit.h
new file mode 100644
index 00000000..87b3da92
--- /dev/null
+++ b/pinos/client/rtkit.h
@@ -0,0 +1,68 @@
+/* Pinos
+ * Copyright (C) 2015 Wim Taymans <wim.taymans@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __PINOS_RTKIT_H__
+#define __PINOS_RTKIT_H__
+
+#include <gio/gio.h>
+#include <glib-object.h>
+
+G_BEGIN_DECLS
+
+#define RTKIT_SERVICE_NAME "org.freedesktop.RealtimeKit1"
+#define RTKIT_OBJECT_PATH "/org/freedesktop/RealtimeKit1"
+
+/* This is mostly equivalent to sched_setparam(thread, SCHED_RR, {
+ * .sched_priority = priority }). 'thread' needs to be a kernel thread
+ * id as returned by gettid(), not a pthread_t! If 'thread' is 0 the
+ * current thread is used.
+ */
+gboolean        pinos_rtkit_make_realtime        (GDBusConnection     *system_bus,
+                                                  pid_t                thread,
+                                                  gint                 priority,
+                                                  GError             **error);
+
+
+/* This is mostly equivalent to setpriority(PRIO_PROCESS, thread,
+ * nice_level). 'thread' needs to be a kernel thread id as returned by
+ * gettid(), not a pthread_t! If 'thread' is 0 the current thread is
+ * used. */
+gboolean        pinos_rtkit_make_high_priority          (GDBusConnection     *system_bus,
+                                                         pid_t                thread,
+                                                         gint                 nice_level,
+                                                         GError             **error);
+
+/* Return the maximum value of realtime priority available. Realtime requests
+ * above this value will fail. A negative value is an errno style error code.
+ */
+int pinos_rtkit_get_max_realtime_priority (GDBusConnection *system_bus);
+
+/* Retreive the minimum value of nice level available. High prio requests
+ * below this value will fail. The returned value is a negative errno
+ * style error code, or 0 on success.*/
+int pinos_rtkit_get_min_nice_level (GDBusConnection *system_bus, int* min_nice_level);
+
+/* Return the maximum value of RLIMIT_RTTIME to set before attempting a
+ * realtime request. A negative value is an errno style error code.
+ */
+long long rtkit_get_rttime_usec_max (GDBusConnection *system_bus);
+
+G_END_DECLS
+
+#endif /* __PINOS_RTKIT_H__ */
diff --git a/pinos/client/stream.c b/pinos/client/stream.c
index 3b6f5675..57cc7429 100644
--- a/pinos/client/stream.c
+++ b/pinos/client/stream.c
@@ -874,7 +874,7 @@ handle_node_command (PinosStream    *stream,
       break;
     case SPA_NODE_COMMAND_PAUSE:
     {
-      g_debug ("stream %p: pause", stream);
+      g_debug ("stream %p: pause %d", stream, seq);
 
       add_state_change (stream, SPA_NODE_STATE_PAUSED);
       add_async_complete (stream, seq, SPA_RESULT_OK);
@@ -882,12 +882,12 @@ handle_node_command (PinosStream    *stream,
       if (!pinos_connection_flush (priv->conn))
         g_warning ("stream %p: error writing connection", stream);
 
-      stream_set_state (stream, PINOS_STREAM_STATE_READY, NULL);
+      stream_set_state (stream, PINOS_STREAM_STATE_PAUSED, NULL);
       break;
     }
     case SPA_NODE_COMMAND_START:
     {
-      g_debug ("stream %p: start", stream);
+      g_debug ("stream %p: start %d", stream, seq);
       add_state_change (stream, SPA_NODE_STATE_STREAMING);
       add_async_complete (stream, seq, SPA_RESULT_OK);
 
@@ -911,7 +911,6 @@ handle_node_command (PinosStream    *stream,
         g_warning ("stream %p: error writing connection", stream);
       break;
     }
-
     case SPA_NODE_COMMAND_CLOCK_UPDATE:
     {
       SpaNodeCommandClockUpdate *cu = (SpaNodeCommandClockUpdate *) command;
@@ -945,7 +944,7 @@ parse_connection (PinosStream *stream)
       case PINOS_CONTROL_CMD_PORT_STATUS_CHANGE:
       case PINOS_CONTROL_CMD_NODE_STATE_CHANGE:
       case PINOS_CONTROL_CMD_PROCESS_BUFFER:
-        g_warning ("got unexpected connection %d", cmd);
+        g_warning ("got unexpected command %d", cmd);
         break;
 
       case PINOS_CONTROL_CMD_ADD_PORT:
@@ -968,6 +967,7 @@ parse_connection (PinosStream *stream)
 
         priv->pending_seq = p.seq;
         g_object_notify (G_OBJECT (stream), "format");
+        stream_set_state (stream, PINOS_STREAM_STATE_READY, NULL);
         break;
       }
       case PINOS_CONTROL_CMD_SET_PROPERTY:
@@ -1114,6 +1114,11 @@ parse_connection (PinosStream *stream)
 
         if (!pinos_connection_flush (conn))
           g_warning ("stream %p: error writing connection", stream);
+
+        if (p.n_buffers)
+          stream_set_state (stream, PINOS_STREAM_STATE_PAUSED, NULL);
+        else
+          stream_set_state (stream, PINOS_STREAM_STATE_READY, NULL);
         break;
       }
       case PINOS_CONTROL_CMD_NODE_EVENT:
@@ -1136,7 +1141,15 @@ parse_connection (PinosStream *stream)
         handle_node_command (stream, p.seq, p.command);
         break;
       }
+      case PINOS_CONTROL_CMD_PORT_COMMAND:
+      {
+        PinosControlCmdPortCommand p;
 
+        if (!pinos_connection_parse_cmd (conn, &p))
+          break;
+
+        break;
+      }
       case PINOS_CONTROL_CMD_INVALID:
         g_warning ("unhandled command %d", cmd);
         break;
@@ -1167,7 +1180,7 @@ parse_rtconnection (PinosStream *stream)
       case PINOS_CONTROL_CMD_ADD_MEM:
       case PINOS_CONTROL_CMD_USE_BUFFERS:
       case PINOS_CONTROL_CMD_NODE_COMMAND:
-        g_warning ("got unexpected connection %d", cmd);
+        g_warning ("got unexpected command %d", cmd);
         break;
 
       case PINOS_CONTROL_CMD_PROCESS_BUFFER:
@@ -1202,6 +1215,10 @@ parse_rtconnection (PinosStream *stream)
         handle_rtnode_event (stream, p.event);
         break;
       }
+      case PINOS_CONTROL_CMD_PORT_COMMAND:
+      {
+        break;
+      }
     }
   }
 
@@ -1344,7 +1361,7 @@ on_node_proxy (GObject      *source_object,
 
   do_node_init (stream);
 
-  stream_set_state (stream, PINOS_STREAM_STATE_READY, NULL);
+  stream_set_state (stream, PINOS_STREAM_STATE_CONFIGURE, NULL);
   g_object_unref (stream);
 
   return;
@@ -1664,9 +1681,7 @@ pinos_stream_start (PinosStream     *stream)
   g_return_val_if_fail (PINOS_IS_STREAM (stream), FALSE);
 
   priv = stream->priv;
-  g_return_val_if_fail (priv->state == PINOS_STREAM_STATE_READY, FALSE);
-
-  stream_set_state (stream, PINOS_STREAM_STATE_STARTING, NULL);
+  //g_return_val_if_fail (priv->state == PINOS_STREAM_STATE_PAUSED, FALSE);
 
   g_main_context_invoke (priv->context->priv->context,
                          (GSourceFunc) do_start,
@@ -1709,8 +1724,8 @@ pinos_stream_stop (PinosStream *stream)
 
 static void
 on_node_removed (GObject      *source_object,
-                          GAsyncResult *res,
-                          gpointer      user_data)
+                 GAsyncResult *res,
+                 gpointer      user_data)
 {
   PinosStream *stream = user_data;
   PinosStreamPrivate *priv = stream->priv;
diff --git a/pinos/client/stream.h b/pinos/client/stream.h
index 1ac07ff2..6237dc78 100644
--- a/pinos/client/stream.h
+++ b/pinos/client/stream.h
@@ -47,9 +47,10 @@ typedef enum {
   PINOS_STREAM_STATE_ERROR       = -1,
   PINOS_STREAM_STATE_UNCONNECTED = 0,
   PINOS_STREAM_STATE_CONNECTING  = 1,
-  PINOS_STREAM_STATE_READY       = 2,
-  PINOS_STREAM_STATE_STARTING    = 3,
-  PINOS_STREAM_STATE_STREAMING   = 4
+  PINOS_STREAM_STATE_CONFIGURE   = 2,
+  PINOS_STREAM_STATE_READY       = 3,
+  PINOS_STREAM_STATE_PAUSED      = 4,
+  PINOS_STREAM_STATE_STREAMING   = 5
 } PinosStreamState;
 
 const gchar * pinos_stream_state_as_string (PinosStreamState state);
diff --git a/pinos/gst/gstpinospool.c b/pinos/gst/gstpinospool.c
index 2019bb11..b941e6ec 100644
--- a/pinos/gst/gstpinospool.c
+++ b/pinos/gst/gstpinospool.c
@@ -92,6 +92,7 @@ release_buffer (GstBufferPool * pool, GstBuffer *buffer)
   GST_DEBUG ("release buffer %p", buffer);
   GST_OBJECT_LOCK (pool);
   g_queue_push_tail (&p->available, buffer);
+  g_cond_signal (&p->cond);
   GST_OBJECT_UNLOCK (pool);
 }
 
diff --git a/pinos/gst/gstpinossink.c b/pinos/gst/gstpinossink.c
index 9c819803..224876a2 100644
--- a/pinos/gst/gstpinossink.c
+++ b/pinos/gst/gstpinossink.c
@@ -450,6 +450,7 @@ on_new_buffer (GObject    *gobject,
   buf = g_hash_table_lookup (pinossink->buf_ids, GINT_TO_POINTER (id));
 
   if (buf) {
+    gst_buffer_unref (buf);
     pinos_thread_main_loop_signal (pinossink->loop, FALSE);
   }
 }
@@ -469,9 +470,10 @@ on_stream_notify (GObject    *gobject,
   switch (state) {
     case PINOS_STREAM_STATE_UNCONNECTED:
     case PINOS_STREAM_STATE_CONNECTING:
-    case PINOS_STREAM_STATE_STARTING:
-    case PINOS_STREAM_STATE_STREAMING:
+    case PINOS_STREAM_STATE_CONFIGURE:
     case PINOS_STREAM_STATE_READY:
+    case PINOS_STREAM_STATE_PAUSED:
+    case PINOS_STREAM_STATE_STREAMING:
       break;
     case PINOS_STREAM_STATE_ERROR:
       GST_ELEMENT_ERROR (pinossink, RESOURCE, FAILED,
@@ -487,6 +489,7 @@ on_format_notify (GObject    *gobject,
                   GParamSpec *pspec,
                   gpointer    user_data)
 {
+#if 0
   GstPinosSink *pinossink = user_data;
   GstStructure *config;
   GstCaps *caps;
@@ -514,6 +517,7 @@ on_format_notify (GObject    *gobject,
   param_meta_enable.type = SPA_META_TYPE_HEADER;
 
   pinos_stream_finish_format (pinossink->stream, SPA_RESULT_OK, port_params, 2);
+#endif
 }
 
 static gboolean
@@ -634,10 +638,12 @@ gst_pinos_sink_render (GstBaseSink * bsink, GstBuffer * buffer)
     d->offset = mem->offset;
     d->size = mem->size;
   }
+  gst_buffer_ref (buffer);
 
   if (!(res = pinos_stream_send_buffer (pinossink->stream, data->id)))
     g_warning ("can't send buffer");
 
+
 done:
   pinos_thread_main_loop_unlock (pinossink->loop);
 
diff --git a/pinos/gst/gstpinossrc.c b/pinos/gst/gstpinossrc.c
index 1e6d17c3..e2fa1abc 100644
--- a/pinos/gst/gstpinossrc.c
+++ b/pinos/gst/gstpinossrc.c
@@ -451,38 +451,39 @@ on_new_buffer (GObject    *gobject,
 {
   GstPinosSrc *pinossrc = user_data;
   GstBuffer *buf;
+  ProcessMemData *data;
+  SpaMetaHeader *h;
+  guint i;
 
   GST_LOG_OBJECT (pinossrc, "got new buffer");
   buf = g_hash_table_lookup (pinossrc->buf_ids, GINT_TO_POINTER (id));
+  if (buf == NULL) {
+    g_warning ("unknown buffer %d", id);
+    return;
+  }
 
-  if (buf) {
-    ProcessMemData *data;
-    SpaMetaHeader *h;
-    guint i;
+  data = gst_mini_object_get_qdata (GST_MINI_OBJECT_CAST (buf),
+                                  process_mem_data_quark);
+  h = data->header;
+  if (h) {
+    GST_INFO ("pts %" G_GUINT64_FORMAT ", dts_offset %"G_GUINT64_FORMAT, h->pts, h->dts_offset);
 
-    data = gst_mini_object_get_qdata (GST_MINI_OBJECT_CAST (buf),
-                                    process_mem_data_quark);
-    h = data->header;
-    if (h) {
-      GST_INFO ("pts %" G_GUINT64_FORMAT ", dts_offset %"G_GUINT64_FORMAT, h->pts, h->dts_offset);
-
-      if (GST_CLOCK_TIME_IS_VALID (h->pts)) {
-        GST_BUFFER_PTS (buf) = h->pts;
-        if (GST_BUFFER_PTS (buf) + h->dts_offset > 0)
-          GST_BUFFER_DTS (buf) = GST_BUFFER_PTS (buf) + h->dts_offset;
-      }
-      GST_BUFFER_OFFSET (buf) = h->seq;
-    }
-    for (i = 0; i < data->buf->n_datas; i++) {
-      SpaData *d = &data->buf->datas[i];
-      GstMemory *mem = gst_buffer_peek_memory (buf, i);
-      mem->offset = d->offset;
-      mem->size = d->size;
+    if (GST_CLOCK_TIME_IS_VALID (h->pts)) {
+      GST_BUFFER_PTS (buf) = h->pts;
+      if (GST_BUFFER_PTS (buf) + h->dts_offset > 0)
+        GST_BUFFER_DTS (buf) = GST_BUFFER_PTS (buf) + h->dts_offset;
     }
-    g_queue_push_tail (&pinossrc->queue, buf);
-
-    pinos_thread_main_loop_signal (pinossrc->loop, FALSE);
+    GST_BUFFER_OFFSET (buf) = h->seq;
   }
+  for (i = 0; i < data->buf->n_datas; i++) {
+    SpaData *d = &data->buf->datas[i];
+    GstMemory *mem = gst_buffer_peek_memory (buf, i);
+    mem->offset = d->offset;
+    mem->size = d->size;
+  }
+  g_queue_push_tail (&pinossrc->queue, buf);
+
+  pinos_thread_main_loop_signal (pinossrc->loop, FALSE);
   return;
 }
 
@@ -494,14 +495,15 @@ on_stream_notify (GObject    *gobject,
   GstPinosSrc *pinossrc = user_data;
   PinosStreamState state = pinos_stream_get_state (pinossrc->stream);
 
-  GST_DEBUG ("got stream state %d", state);
+  GST_DEBUG ("got stream state %s", pinos_stream_state_as_string (state));
 
   switch (state) {
     case PINOS_STREAM_STATE_UNCONNECTED:
     case PINOS_STREAM_STATE_CONNECTING:
-    case PINOS_STREAM_STATE_STARTING:
-    case PINOS_STREAM_STATE_STREAMING:
+    case PINOS_STREAM_STATE_CONFIGURE:
     case PINOS_STREAM_STATE_READY:
+    case PINOS_STREAM_STATE_PAUSED:
+    case PINOS_STREAM_STATE_STREAMING:
       break;
     case PINOS_STREAM_STATE_ERROR:
       GST_ELEMENT_ERROR (pinossrc, RESOURCE, FAILED,
@@ -529,6 +531,8 @@ parse_stream_properties (GstPinosSrc *pinossrc, PinosProperties *props)
   pinossrc->max_latency = var ? (GstClockTime) atoi (var) : GST_CLOCK_TIME_NONE;
   GST_OBJECT_UNLOCK (pinossrc);
 
+  GST_DEBUG_OBJECT (pinossrc, "live %d", is_live);
+
   gst_base_src_set_live (GST_BASE_SRC (pinossrc), is_live);
 }
 
@@ -539,10 +543,12 @@ gst_pinos_src_stream_start (GstPinosSrc *pinossrc)
   PinosProperties *props;
 
   pinos_thread_main_loop_lock (pinossrc->loop);
+  GST_DEBUG_OBJECT (pinossrc, "doing stream start");
   res = pinos_stream_start (pinossrc->stream);
   while (TRUE) {
     PinosStreamState state = pinos_stream_get_state (pinossrc->stream);
 
+    GST_DEBUG_OBJECT (pinossrc, "waiting for STREAMING, now %s", pinos_stream_state_as_string (state));
     if (state == PINOS_STREAM_STATE_STREAMING)
       break;
 
@@ -559,6 +565,7 @@ gst_pinos_src_stream_start (GstPinosSrc *pinossrc)
   pinos_properties_free (props);
 
   pinos_thread_main_loop_lock (pinossrc->loop);
+  GST_DEBUG_OBJECT (pinossrc, "signal started");
   pinossrc->started = TRUE;
   pinos_thread_main_loop_signal (pinossrc->loop, FALSE);
   pinos_thread_main_loop_unlock (pinossrc->loop);
@@ -582,6 +589,8 @@ wait_negotiated (GstPinosSrc *this)
   while (TRUE) {
     state = pinos_stream_get_state (this->stream);
 
+    GST_DEBUG_OBJECT (this, "waiting for started signal, state now %s",
+        pinos_stream_state_as_string (state));
     if (state == PINOS_STREAM_STATE_ERROR)
       break;
 
@@ -590,6 +599,7 @@ wait_negotiated (GstPinosSrc *this)
 
     pinos_thread_main_loop_wait (this->loop);
   }
+  GST_DEBUG_OBJECT (this, "got started signal");
   pinos_thread_main_loop_unlock (this->loop);
 
   return state;
@@ -642,6 +652,7 @@ gst_pinos_src_negotiate (GstBaseSrc * basesrc)
     while (TRUE) {
       PinosStreamState state = pinos_stream_get_state (pinossrc->stream);
 
+      GST_DEBUG_OBJECT (basesrc, "waiting for UNCONNECTED, now %s", pinos_stream_state_as_string (state));
       if (state == PINOS_STREAM_STATE_UNCONNECTED)
         break;
 
@@ -665,7 +676,9 @@ gst_pinos_src_negotiate (GstBaseSrc * basesrc)
   while (TRUE) {
     PinosStreamState state = pinos_stream_get_state (pinossrc->stream);
 
-    if (state == PINOS_STREAM_STATE_READY)
+    GST_DEBUG_OBJECT (basesrc, "waiting for PAUSED, now %s", pinos_stream_state_as_string (state));
+    if (state == PINOS_STREAM_STATE_PAUSED ||
+        state == PINOS_STREAM_STATE_STREAMING)
       break;
 
     if (state == PINOS_STREAM_STATE_ERROR)
@@ -726,6 +739,7 @@ on_format_notify (GObject    *gobject,
   g_object_get (gobject, "format", &format, NULL);
 
   caps = gst_caps_from_format (format);
+  GST_DEBUG_OBJECT (pinossrc, "we got format %" GST_PTR_FORMAT, caps);
   res = gst_base_src_set_caps (GST_BASE_SRC (pinossrc), caps);
   gst_caps_unref (caps);
 
@@ -738,8 +752,10 @@ on_format_notify (GObject    *gobject,
     param_meta.param.size = sizeof (param_meta);
     param_meta.type = SPA_META_TYPE_HEADER;
 
+    GST_DEBUG_OBJECT (pinossrc, "doing finish format");
     pinos_stream_finish_format (pinossrc->stream, SPA_RESULT_OK, params, 1);
   } else {
+    GST_WARNING_OBJECT (pinossrc, "finish format with error");
     pinos_stream_finish_format (pinossrc->stream, SPA_RESULT_INVALID_MEDIA_TYPE, NULL, 0);
   }
 }
@@ -948,7 +964,7 @@ on_context_notify (GObject    *gobject,
   GstPinosSrc *pinossrc = user_data;
   PinosContextState state = pinos_context_get_state (pinossrc->ctx);
 
-  GST_DEBUG ("got context state %d", state);
+  GST_DEBUG ("got context state %s", pinos_context_state_as_string (state));
 
   switch (state) {
     case PINOS_CONTEXT_STATE_UNCONNECTED:
@@ -1000,6 +1016,7 @@ gst_pinos_src_open (GstPinosSrc * pinossrc)
   while (TRUE) {
     PinosContextState state = pinos_context_get_state (pinossrc->ctx);
 
+    GST_DEBUG ("waiting for CONNECTED, now %s", pinos_context_state_as_string (state));
     if (state == PINOS_CONTEXT_STATE_CONNECTED)
       break;
 
diff --git a/pinos/modules/spa/spa-alsa-monitor.c b/pinos/modules/spa/spa-alsa-monitor.c
index 5a87d32f..a947985b 100644
--- a/pinos/modules/spa/spa-alsa-monitor.c
+++ b/pinos/modules/spa/spa-alsa-monitor.c
@@ -125,8 +125,8 @@ add_item (PinosSpaALSAMonitor *this, SpaMonitorItem *item)
     return;
   }
   if ((res = spa_handle_get_interface (handle, priv->uri.clock, &clock_iface)) < 0) {
-    g_error ("can't get CLOCK interface: %d", res);
-    return;
+    g_debug ("can't get CLOCK interface: %d", res);
+    clock_iface = NULL;
   }
 
   if (item->info) {
diff --git a/pinos/server/client-node.c b/pinos/server/client-node.c
index 4ae6b2ed..fce02e11 100644
--- a/pinos/server/client-node.c
+++ b/pinos/server/client-node.c
@@ -45,7 +45,7 @@
 #define MAX_INPUTS       64
 #define MAX_OUTPUTS      64
 
-#define MAX_BUFFERS      16
+#define MAX_BUFFERS      64
 
 #define CHECK_IN_PORT_ID(this,d,p)       ((d) == SPA_DIRECTION_INPUT && (p) < MAX_INPUTS)
 #define CHECK_OUT_PORT_ID(this,d,p)      ((d) == SPA_DIRECTION_OUTPUT && (p) < MAX_OUTPUTS)
@@ -57,16 +57,20 @@
 #define CHECK_OUT_PORT(this,d,p)         (CHECK_OUT_PORT_ID(this,d,p) && (this)->out_ports[p].valid)
 #define CHECK_PORT(this,d,p)             (CHECK_IN_PORT (this,d,p) || CHECK_OUT_PORT (this,d,p))
 
+#define CHECK_PORT_BUFFER(this,b,p)      (b < p->n_buffers)
+
 typedef struct _SpaProxy SpaProxy;
 typedef struct _ProxyBuffer ProxyBuffer;
 
 struct _ProxyBuffer {
-  SpaBuffer *outbuf;
-  SpaBuffer  buffer;
-  SpaMeta    metas[4];
-  SpaData    datas[4];
-  off_t      offset;
-  size_t     size;
+  SpaBuffer   *outbuf;
+  SpaBuffer    buffer;
+  SpaMeta      metas[4];
+  SpaData      datas[4];
+  off_t        offset;
+  size_t       size;
+  bool         outstanding;
+  ProxyBuffer *next;
 };
 
 typedef struct {
@@ -85,7 +89,6 @@ typedef struct {
   size_t         buffer_mem_size;
   void          *buffer_mem_ptr;
 
-  uint32_t       buffer_id;
   SpaQueue       ready;
 } SpaProxyPort;
 
@@ -654,7 +657,7 @@ spa_proxy_node_port_use_buffers (SpaNode         *node,
     b->buffer.datas = b->datas;
     b->buffer.metas = b->metas;
 
-    b->size = pinos_serialize_buffer_get_size (buffers[i]);
+    b->size = SPA_ROUND_UP_N (pinos_serialize_buffer_get_size (buffers[i]), 64);
     b->offset = size;
 
     for (j = 0; j < buffers[i]->n_metas; j++) {
@@ -810,7 +813,7 @@ copy_meta_in (SpaProxy *this, SpaProxyPort *port, uint32_t buffer_id)
   unsigned int i;
 
   for (i = 0; i < b->outbuf->n_metas; i++) {
-    SpaMeta *sm = &b->metas[i];
+    SpaMeta *sm = &b->buffer.metas[i];
     SpaMeta *dm = &b->outbuf->metas[i];
     memcpy (dm->data, sm->data, dm->size);
   }
@@ -852,7 +855,6 @@ spa_proxy_node_port_push_input (SpaNode          *node,
   SpaProxyPort *port;
   unsigned int i;
   bool have_error = false;
-  bool have_enough = false;
   PinosControlCmdProcessBuffer pb;
 
   if (node == NULL || n_info == 0 || info == NULL)
@@ -874,7 +876,7 @@ spa_proxy_node_port_push_input (SpaNode          *node,
       have_error = true;
       continue;
     }
-    if (info[i].buffer_id >= port->n_buffers) {
+    if (!CHECK_PORT_BUFFER (this, info[i].buffer_id, port)) {
       if (port->n_buffers == 0)
         info[i].status = SPA_RESULT_NO_BUFFERS;
       else
@@ -895,8 +897,6 @@ spa_proxy_node_port_push_input (SpaNode          *node,
 
   if (have_error)
     return SPA_RESULT_ERROR;
-  if (have_enough)
-    return SPA_RESULT_HAVE_ENOUGH_INPUT;
 
   if (!pinos_connection_flush (this->rtconn))
     spa_log_error (this->log, "proxy %p: error writing connection\n", this);
@@ -913,7 +913,6 @@ spa_proxy_node_port_pull_output (SpaNode           *node,
   SpaProxyPort *port;
   unsigned int i;
   bool have_error = false;
-  bool need_more = false;
 
   if (node == NULL || n_info == 0 || info == NULL)
     return SPA_RESULT_INVALID_ARGUMENTS;
@@ -921,6 +920,8 @@ spa_proxy_node_port_pull_output (SpaNode           *node,
   this = SPA_CONTAINER_OF (node, SpaProxy, node);
 
   for (i = 0; i < n_info; i++) {
+    ProxyBuffer *b;
+
     if (!CHECK_OUT_PORT (this, SPA_DIRECTION_OUTPUT, info[i].port_id)) {
       spa_log_warn (this->log, "invalid port %u\n", info[i].port_id);
       info[i].status = SPA_RESULT_INVALID_PORT;
@@ -936,15 +937,19 @@ spa_proxy_node_port_pull_output (SpaNode           *node,
       continue;
     }
 
-    info[i].buffer_id = port->buffer_id;
-    info[i].status = SPA_RESULT_OK;
+    SPA_QUEUE_POP_HEAD (&port->ready, ProxyBuffer, next, b);
+    if (b == NULL) {
+      info[i].status = SPA_RESULT_UNEXPECTED;
+      have_error = true;
+      continue;
+    }
+    b->outstanding = true;
 
-    port->buffer_id = SPA_ID_INVALID;
+    info[i].buffer_id = b->outbuf->id;
+    info[i].status = SPA_RESULT_OK;
   }
   if (have_error)
     return SPA_RESULT_ERROR;
-  if (need_more)
-    return SPA_RESULT_NEED_MORE_INPUT;
 
   return SPA_RESULT_OK;
 }
@@ -987,6 +992,7 @@ spa_proxy_node_port_send_command (SpaNode        *node,
                                   SpaNodeCommand *command)
 {
   SpaProxy *this;
+  SpaResult res = SPA_RESULT_OK;
 
   if (node == NULL || command == NULL)
     return SPA_RESULT_INVALID_ARGUMENTS;
@@ -994,11 +1000,34 @@ spa_proxy_node_port_send_command (SpaNode        *node,
   this = SPA_CONTAINER_OF (node, SpaProxy, node);
 
   switch (command->type) {
+    case SPA_NODE_COMMAND_INVALID:
+      return SPA_RESULT_INVALID_COMMAND;
+
+    case SPA_NODE_COMMAND_START:
+    case SPA_NODE_COMMAND_PAUSE:
+    case SPA_NODE_COMMAND_FLUSH:
+    case SPA_NODE_COMMAND_DRAIN:
+    case SPA_NODE_COMMAND_MARKER:
+    {
+      PinosControlCmdPortCommand cpc;
+
+      cpc.port_id = port_id;
+      cpc.command = command;
+      pinos_connection_add_cmd (this->rtconn, PINOS_CONTROL_CMD_PORT_COMMAND, &cpc);
+
+      if (!pinos_connection_flush (this->rtconn)) {
+        spa_log_error (this->log, "proxy %p: error writing connection\n", this);
+        res = SPA_RESULT_ERROR;
+      }
+      break;
+    }
+
     default:
       spa_log_warn (this->log, "unhandled command %d\n", command->type);
+      res = SPA_RESULT_NOT_IMPLEMENTED;
       break;
   }
-  return SPA_RESULT_NOT_IMPLEMENTED;
+  return res;
 }
 
 static SpaResult
@@ -1039,6 +1068,7 @@ parse_connection (SpaProxy   *this)
       case PINOS_CONTROL_CMD_SET_FORMAT:
       case PINOS_CONTROL_CMD_SET_PROPERTY:
       case PINOS_CONTROL_CMD_NODE_COMMAND:
+      case PINOS_CONTROL_CMD_PORT_COMMAND:
       case PINOS_CONTROL_CMD_PROCESS_BUFFER:
         spa_log_error (this->log, "proxy %p: got unexpected command %d\n", this, cmd);
         break;
@@ -1154,6 +1184,7 @@ parse_rtconnection (SpaProxy   *this)
       {
         PinosControlCmdProcessBuffer cmd;
         SpaProxyPort *port;
+        ProxyBuffer *b;
 
         if (!pinos_connection_parse_cmd (conn, &cmd))
           break;
@@ -1163,12 +1194,14 @@ parse_rtconnection (SpaProxy   *this)
 
         port = cmd.direction == SPA_DIRECTION_INPUT ? &this->in_ports[cmd.port_id] : &this->out_ports[cmd.port_id];
 
-        if (port->buffer_id != SPA_ID_INVALID)
-          spa_log_warn (this->log, "proxy %p: unprocessed buffer: %d\n", this, port->buffer_id);
+        if (!CHECK_PORT_BUFFER (this, cmd.buffer_id, port))
+          break;
 
         copy_meta_in (this, port, cmd.buffer_id);
 
-        port->buffer_id = cmd.buffer_id;
+        b = &port->buffers[cmd.buffer_id];
+        b->next = NULL;
+        SPA_QUEUE_PUSH_TAIL (&port->ready, ProxyBuffer, next, b);
         break;
       }
       case PINOS_CONTROL_CMD_NODE_EVENT:
@@ -1181,6 +1214,15 @@ parse_rtconnection (SpaProxy   *this)
         handle_node_event (this, cne.event);
         break;
       }
+      case PINOS_CONTROL_CMD_PORT_COMMAND:
+      {
+        PinosControlCmdPortCommand cm;
+
+        if (!pinos_connection_parse_cmd (conn, &cm))
+          break;
+
+        break;
+      }
     }
   }
 
diff --git a/pinos/server/daemon.c b/pinos/server/daemon.c
index 0d4901ec..eeb5b2ac 100644
--- a/pinos/server/daemon.c
+++ b/pinos/server/daemon.c
@@ -201,28 +201,14 @@ no_node:
 
 
 static void
-on_node_remove_signal (PinosNode   *node,
+on_link_port_unlinked (PinosLink   *link,
+                       PinosPort   *port,
                        PinosDaemon *this)
 {
-  g_debug ("daemon %p: node %p remove", this, node);
-}
+  g_debug ("daemon %p: link %p: port %p unlinked", this, link, port);
 
-static void
-on_link_input_unlinked (PinosLink   *link,
-                        PinosPort   *port,
-                        PinosDaemon *this)
-{
-  g_debug ("daemon %p: link %p: input unlinked", this, link);
-}
-
-static void
-on_link_output_unlinked (PinosLink   *link,
-                         PinosPort   *port,
-                         PinosDaemon *this)
-{
-  g_debug ("daemon %p: link %p: output unlinked", this, link);
-
-  try_link_port (link->input->node, link->input, this);
+  if (port->direction == PINOS_DIRECTION_OUTPUT && link->input)
+    try_link_port (link->input->node, link->input, this);
 }
 
 static void
@@ -300,9 +286,9 @@ try_link_port (PinosNode *node, PinosPort *port, PinosDaemon *this)
       goto error;
 
     if (port->direction == PINOS_DIRECTION_OUTPUT)
-      link = pinos_node_link (node, port, target, NULL, NULL, &error);
+      link = pinos_port_link (port, target, NULL, NULL, &error);
     else
-      link = pinos_node_link (target->node, target, port, NULL, NULL, &error);
+      link = pinos_port_link (target, port, NULL, NULL, &error);
 
     if (link == NULL)
       goto error;
@@ -311,9 +297,7 @@ try_link_port (PinosNode *node, PinosPort *port, PinosDaemon *this)
     if (client)
       pinos_client_add_object (client, G_OBJECT (link));
 
-    g_signal_connect (target->node, "remove", (GCallback) on_node_remove_signal, this);
-    g_signal_connect (link, "input-unlinked", (GCallback) on_link_input_unlinked, this);
-    g_signal_connect (link, "output-unlinked", (GCallback) on_link_output_unlinked, this);
+    g_signal_connect (link, "port-unlinked", (GCallback) on_link_port_unlinked, this);
     g_signal_connect (link, "notify::state", (GCallback) on_link_state_notify, this);
     pinos_link_activate (link);
 
@@ -771,6 +755,9 @@ pinos_daemon_find_port (PinosDaemon     *daemon,
   for (nodes = priv->nodes; nodes; nodes = g_list_next (nodes)) {
     PinosNode *n = nodes->data;
 
+    if (n->flags & PINOS_NODE_FLAG_REMOVING)
+      continue;
+
     g_debug ("node path \"%s\"", pinos_node_get_object_path (n));
 
     if (have_name) {
diff --git a/pinos/server/data-loop.c b/pinos/server/data-loop.c
index 59fae193..8db6cc28 100644
--- a/pinos/server/data-loop.c
+++ b/pinos/server/data-loop.c
@@ -17,15 +17,20 @@
  * Boston, MA 02110-1301, USA.
  */
 
+#include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
 #include <poll.h>
 #include <errno.h>
 #include <sys/eventfd.h>
+#include <limits.h>
+#include <sys/time.h>
+#include <sys/resource.h>
 
 #include <gio/gio.h>
 
 #include "spa/include/spa/ringbuffer.h"
+#include "pinos/client/rtkit.h"
 #include "pinos/server/data-loop.h"
 
 #define PINOS_DATA_LOOP_GET_PRIVATE(loop)  \
@@ -60,6 +65,7 @@ struct _PinosDataLoopPrivate
 
   gboolean running;
   pthread_t thread;
+
 };
 
 G_DEFINE_TYPE (PinosDataLoop, pinos_data_loop, G_TYPE_OBJECT);
@@ -74,6 +80,52 @@ enum
   LAST_SIGNAL
 };
 
+static void
+make_realtime (PinosDataLoop *this)
+{
+  struct sched_param sp;
+  GDBusConnection *system_bus;
+  GError *error = NULL;
+  struct rlimit rl;
+  int r, rtprio;
+  long long rttime;
+
+  rtprio = 20;
+  rttime = 20000;
+
+  spa_zero (sp);
+  sp.sched_priority = rtprio;
+
+  if (pthread_setschedparam (pthread_self(), SCHED_RR|SCHED_RESET_ON_FORK, &sp) == 0) {
+    g_debug ("SCHED_OTHER|SCHED_RESET_ON_FORK worked.");
+    return;
+  }
+  system_bus = g_bus_get_sync (G_BUS_TYPE_SYSTEM, NULL, NULL);
+
+  rl.rlim_cur = rl.rlim_max = rttime;
+  if ((r = setrlimit (RLIMIT_RTTIME, &rl)) < 0)
+    g_debug ("setrlimit() failed: %s", strerror (errno));
+
+  if (rttime >= 0) {
+    r = getrlimit (RLIMIT_RTTIME, &rl);
+    if (r >= 0 && (long long) rl.rlim_max > rttime) {
+      g_debug ("Clamping rlimit-rttime to %lld for RealtimeKit", rttime);
+      rl.rlim_cur = rl.rlim_max = rttime;
+
+      if ((r = setrlimit (RLIMIT_RTTIME, &rl)) < 0)
+        g_debug ("setrlimit() failed: %s", strerror (errno));
+    }
+  }
+
+  if (!pinos_rtkit_make_realtime (system_bus, 0, rtprio, &error)) {
+    g_debug ("could not make thread realtime: %s", error->message);
+    g_clear_error (&error);
+  } else {
+    g_debug ("thread made realtime");
+  }
+  g_object_unref (system_bus);
+}
+
 static void *
 loop (void *user_data)
 {
@@ -82,11 +134,14 @@ loop (void *user_data)
   SpaPoll *p = &this->poll;
   unsigned int i, j;
 
+  make_realtime (this);
+
   g_debug ("data-loop %p: enter thread", this);
   while (priv->running) {
     SpaPollNotifyData ndata;
     unsigned int n_idle = 0;
     int r;
+    struct timespec ts;
 
     /* prepare */
     for (i = 0; i < priv->n_poll; i++) {
@@ -161,6 +216,9 @@ loop (void *user_data)
       continue;
     }
 
+//    clock_gettime (CLOCK_MONOTONIC, &ts);
+//    fprintf (stderr, "%llu\n", SPA_TIMESPEC_TO_TIME (&ts));
+
     /* after */
     for (i = 0; i < priv->n_poll; i++) {
       SpaPollItem *p = &priv->poll[i];
@@ -284,9 +342,6 @@ do_remove_item (SpaPoll         *poll,
     if (!in_thread)
       wakeup_thread (this);
   }
-  if (priv->n_poll == 0) {
-    stop_thread (this, in_thread);
-  }
   return SPA_RESULT_OK;
 }
 
diff --git a/pinos/server/link.c b/pinos/server/link.c
index cd751e91..808f2a30 100644
--- a/pinos/server/link.c
+++ b/pinos/server/link.c
@@ -74,8 +74,7 @@ enum
 enum
 {
   SIGNAL_REMOVE,
-  SIGNAL_INPUT_UNLINKED,
-  SIGNAL_OUTPUT_UNLINKED,
+  SIGNAL_PORT_UNLINKED,
   LAST_SIGNAL
 };
 
@@ -388,10 +387,14 @@ do_allocation (PinosLink *this, SpaNodeState in_state, SpaNodeState out_state)
                  "error get input port info: %d", res);
     goto error;
   }
+  spa_debug_port_info (oinfo);
+  spa_debug_port_info (iinfo);
+
   in_flags = iinfo->flags;
   out_flags = oinfo->flags;
 
   if (out_flags & SPA_PORT_INFO_FLAG_LIVE) {
+    g_debug ("setting link as live");
     this->output->node->live = true;
     this->input->node->live = true;
   }
@@ -430,9 +433,6 @@ do_allocation (PinosLink *this, SpaNodeState in_state, SpaNodeState out_state)
   } else
     return SPA_RESULT_OK;
 
-  spa_debug_port_info (oinfo);
-  spa_debug_port_info (iinfo);
-
   if (priv->buffers == NULL) {
     SpaAllocParamBuffers *in_alloc, *out_alloc;
     guint max_buffers = MAX_BUFFERS;
@@ -486,7 +486,7 @@ do_allocation (PinosLink *this, SpaNodeState in_state, SpaNodeState out_state)
       }
       hdr_size += n_metas * sizeof (SpaMeta);
 
-      buf_size = hdr_size + minsize;
+      buf_size = SPA_ROUND_UP_N (hdr_size + minsize, 64);
 
       priv->n_buffers = max_buffers;
       pinos_memblock_alloc (PINOS_MEMBLOCK_FLAG_WITH_FD |
@@ -543,7 +543,7 @@ do_allocation (PinosLink *this, SpaNodeState in_state, SpaNodeState out_state)
           d->data = NULL;
         }
       }
-      g_debug ("allocated %d buffers %p", priv->n_buffers, priv->buffers);
+      g_debug ("allocated %d buffers %p %zd", priv->n_buffers, priv->buffers, minsize);
       priv->allocated = TRUE;
     }
 
@@ -665,11 +665,18 @@ do_start (PinosLink *this, SpaNodeState in_state, SpaNodeState out_state)
 }
 
 static SpaResult
-check_states (PinosLink *this, SpaResult res)
+check_states (PinosLink *this,
+              gpointer   user_data,
+              SpaResult  res)
 {
   SpaNodeState in_state, out_state;
   PinosLinkPrivate *priv = this->priv;
 
+  if (res != SPA_RESULT_OK) {
+    g_warning ("link %p: error: %d", this, res);
+    return res;
+  }
+
 again:
   if (this->input == NULL || this->output == NULL)
     return SPA_RESULT_OK;
@@ -745,15 +752,12 @@ typedef struct {
 } UnlinkedData;
 
 static void
-on_input_unlinked (UnlinkedData *data)
+on_port_unlinked (PinosPort *port, PinosLink *this, SpaResult res, gulong id)
 {
-  g_signal_emit (data->link, signals[SIGNAL_INPUT_UNLINKED], 0, data->port);
-}
+  g_signal_emit (this, signals[SIGNAL_PORT_UNLINKED], 0, port);
 
-static void
-on_output_unlinked (UnlinkedData *data)
-{
-  g_signal_emit (data->link, signals[SIGNAL_OUTPUT_UNLINKED], 0, data->port);
+  if (this->input == NULL || this->output == NULL)
+    pinos_link_update_state (this, PINOS_LINK_STATE_UNLINKED);
 }
 
 static void
@@ -761,57 +765,34 @@ on_node_remove (PinosNode *node, PinosLink *this)
 {
   PinosLinkPrivate *priv = this->priv;
   SpaResult res = SPA_RESULT_OK;
-  UnlinkedData data;
-
-  data.link = this;
+  PinosPort *port, *other;
 
   g_signal_handlers_disconnect_by_data (node, this);
-  if (node == this->input->node) {
-    if (this->input->allocated) {
-      priv->buffers = NULL;
-      priv->n_buffers = 0;
-
-      if ((res = spa_node_port_use_buffers (this->output->node->node,
-                                            SPA_DIRECTION_OUTPUT,
-                                            this->output->port,
-                                            priv->buffers,
-                                            priv->n_buffers)) < 0) {
-        g_warning ("link %p: failed to clear output buffers: %d", this, res);
-      }
-    }
-    data.port = this->input;
-    this->input = NULL;
-    pinos_main_loop_defer (priv->main_loop,
-                           this,
-                           res,
-                           (PinosDeferFunc) on_input_unlinked,
-                           g_memdup (&data, sizeof (UnlinkedData)),
-                           g_free);
-  } else {
-    if (this->output->allocated) {
-      priv->buffers = NULL;
-      priv->n_buffers = 0;
-
-      if ((res = spa_node_port_use_buffers (this->input->node->node,
-                                            SPA_DIRECTION_INPUT,
-                                            this->input->port,
-                                            priv->buffers,
-                                            priv->n_buffers)) < 0) {
-        g_warning ("link %p: failed to clear input buffers: %d", this, res);
-      }
-    }
-    data.port = this->output;
-    this->output = NULL;
-    pinos_main_loop_defer (priv->main_loop,
-                           this,
-                           res,
-                           (PinosDeferFunc) on_output_unlinked,
-                           g_memdup (&data, sizeof (UnlinkedData)),
-                           g_free);
+
+  if (this->input && node == this->input->node) {
+    port = this->input;
+    other = this->output;
+  } else if (this->output && node == this->output->node) {
+    port = this->output;
+    other = this->input;
+  } else
+    return;
+
+  if (port->allocated) {
+    priv->buffers = NULL;
+    priv->n_buffers = 0;
+
+    g_debug ("link %p: clear input allocated buffers on port %p", link, other);
+    pinos_port_clear_buffers (other);
   }
 
-  if (this->input == NULL || this->output == NULL)
-    pinos_link_update_state (this, PINOS_LINK_STATE_UNLINKED);
+  res = pinos_port_unlink (port, this);
+  pinos_main_loop_defer (priv->main_loop,
+                         port,
+                         res,
+                         (PinosDeferFunc) on_port_unlinked,
+                         g_object_ref (this),
+                         g_object_unref);
 }
 
 static void
@@ -854,28 +835,11 @@ pinos_link_dispose (GObject * object)
 
   g_signal_emit (this, signals[SIGNAL_REMOVE], 0, NULL);
 
-  if (this->input) {
-    if (!this->input->allocated) {
-      spa_node_port_use_buffers (this->input->node->node,
-                                 SPA_DIRECTION_INPUT,
-                                 this->input->port,
-                                 NULL, 0);
-      this->input->buffers = NULL;
-      this->input->n_buffers = 0;
-    }
-    this->input = NULL;
-  }
-  if (this->output) {
-    if (!this->output->allocated) {
-      spa_node_port_use_buffers (this->output->node->node,
-                                 SPA_DIRECTION_OUTPUT,
-                                 this->output->port,
-                                 NULL, 0);
-      this->output->buffers = NULL;
-      this->output->n_buffers = 0;
-    }
-    this->output = NULL;
-  }
+  if (this->input)
+    pinos_port_unlink (this->input, this);
+  if (this->output)
+    pinos_port_unlink (this->output, this);
+
   link_unregister_object (this);
 
   pinos_main_loop_defer_cancel (priv->main_loop, this, 0);
@@ -894,9 +858,8 @@ pinos_link_finalize (GObject * object)
   g_clear_object (&priv->iface);
   g_free (priv->object_path);
 
-  if (priv->allocated) {
+  if (priv->allocated)
     pinos_memblock_free (&priv->buffer_mem);
-  }
 
   G_OBJECT_CLASS (pinos_link_parent_class)->finalize (object);
 }
@@ -982,17 +945,7 @@ pinos_link_class_init (PinosLinkClass * klass)
                                          G_TYPE_NONE,
                                          0,
                                          G_TYPE_NONE);
-  signals[SIGNAL_INPUT_UNLINKED] = g_signal_new ("input-unlinked",
-                                         G_TYPE_FROM_CLASS (klass),
-                                         G_SIGNAL_RUN_LAST,
-                                         0,
-                                         NULL,
-                                         NULL,
-                                         g_cclosure_marshal_generic,
-                                         G_TYPE_NONE,
-                                         1,
-                                         G_TYPE_POINTER);
-  signals[SIGNAL_OUTPUT_UNLINKED] = g_signal_new ("output-unlinked",
+  signals[SIGNAL_PORT_UNLINKED] = g_signal_new ("port-unlinked",
                                          G_TYPE_FROM_CLASS (klass),
                                          G_SIGNAL_RUN_LAST,
                                          0,
@@ -1067,7 +1020,7 @@ pinos_link_activate (PinosLink *this)
   g_return_val_if_fail (PINOS_IS_LINK (this), FALSE);
 
   spa_ringbuffer_init (&this->ringbuffer, SPA_N_ELEMENTS (this->queue));
-  check_states (this, SPA_RESULT_OK);
+  check_states (this, NULL, SPA_RESULT_OK);
 
   return TRUE;
 }
diff --git a/pinos/server/link.h b/pinos/server/link.h
index 03b8cbd7..49df3981 100644
--- a/pinos/server/link.h
+++ b/pinos/server/link.h
@@ -53,7 +53,7 @@ struct _PinosLink {
   PinosPort    *output;
   PinosPort    *input;
 
-  uint32_t      queue[16];
+  uint32_t      queue[64];
   SpaRingbuffer ringbuffer;
   gint          in_ready;
 
diff --git a/pinos/server/main-loop.c b/pinos/server/main-loop.c
index daa7122c..375abc0b 100644
--- a/pinos/server/main-loop.c
+++ b/pinos/server/main-loop.c
@@ -389,11 +389,9 @@ process_work_queue (PinosMainLoop *this)
   for (item = priv->work.head, prev = NULL; item; prev = item, item = next) {
     next = item->next;
 
-    g_debug ("main-loop %p: peek work queue item %p seq %d, prev %p next %p", this, item->obj, item->seq, prev, next);
     if (item->seq != SPA_ID_INVALID)
       continue;
 
-    g_debug ("main-loop %p: process work item %p", this, item->obj);
     if (priv->work.tail == item)
       priv->work.tail = prev;
     if (prev == NULL)
@@ -401,8 +399,10 @@ process_work_queue (PinosMainLoop *this)
     else
       prev->next = next;
 
-    if (item->func)
+    if (item->func) {
+      g_debug ("main-loop %p: process work item %p", this, item->obj);
       item->func (item->obj, item->data, item->res, item->id);
+    }
     if (item->notify)
       item->notify (item->data);
 
@@ -484,7 +484,7 @@ pinos_main_loop_defer_cancel (PinosMainLoop  *loop,
     priv->work_id = g_idle_add ((GSourceFunc) process_work_queue, loop);
 }
 
-void
+gboolean
 pinos_main_loop_defer_complete (PinosMainLoop  *loop,
                                 gpointer        obj,
                                 uint32_t        seq,
@@ -494,11 +494,9 @@ pinos_main_loop_defer_complete (PinosMainLoop  *loop,
   PinosMainLoopPrivate *priv;
   gboolean have_work = FALSE;
 
-  g_return_if_fail (PINOS_IS_MAIN_LOOP (loop));
+  g_return_val_if_fail (PINOS_IS_MAIN_LOOP (loop), FALSE);
   priv = loop->priv;
 
-  g_debug ("main-loop %p: async complete %d %d for object %p", loop, seq, res, obj);
-
   for (item = priv->work.head; item; item = item->next) {
     if (item->obj == obj && item->seq == seq) {
       g_debug ("main-loop %p: found defered %d for object %p", loop, seq, obj);
@@ -512,6 +510,8 @@ pinos_main_loop_defer_complete (PinosMainLoop  *loop,
 
   if (priv->work_id == 0 && have_work)
     priv->work_id = g_idle_add ((GSourceFunc) process_work_queue, loop);
+
+  return have_work;
 }
 
 GMainLoop *
diff --git a/pinos/server/main-loop.h b/pinos/server/main-loop.h
index b480fc83..0b65e3ec 100644
--- a/pinos/server/main-loop.h
+++ b/pinos/server/main-loop.h
@@ -85,7 +85,7 @@ gulong              pinos_main_loop_defer                   (PinosMainLoop  *loo
 void                pinos_main_loop_defer_cancel            (PinosMainLoop  *loop,
                                                              gpointer        obj,
                                                              gulong          id);
-void                pinos_main_loop_defer_complete          (PinosMainLoop  *loop,
+gboolean            pinos_main_loop_defer_complete          (PinosMainLoop  *loop,
                                                              gpointer        obj,
                                                              uint32_t        seq,
                                                              SpaResult       res);
diff --git a/pinos/server/node.c b/pinos/server/node.c
index 981a2271..ae24726e 100644
--- a/pinos/server/node.c
+++ b/pinos/server/node.c
@@ -53,18 +53,6 @@ free_node_port (PinosPort *np)
   g_slice_free (PinosPort, np);
 }
 
-static PinosPort *
-find_node_port (GList *ports, PinosNode *node, uint32_t port)
-{
-  GList *walk;
-  for (walk = ports; walk; walk = g_list_next (walk)) {
-    PinosPort *np = walk->data;
-    if (np->node == node && np->port == port)
-      return np;
-  }
-  return NULL;
-}
-
 struct _PinosNodePrivate
 {
   PinosDaemon *daemon;
@@ -74,6 +62,8 @@ struct _PinosNodePrivate
   gchar *object_path;
   gchar *name;
 
+  uint32_t seq;
+
   gboolean async_init;
   unsigned int max_input_ports;
   unsigned int max_output_ports;
@@ -340,13 +330,11 @@ do_read_link (SpaPoll        *poll,
   size_t offset;
   SpaResult res;
 
-  if (spa_ringbuffer_get_read_offset (&link->ringbuffer, &offset) > 0) {
-    SpaPortInputInfo iinfo[1];
+  if (link->input == NULL)
+    return SPA_RESULT_OK;
 
-    if (link->in_ready <= 0 || link->input == NULL)
-      return SPA_RESULT_OK;
-
-    link->in_ready--;
+  while (link->in_ready > 0 && spa_ringbuffer_get_read_offset (&link->ringbuffer, &offset) > 0) {
+    SpaPortInputInfo iinfo[1];
 
     iinfo[0].port_id = link->input->port;
     iinfo[0].buffer_id = link->queue[offset];
@@ -356,6 +344,7 @@ do_read_link (SpaPoll        *poll,
       g_warning ("node %p: error pushing buffer: %d, %d", this, res, iinfo[0].status);
 
     spa_ringbuffer_read_advance (&link->ringbuffer, 1);
+    link->in_ready--;
   }
   return SPA_RESULT_OK;
 }
@@ -379,8 +368,8 @@ on_node_event (SpaNode *node, SpaNodeEvent *event, void *user_data)
       SpaNodeEventAsyncComplete *ac = (SpaNodeEventAsyncComplete *) event;
 
       g_debug ("node %p: async complete event %d %d", this, ac->seq, ac->res);
-      pinos_main_loop_defer_complete (priv->main_loop, this, ac->seq, ac->res);
-      g_signal_emit (this, signals[SIGNAL_ASYNC_COMPLETE], 0, ac->seq, ac->res);
+      if (!pinos_main_loop_defer_complete (priv->main_loop, this, ac->seq, ac->res))
+        g_signal_emit (this, signals[SIGNAL_ASYNC_COMPLETE], 0, ac->seq, ac->res);
       break;
     }
 
@@ -410,8 +399,8 @@ on_node_event (SpaNode *node, SpaNodeEvent *event, void *user_data)
       SpaNodeEventHaveOutput *ho = (SpaNodeEventHaveOutput *) event;
       SpaPortOutputInfo oinfo[1] = { 0, };
       SpaResult res;
-      gboolean pushed = FALSE;
       guint i;
+      gboolean pushed = FALSE;
 
       oinfo[0].port_id = ho->port_id;
 
@@ -422,9 +411,12 @@ on_node_event (SpaNode *node, SpaNodeEvent *event, void *user_data)
 
       for (i = 0; i < priv->rt.links->len; i++) {
         PinosLink *link = g_ptr_array_index (priv->rt.links, i);
+        PinosPort *output = link->output;
+        PinosPort *input = link->input;
         size_t offset;
 
-        if (link->output == NULL || link->output->port != ho->port_id)
+        if (output == NULL || input == NULL ||
+            output->node->node != node || output->port != ho->port_id)
           continue;
 
         if (spa_ringbuffer_get_write_offset (&link->ringbuffer, &offset) > 0) {
@@ -441,7 +433,6 @@ on_node_event (SpaNode *node, SpaNodeEvent *event, void *user_data)
         }
       }
       if (!pushed) {
-        g_debug ("node %p: discarded buffer %u", this, oinfo[0].buffer_id);
         if ((res = spa_node_port_reuse_buffer (node, oinfo[0].port_id, oinfo[0].buffer_id)) < 0)
           g_warning ("node %p: error reuse buffer: %d", node, res);
       }
@@ -456,7 +447,7 @@ on_node_event (SpaNode *node, SpaNodeEvent *event, void *user_data)
       for (i = 0; i < priv->rt.links->len; i++) {
         PinosLink *link = g_ptr_array_index (priv->rt.links, i);
 
-        if (link->input == NULL || link->input->port != rb->port_id)
+        if (link->input == NULL || link->input->port != rb->port_id || link->output == NULL)
           continue;
 
         if ((res = spa_node_port_reuse_buffer (link->output->node->node,
@@ -1015,7 +1006,11 @@ pinos_node_remove (PinosNode *node)
 {
   g_return_if_fail (PINOS_IS_NODE (node));
 
+  if (node->flags & PINOS_NODE_FLAG_REMOVING)
+    return;
+
   g_debug ("node %p: remove", node);
+  node->flags |= PINOS_NODE_FLAG_REMOVING;
   g_signal_emit (node, signals[SIGNAL_REMOVE], 0, NULL);
 }
 
@@ -1071,64 +1066,6 @@ pinos_node_get_free_port (PinosNode       *node,
 
 }
 
-static SpaResult
-do_remove_link (SpaPoll        *poll,
-                bool            async,
-                uint32_t        seq,
-                size_t          size,
-                void           *data,
-                void           *user_data)
-{
-  PinosNode *this = user_data;
-  PinosNodePrivate *priv = this->priv;
-  PinosLink *link = ((PinosLink**)data)[0];
-
-  g_ptr_array_remove_fast (priv->rt.links, link);
-
-  return SPA_RESULT_OK;
-}
-
-static void
-on_remove_link (PinosLink *link, PinosNode *node)
-{
-  PinosPort *p;
-  PinosNode *n;
-
-  if (link->output) {
-    n = link->output->node;
-    if ((p = find_node_port (n->priv->output_ports, n, link->output->port)))
-      if (g_ptr_array_remove_fast (p->links, link))
-        n->priv->n_used_output_links--;
-
-      spa_poll_invoke (&n->priv->data_loop->poll,
-                       do_remove_link,
-                       SPA_ID_INVALID,
-                       sizeof (PinosLink *),
-                       &link,
-                       n);
-
-    if (n->priv->n_used_output_links == 0 &&
-        n->priv->n_used_input_links == 0)
-      pinos_node_report_idle (n);
-  }
-  if (link->input->node) {
-    n = link->input->node;
-    if ((p = find_node_port (n->priv->input_ports, n, link->input->port)))
-      if (g_ptr_array_remove_fast (p->links, link))
-        n->priv->n_used_input_links--;
-
-      spa_poll_invoke (&n->priv->data_loop->poll,
-                       do_remove_link,
-                       SPA_ID_INVALID,
-                       sizeof (PinosLink *),
-                       &link,
-                       n);
-
-    if (n->priv->n_used_output_links == 0 &&
-        n->priv->n_used_input_links == 0)
-      pinos_node_report_idle (n);
-  }
-}
 
 static SpaResult
 do_add_link (SpaPoll        *poll,
@@ -1147,67 +1084,79 @@ do_add_link (SpaPoll        *poll,
   return SPA_RESULT_OK;
 }
 
+static PinosLink *
+find_link (PinosPort *output_port, PinosPort *input_port)
+{
+  guint i;
+
+  for (i = 0; i < output_port->links->len; i++) {
+    PinosLink *pl = g_ptr_array_index (output_port->links, i);
+    if (pl->input == input_port) {
+      return pl;
+    }
+  }
+  return NULL;
+}
+
+PinosLink *
+pinos_port_get_link (PinosPort       *output_port,
+                     PinosPort       *input_port)
+{
+  g_return_val_if_fail (output_port != NULL, NULL);
+  g_return_val_if_fail (input_port != NULL, NULL);
+
+  return find_link (output_port, input_port);
+}
+
 /**
- * pinos_node_link:
- * @output_node: a #PinosNode
+ * pinos_port_link:
  * @output_port: an output port
  * @input_port: an input port
  * @format_filter: a format filter
  * @properties: extra properties
  * @error: an error or %NULL
  *
- * Make a link between @output_port and @input_port with the given ids
+ * Make a link between @output_port and @input_port
  *
  * If the ports were already linked, the existing links will be returned.
  *
- * If the output id was linked to a different input node or id, it
- * will be relinked.
- *
  * Returns: a new #PinosLink or %NULL and @error is set.
  */
 PinosLink *
-pinos_node_link (PinosNode       *output_node,
-                 PinosPort       *output_port,
+pinos_port_link (PinosPort       *output_port,
                  PinosPort       *input_port,
                  GPtrArray       *format_filter,
                  PinosProperties *properties,
                  GError         **error)
 {
   PinosNodePrivate *priv;
-  PinosNode *input_node;
-  PinosLink *link = NULL;
-  guint i;
+  PinosNode *input_node, *output_node;
+  PinosLink *link;
 
-  g_return_val_if_fail (PINOS_IS_NODE (output_node), NULL);
   g_return_val_if_fail (output_port != NULL, NULL);
   g_return_val_if_fail (input_port != NULL, NULL);
 
+  output_node = output_port->node;
   priv = output_node->priv;
   input_node = input_port->node;
 
-  g_debug ("node %p: link %u %p:%u", output_node, output_port->port, input_node, input_port->port);
+  g_debug ("port link %p:%u -> %p:%u", output_node, output_port->port, input_node, input_port->port);
 
   if (output_node == input_node)
     goto same_node;
 
-  for (i = 0; i < output_port->links->len; i++) {
-    PinosLink *pl = g_ptr_array_index (output_port->links, i);
-    if (pl->input->node == input_node && pl->input == input_port) {
-      link = pl;
-      break;
-    }
-  }
+  if (input_port->links->len > 0)
+    goto was_linked;
+
+  link = find_link (output_port, input_port);
 
   if (link)  {
-    /* FIXME */
-    link->input->node = input_node;
-    link->input = input_port;
     g_object_ref (link);
   } else {
     input_node->live = output_node->live;
     if (output_node->clock)
       input_node->clock = output_node->clock;
-    g_debug ("node %p: clock %p", output_node, output_node->clock);
+    g_debug ("node %p: clock %p, live %d", output_node, output_node->clock, output_node->live);
 
     link = g_object_new (PINOS_TYPE_LINK,
                        "daemon", priv->daemon,
@@ -1217,11 +1166,6 @@ pinos_node_link (PinosNode       *output_node,
                        "properties", properties,
                        NULL);
 
-    g_signal_connect (link,
-                      "remove",
-                      (GCallback) on_remove_link,
-                      output_node);
-
     g_ptr_array_add (output_port->links, link);
     g_ptr_array_add (input_port->links, link);
 
@@ -1251,6 +1195,187 @@ same_node:
                  "can't link a node to itself");
     return NULL;
   }
+was_linked:
+  {
+    g_set_error (error,
+                 PINOS_ERROR,
+                 PINOS_ERROR_NODE_LINK,
+                 "input port was already linked");
+    return NULL;
+  }
+}
+
+static SpaResult
+pinos_port_pause (PinosPort *port)
+{
+  SpaNodeCommand cmd;
+
+  cmd.type = SPA_NODE_COMMAND_PAUSE;
+  cmd.size = sizeof (cmd);
+  return spa_node_port_send_command (port->node->node,
+                                    port->direction,
+                                    port->port,
+                                    &cmd);
+}
+
+static SpaResult
+do_remove_link_done (SpaPoll        *poll,
+                     bool            async,
+                     uint32_t        seq,
+                     size_t          size,
+                     void           *data,
+                     void           *user_data)
+{
+  PinosPort *port = user_data;
+  PinosNode *this = port->node;
+  PinosNodePrivate *priv = this->priv;
+  PinosLink *link = ((PinosLink**)data)[0];
+
+  g_debug ("port %p: finish unlink", port);
+  if (port->direction == PINOS_DIRECTION_OUTPUT) {
+    if (g_ptr_array_remove_fast (port->links, link))
+      priv->n_used_output_links--;
+    link->output = NULL;
+  } else {
+    if (g_ptr_array_remove_fast (port->links, link))
+      priv->n_used_input_links--;
+    link->input = NULL;
+  }
+
+  if (priv->n_used_output_links == 0 &&
+      priv->n_used_input_links == 0) {
+    pinos_node_report_idle (this);
+  }
+
+  if (!port->allocated) {
+    g_debug ("port %p: clear buffers on port", port);
+    spa_node_port_use_buffers (port->node->node,
+                               port->direction,
+                               port->port,
+                               NULL, 0);
+    port->buffers = NULL;
+    port->n_buffers = 0;
+  }
+
+  pinos_main_loop_defer_complete (priv->main_loop,
+                                  port,
+                                  seq,
+                                  SPA_RESULT_OK);
+  g_object_unref (link);
+  g_object_unref (port->node);
+
+  return SPA_RESULT_OK;
+}
+
+static SpaResult
+do_remove_link (SpaPoll        *poll,
+                bool            async,
+                uint32_t        seq,
+                size_t          size,
+                void           *data,
+                void           *user_data)
+{
+  PinosPort *port = user_data;
+  PinosNode *this = port->node;
+  PinosNodePrivate *priv = this->priv;
+  PinosLink *link = ((PinosLink**)data)[0];
+  SpaResult res;
+
+  pinos_port_pause (port);
+
+  g_ptr_array_remove_fast (priv->rt.links, link);
+
+  res = spa_poll_invoke (&priv->main_loop->poll,
+                         do_remove_link_done,
+                         seq,
+                         sizeof (PinosLink *),
+                         &link,
+                         port);
+  return res;
+}
+
+SpaResult
+pinos_port_unlink (PinosPort *port, PinosLink *link)
+{
+  SpaResult res;
+
+  g_debug ("port %p: start unlink %p", port, link);
+
+  g_object_ref (link);
+  g_object_ref (port->node);
+  res = spa_poll_invoke (&port->node->priv->data_loop->poll,
+                         do_remove_link,
+                         port->node->priv->seq++,
+                         sizeof (PinosLink *),
+                         &link,
+                         port);
+  return res;
+}
+
+static SpaResult
+do_clear_buffers_done (SpaPoll        *poll,
+                       bool            async,
+                       uint32_t        seq,
+                       size_t          size,
+                       void           *data,
+                       void           *user_data)
+{
+  PinosPort *port = user_data;
+  PinosNode *this = port->node;
+  PinosNodePrivate *priv = this->priv;
+  SpaResult res;
+
+  g_debug ("port %p: clear buffers finish", port);
+
+  res = spa_node_port_use_buffers (port->node->node,
+                                   port->direction,
+                                   port->port,
+                                   NULL, 0);
+  port->buffers = NULL;
+  port->n_buffers = 0;
+
+  pinos_main_loop_defer_complete (priv->main_loop,
+                                  port,
+                                  seq,
+                                  res);
+  return res;
+}
+
+static SpaResult
+do_clear_buffers (SpaPoll        *poll,
+                  bool            async,
+                  uint32_t        seq,
+                  size_t          size,
+                  void           *data,
+                  void           *user_data)
+{
+  PinosPort *port = user_data;
+  PinosNode *this = port->node;
+  PinosNodePrivate *priv = this->priv;
+  SpaResult res;
+
+  pinos_port_pause (port);
+
+  res = spa_poll_invoke (&priv->main_loop->poll,
+                         do_clear_buffers_done,
+                         seq,
+                         0, NULL,
+                         port);
+  return res;
+}
+
+SpaResult
+pinos_port_clear_buffers (PinosPort *port)
+{
+  SpaResult res;
+
+  g_debug ("port %p: clear buffers", port);
+  res = spa_poll_invoke (&port->node->priv->data_loop->poll,
+                         do_clear_buffers,
+                         port->node->priv->seq++,
+                         0, NULL,
+                         port);
+  return res;
 }
 
 /**
diff --git a/pinos/server/node.h b/pinos/server/node.h
index 7632c76a..f4f95a6a 100644
--- a/pinos/server/node.h
+++ b/pinos/server/node.h
@@ -29,6 +29,12 @@ typedef struct _PinosNode PinosNode;
 typedef struct _PinosNodeClass PinosNodeClass;
 typedef struct _PinosNodePrivate PinosNodePrivate;
 
+
+typedef enum {
+  PINOS_NODE_FLAG_NONE          = 0,
+  PINOS_NODE_FLAG_REMOVING      = (1 << 0),
+} PinosNodeFlags;
+
 #include <spa/include/spa/node.h>
 
 #include <pinos/client/introspect.h>
@@ -65,6 +71,8 @@ struct _PinosPort {
 struct _PinosNode {
   GObject object;
 
+  PinosNodeFlags flags;
+
   SpaNode *node;
 
   bool live;
@@ -101,12 +109,6 @@ const gchar *       pinos_node_get_object_path         (PinosNode        *node);
 PinosPort *         pinos_node_get_free_port           (PinosNode        *node,
                                                         PinosDirection    direction);
 
-PinosLink *         pinos_node_link                    (PinosNode        *output_node,
-                                                        PinosPort        *output_port,
-                                                        PinosPort        *input_port,
-                                                        GPtrArray        *format_filter,
-                                                        PinosProperties  *properties,
-                                                        GError          **error);
 GList *             pinos_node_get_ports               (PinosNode        *node,
                                                         PinosDirection    direction);
 
@@ -118,6 +120,17 @@ void                pinos_node_report_error            (PinosNode *node, GError
 void                pinos_node_report_idle             (PinosNode *node);
 void                pinos_node_report_busy             (PinosNode *node);
 
+PinosLink *         pinos_port_link                    (PinosPort        *output_port,
+                                                        PinosPort        *input_port,
+                                                        GPtrArray        *format_filter,
+                                                        PinosProperties  *properties,
+                                                        GError          **error);
+SpaResult           pinos_port_unlink                  (PinosPort        *port,
+                                                        PinosLink        *link);
+
+SpaResult           pinos_port_clear_buffers           (PinosPort        *port);
+
+
 G_END_DECLS
 
 #endif /* __PINOS_NODE_H__ */
diff --git a/spa/include/spa/defs.h b/spa/include/spa/defs.h
index ca56dc9b..3dcc3016 100644
--- a/spa/include/spa/defs.h
+++ b/spa/include/spa/defs.h
@@ -116,6 +116,8 @@ typedef void (*SpaNotify) (void *data);
 # define SPA_PRINTF_FUNC(fmt, arg1)
 #endif
 
+#define SPA_ROUND_UP_N(num,align) ((((num) + ((align) - 1)) & ~((align) - 1)))
+
 #ifndef SPA_LIKELY
 #ifdef __GNUC__
 #define SPA_LIKELY(x) (__builtin_expect(!!(x),1))
@@ -126,7 +128,6 @@ typedef void (*SpaNotify) (void *data);
 #endif
 #endif
 
-
 #define spa_return_if_fail(expr)                                        \
     do {                                                                \
         if (SPA_UNLIKELY (!(expr)))                                     \
@@ -150,6 +151,8 @@ typedef void (*SpaNotify) (void *data);
 /* Does exactly nothing */
 #define spa_nop() do {} while (false)
 
+#define spa_memzero(x,l) (memset((x), 0, (l)))
+#define spa_zero(x) (spa_memzero(&(x), sizeof(x)))
 
 #ifdef __cplusplus
 }  /* extern "C" */
diff --git a/spa/include/spa/log.h b/spa/include/spa/log.h
index 8bd3f726..01c8f953 100644
--- a/spa/include/spa/log.h
+++ b/spa/include/spa/log.h
@@ -111,8 +111,8 @@ struct _SpaLog {
 
 #if __STDC_VERSION__ >= 199901L
 
-#define spa_log_log(l,lev,...)          \
-  if ((l) && (l)->level >= lev)         \
+#define spa_log_log(l,lev,...)                          \
+  if (SPA_UNLIKELY (spa_log_level_enabled (l, lev)))    \
     (l)->log((l),lev,__VA_ARGS__)
 
 #define spa_log_error(l,...)           spa_log_log(l,SPA_LOG_LEVEL_ERROR,__FILE__,__LINE__,__func__,__VA_ARGS__)
@@ -126,7 +126,7 @@ struct _SpaLog {
 #define SPA_LOG_FUNC(name,lev)                                                  \
 static inline void spa_log_##name (SpaLog *l, const char *format, ...)          \
 {                                                                               \
-  if (spa_log_level_enabled (l, lev)) {                                         \
+  if (SPA_UNLIKELY (spa_log_level_enabled (l, lev))) {                          \
     va_list varargs;                                                            \
     va_start (varargs, format);                                                 \
     (l)->logv((l),lev,__FILE__,__LINE__,__func__,format,varargs);               \
diff --git a/spa/include/spa/queue.h b/spa/include/spa/queue.h
index 7bdd7225..ca504160 100644
--- a/spa/include/spa/queue.h
+++ b/spa/include/spa/queue.h
@@ -52,6 +52,9 @@ struct _SpaQueue {
     (q)->length++;                              \
   } while (0);
 
+#define SPA_QUEUE_PEEK_HEAD(q,t,i)              \
+    ((i) = (t*)((q)->head));
+
 #define SPA_QUEUE_POP_HEAD(q,t,next,i)          \
   do {                                          \
     if (((i) = (t*)((q)->head)) == NULL)        \
diff --git a/spa/include/spa/ringbuffer.h b/spa/include/spa/ringbuffer.h
index ef5743ef..045700a9 100644
--- a/spa/include/spa/ringbuffer.h
+++ b/spa/include/spa/ringbuffer.h
@@ -67,7 +67,7 @@ static inline SpaResult
 spa_ringbuffer_init (SpaRingbuffer *rbuf,
                      size_t size)
 {
-  if ((size & (size - 1)) != 0)
+  if (SPA_UNLIKELY ((size & (size - 1)) != 0))
     return SPA_RESULT_ERROR;
 
   rbuf->size = size;
@@ -127,7 +127,7 @@ spa_ringbuffer_get_read_areas (SpaRingbuffer      *rbuf,
   areas[0].offset = r;
   areas[1].offset = 0;
 
-  if (end > rbuf->size) {
+  if (SPA_UNLIKELY (end > rbuf->size)) {
     areas[0].len = rbuf->size - r;
     areas[1].len = end - rbuf->size;
   } else {
@@ -185,7 +185,7 @@ spa_ringbuffer_get_write_areas (SpaRingbuffer      *rbuf,
   areas[0].offset = w;
   areas[1].offset = 0;
 
-  if (end > rbuf->size) {
+  if (SPA_UNLIKELY (end > rbuf->size)) {
     areas[0].len = rbuf->size - w;
     areas[1].len = end - rbuf->size;
   } else {
diff --git a/spa/plugins/alsa/alsa-monitor.c b/spa/plugins/alsa/alsa-monitor.c
index ab961b07..37ecf2f3 100644
--- a/spa/plugins/alsa/alsa-monitor.c
+++ b/spa/plugins/alsa/alsa-monitor.c
@@ -25,6 +25,7 @@
 #include <poll.h>
 
 #include <libudev.h>
+#include <asoundlib.h>
 
 #include <spa/log.h>
 #include <spa/id-map.h>
@@ -32,6 +33,7 @@
 #include <spa/monitor.h>
 #include <spa/debug.h>
 
+extern const SpaHandleFactory spa_alsa_sink_factory;
 extern const SpaHandleFactory spa_alsa_source_factory;
 
 typedef struct _SpaALSAMonitor SpaALSAMonitor;
@@ -98,11 +100,16 @@ path_get_card_id (const char *path)
   return e + 5;
 }
 
+#define CHECK(s,msg) if ((err = (s)) < 0) { spa_log_error (state->log, msg ": %s\n", snd_strerror(err)); return err; }
+
 static int
-fill_item (ALSAItem *item, struct udev_device *udevice)
+fill_item (SpaALSAMonitor *this, ALSAItem *item, struct udev_device *udevice)
 {
+  int err;
   unsigned int i;
   const char *str;
+  snd_pcm_t *hndl;
+  char device[64];
 
   if (item->udevice)
     udev_device_unref (item->udevice);
@@ -120,12 +127,39 @@ fill_item (ALSAItem *item, struct udev_device *udevice)
   if ((str = path_get_card_id (udev_device_get_property_value (udevice, "DEVPATH"))) == NULL)
     return -1;
 
+  snprintf (device, 63, "hw:%s", str);
+
+  if ((err = snd_pcm_open (&hndl,
+                    device,
+                    SND_PCM_STREAM_PLAYBACK,
+                    SND_PCM_NONBLOCK |
+                    SND_PCM_NO_AUTO_RESAMPLE |
+                    SND_PCM_NO_AUTO_CHANNELS |
+                    SND_PCM_NO_AUTO_FORMAT)) < 0) {
+    spa_log_error (this->log, "PLAYBACK open failed: %s\n", snd_strerror(err));
+    if ((err = snd_pcm_open (&hndl,
+                      device,
+                      SND_PCM_STREAM_CAPTURE,
+                      SND_PCM_NONBLOCK |
+                      SND_PCM_NO_AUTO_RESAMPLE |
+                      SND_PCM_NO_AUTO_CHANNELS |
+                      SND_PCM_NO_AUTO_FORMAT)) < 0) {
+      spa_log_error (this->log, "CAPTURE open failed: %s\n", snd_strerror(err));
+      return -1;
+    } else {
+      item->item.factory = &spa_alsa_source_factory;
+      snd_pcm_close (hndl);
+    }
+  } else {
+    item->item.factory = &spa_alsa_sink_factory;
+    snd_pcm_close (hndl);
+  }
+
   item->item.id = udev_device_get_syspath (item->udevice);
   item->item.flags = 0;
   item->item.state = SPA_MONITOR_ITEM_STATE_AVAILABLE;
   item->item.klass = "Audio/Device";
   item->item.info = &item->info;
-  item->item.factory = &spa_alsa_source_factory;
 
   item->info.items = item->info_items;
   i = 0;
@@ -219,7 +253,7 @@ alsa_on_fd_events (SpaPollNotifyData *data)
   SpaMonitorItem *item;
 
   dev = udev_monitor_receive_device (this->umonitor);
-  if (fill_item (&this->uitem, dev) < 0)
+  if (fill_item (this, &this->uitem, dev) < 0)
     return 0;
 
   if ((str = udev_device_get_action (dev)) == NULL)
@@ -325,7 +359,7 @@ again:
   }
 
   if (*state == (void*)1) {
-    fill_item (&this->uitem, NULL);
+    fill_item (this, &this->uitem, NULL);
     return SPA_RESULT_ENUM_END;
   }
 
@@ -335,7 +369,7 @@ again:
   if ((*state = udev_list_entry_get_next (devices)) == NULL)
     *state = (void*)1;
 
-  if (fill_item (&this->uitem, dev) < 0)
+  if (fill_item (this, &this->uitem, dev) < 0)
     goto again;
 
   *item = &this->uitem.item;
diff --git a/spa/plugins/alsa/alsa-sink.c b/spa/plugins/alsa/alsa-sink.c
index 4274e444..acc4a12d 100644
--- a/spa/plugins/alsa/alsa-sink.c
+++ b/spa/plugins/alsa/alsa-sink.c
@@ -32,7 +32,7 @@ typedef struct _SpaALSAState SpaALSASink;
 
 static const char default_device[] = "default";
 static const uint32_t default_buffer_time = 10000;
-static const uint32_t default_period_time = 5000;
+static const uint32_t default_period_time = 1000;
 static const bool default_period_event = 0;
 
 static void
@@ -47,6 +47,7 @@ reset_alsa_sink_props (SpaALSAProps *props)
 static void
 update_state (SpaALSASink *this, SpaNodeState state)
 {
+  spa_log_info (this->log, "update state %d\n", state);
   this->node.state = state;
 }
 
@@ -150,6 +151,62 @@ spa_alsa_sink_node_set_props (SpaNode         *node,
 }
 
 static SpaResult
+do_send_event (SpaPoll        *poll,
+               bool            async,
+               uint32_t        seq,
+               size_t          size,
+               void           *data,
+               void           *user_data)
+{
+  SpaALSASink *this = user_data;
+
+  this->event_cb (&this->node, data, this->user_data);
+
+  return SPA_RESULT_OK;
+}
+
+static SpaResult
+do_command (SpaPoll        *poll,
+            bool            async,
+            uint32_t        seq,
+            size_t          size,
+            void           *data,
+            void           *user_data)
+{
+  SpaALSASink *this = user_data;
+  SpaResult res;
+  SpaNodeCommand *cmd = data;
+  SpaNodeEventAsyncComplete ac;
+
+  switch (cmd->type) {
+    case SPA_NODE_COMMAND_START:
+    case SPA_NODE_COMMAND_PAUSE:
+      res = spa_node_port_send_command (&this->node,
+                                        SPA_DIRECTION_INPUT,
+                                        0,
+                                        cmd);
+      break;
+    default:
+      res = SPA_RESULT_NOT_IMPLEMENTED;
+      break;
+  }
+
+  if (async) {
+    ac.event.type = SPA_NODE_EVENT_TYPE_ASYNC_COMPLETE;
+    ac.event.size = sizeof (SpaNodeEventAsyncComplete);
+    ac.seq = seq;
+    ac.res = res;
+    spa_poll_invoke (this->main_loop,
+                     do_send_event,
+                     SPA_ID_INVALID,
+                     sizeof (ac),
+                     &ac,
+                     this);
+  }
+  return res;
+}
+
+static SpaResult
 spa_alsa_sink_node_send_command (SpaNode        *node,
                                  SpaNodeCommand *command)
 {
@@ -165,15 +222,22 @@ spa_alsa_sink_node_send_command (SpaNode        *node,
       return SPA_RESULT_INVALID_COMMAND;
 
     case SPA_NODE_COMMAND_START:
-      spa_alsa_start (this);
-
-      update_state (this, SPA_NODE_STATE_STREAMING);
-      break;
     case SPA_NODE_COMMAND_PAUSE:
-      spa_alsa_pause (this);
+    {
+      if (!this->have_format)
+        return SPA_RESULT_NO_FORMAT;
 
-      update_state (this, SPA_NODE_STATE_PAUSED);
-      break;
+      if (this->n_buffers == 0)
+        return SPA_RESULT_NO_BUFFERS;
+
+      return spa_poll_invoke (this->data_loop,
+                              do_command,
+                              ++this->seq,
+                              command->size,
+                              command,
+                              this);
+
+    }
     case SPA_NODE_COMMAND_FLUSH:
     case SPA_NODE_COMMAND_DRAIN:
     case SPA_NODE_COMMAND_MARKER:
@@ -298,6 +362,16 @@ spa_alsa_sink_node_port_enum_formats (SpaNode         *node,
 }
 
 static SpaResult
+spa_alsa_clear_buffers (SpaALSASink *this)
+{
+  if (this->n_buffers > 0) {
+    SPA_QUEUE_INIT (&this->ready);
+    this->n_buffers = 0;
+  }
+  return SPA_RESULT_OK;
+}
+
+static SpaResult
 spa_alsa_sink_node_port_set_format (SpaNode            *node,
                                     SpaDirection        direction,
                                     uint32_t            port_id,
@@ -316,8 +390,11 @@ spa_alsa_sink_node_port_set_format (SpaNode            *node,
     return SPA_RESULT_INVALID_PORT;
 
   if (format == NULL) {
+    spa_log_info (this->log, "clear format\n");
+    spa_alsa_pause (this, false);
+    spa_alsa_clear_buffers (this);
+    spa_alsa_close (this);
     this->have_format = false;
-    this->n_buffers = 0;
     update_state (this, SPA_NODE_STATE_CONFIGURE);
     return SPA_RESULT_OK;
   }
@@ -325,22 +402,27 @@ spa_alsa_sink_node_port_set_format (SpaNode            *node,
   if ((res = spa_format_audio_parse (format, &this->current_format)) < 0)
     return res;
 
-  if (spa_alsa_set_format (this, &this->current_format, false) < 0)
+  if (spa_alsa_set_format (this, &this->current_format, flags) < 0)
     return SPA_RESULT_ERROR;
 
-  this->info.flags = SPA_PORT_INFO_FLAG_CAN_USE_BUFFERS;
-  this->info.maxbuffering = -1;
-  this->info.latency = -1;
-  this->info.n_params = 1;
+  this->info.flags = SPA_PORT_INFO_FLAG_CAN_USE_BUFFERS |
+                     SPA_PORT_INFO_FLAG_LIVE;
+  this->info.maxbuffering = this->buffer_frames * this->frame_size;
+  this->info.latency = (this->period_frames * SPA_NSEC_PER_SEC) / this->rate;
+  this->info.n_params = 2;
   this->info.params = this->params;
   this->params[0] = &this->param_buffers.param;
   this->param_buffers.param.type = SPA_ALLOC_PARAM_TYPE_BUFFERS;
   this->param_buffers.param.size = sizeof (this->param_buffers);
-  this->param_buffers.minsize = 1;
+  this->param_buffers.minsize = this->period_frames * this->frame_size;
   this->param_buffers.stride = 0;
   this->param_buffers.min_buffers = 1;
-  this->param_buffers.max_buffers = 8;
+  this->param_buffers.max_buffers = 32;
   this->param_buffers.align = 16;
+  this->params[1] = &this->param_meta.param;
+  this->param_meta.param.type = SPA_ALLOC_PARAM_TYPE_META_ENABLE;
+  this->param_meta.param.size = sizeof (this->param_meta);
+  this->param_meta.type = SPA_META_TYPE_HEADER;
   this->info.extra = NULL;
 
   this->have_format = true;
@@ -419,7 +501,54 @@ spa_alsa_sink_node_port_use_buffers (SpaNode         *node,
                                      SpaBuffer      **buffers,
                                      uint32_t         n_buffers)
 {
-  return SPA_RESULT_NOT_IMPLEMENTED;
+  SpaALSASink *this;
+  int i;
+
+  if (node == NULL)
+    return SPA_RESULT_INVALID_ARGUMENTS;
+
+  if (!CHECK_PORT (this, direction, port_id))
+    return SPA_RESULT_INVALID_PORT;
+
+  this = SPA_CONTAINER_OF (node, SpaALSASink, node);
+
+  spa_log_info (this->log, "use buffers %d\n", n_buffers);
+
+  if (!this->have_format)
+    return SPA_RESULT_NO_FORMAT;
+
+  if (n_buffers == 0) {
+    spa_alsa_pause (this, false);
+    spa_alsa_clear_buffers (this);
+    update_state (this, SPA_NODE_STATE_READY);
+    return SPA_RESULT_OK;
+  }
+
+  for (i = 0; i < n_buffers; i++) {
+    SpaALSABuffer *b = &this->buffers[i];
+    b->outbuf = buffers[i];
+    b->outstanding = true;
+
+    b->h = spa_buffer_find_meta (b->outbuf, SPA_META_TYPE_HEADER);
+
+    switch (buffers[i]->datas[0].type) {
+      case SPA_DATA_TYPE_MEMFD:
+      case SPA_DATA_TYPE_DMABUF:
+      case SPA_DATA_TYPE_MEMPTR:
+        if (buffers[i]->datas[0].data == NULL) {
+          spa_log_error (this->log, "alsa-source: need mapped memory\n");
+          continue;
+        }
+        break;
+      default:
+        break;
+    }
+  }
+  this->n_buffers = n_buffers;
+
+  update_state (this, SPA_NODE_STATE_PAUSED);
+
+  return SPA_RESULT_OK;
 }
 
 static SpaResult
@@ -475,7 +604,7 @@ spa_alsa_sink_node_port_push_input (SpaNode          *node,
 {
   SpaALSASink *this;
   unsigned int i;
-  bool have_error = false, have_enough = false;
+  bool have_error = false;
 
   if (node == NULL || n_info == 0 || info == NULL)
     return SPA_RESULT_INVALID_ARGUMENTS;
@@ -483,32 +612,38 @@ spa_alsa_sink_node_port_push_input (SpaNode          *node,
   this = SPA_CONTAINER_OF (node, SpaALSASink, node);
 
   for (i = 0; i < n_info; i++) {
+    SpaALSABuffer *b;
+
     if (info[i].port_id != 0) {
       info[i].status = SPA_RESULT_INVALID_PORT;
       have_error = true;
       continue;
     }
+    if (!this->have_format) {
+      info[i].status = SPA_RESULT_NO_FORMAT;
+      have_error = true;
+      continue;
+    }
 
-    if (info[i].buffer_id != SPA_ID_INVALID) {
-      if (!this->have_format) {
-        info[i].status = SPA_RESULT_NO_FORMAT;
-        have_error = true;
-        continue;
-      }
+    if (info[i].buffer_id >= this->n_buffers) {
+      info[i].status = SPA_RESULT_INVALID_BUFFER_ID;
+      have_error = true;
+      continue;
+    }
 
-      if (this->ready.length != 0) {
-        info[i].status = SPA_RESULT_HAVE_ENOUGH_INPUT;
-        have_enough = true;
-        continue;
-      }
-      SPA_QUEUE_PUSH_TAIL (&this->ready, SpaALSABuffer, next, &this->buffers[info[i].buffer_id]);
+    b = &this->buffers[info[i].buffer_id];
+    if (!b->outstanding) {
+      info[i].status = SPA_RESULT_INVALID_BUFFER_ID;
+      have_error = true;
+      continue;
     }
+    b->outstanding = false;
+    b->next = NULL;
+    SPA_QUEUE_PUSH_TAIL (&this->ready, SpaALSABuffer, next, b);
     info[i].status = SPA_RESULT_OK;
   }
   if (have_error)
     return SPA_RESULT_ERROR;
-  if (have_enough)
-    return SPA_RESULT_HAVE_ENOUGH_INPUT;
 
   return SPA_RESULT_OK;
 }
@@ -535,7 +670,37 @@ spa_alsa_sink_node_port_send_command (SpaNode          *node,
                                       uint32_t          port_id,
                                       SpaNodeCommand   *command)
 {
-  return SPA_RESULT_NOT_IMPLEMENTED;
+  SpaALSASink *this;
+  SpaResult res;
+
+  if (node == NULL)
+    return SPA_RESULT_INVALID_ARGUMENTS;
+
+  this = SPA_CONTAINER_OF (node, SpaALSASink, node);
+
+  if (port_id != 0)
+    return SPA_RESULT_INVALID_PORT;
+
+  switch (command->type) {
+    case SPA_NODE_COMMAND_PAUSE:
+    {
+      if (SPA_RESULT_IS_OK (res = spa_alsa_pause (this, false))) {
+        update_state (this, SPA_NODE_STATE_PAUSED);
+      }
+      break;
+    }
+    case SPA_NODE_COMMAND_START:
+    {
+      if (SPA_RESULT_IS_OK (res = spa_alsa_start (this, false))) {
+        update_state (this, SPA_NODE_STATE_STREAMING);
+      }
+      break;
+    }
+    default:
+      res = SPA_RESULT_NOT_IMPLEMENTED;
+      break;
+  }
+  return res;
 }
 
 
@@ -615,6 +780,10 @@ alsa_sink_init (const SpaHandleFactory  *factory,
       this->map = support[i].data;
     else if (strcmp (support[i].uri, SPA_LOG_URI) == 0)
       this->log = support[i].data;
+    else if (strcmp (support[i].uri, SPA_POLL__DataLoop) == 0)
+      this->data_loop = support[i].data;
+    else if (strcmp (support[i].uri, SPA_POLL__MainLoop) == 0)
+      this->main_loop = support[i].data;
   }
   if (this->map == NULL) {
     spa_log_error (this->log, "an id-map is needed");
@@ -628,7 +797,14 @@ alsa_sink_init (const SpaHandleFactory  *factory,
   this->stream = SND_PCM_STREAM_PLAYBACK;
   reset_alsa_sink_props (&this->props[1]);
 
-  this->status.flags = SPA_PORT_STATUS_FLAG_NEED_INPUT;
+  this->status.flags = SPA_PORT_STATUS_FLAG_NONE;
+
+  for (i = 0; info && i < info->n_items; i++) {
+    if (!strcmp (info->items[i].key, "alsa.card")) {
+      snprintf (this->props[1].device, 63, "hw:%s", info->items[i].value);
+      this->props[1].props.unset_mask &= ~1;
+    }
+  }
 
   update_state (this, SPA_NODE_STATE_CONFIGURE);
 
diff --git a/spa/plugins/alsa/alsa-source.c b/spa/plugins/alsa/alsa-source.c
index 7fdc025b..c37213f6 100644
--- a/spa/plugins/alsa/alsa-source.c
+++ b/spa/plugins/alsa/alsa-source.c
@@ -38,8 +38,8 @@ update_state (SpaALSASource *this, SpaNodeState state)
 }
 
 static const char default_device[] = "hw:0";
-static const uint32_t default_buffer_time = 1000;
-static const uint32_t default_period_time = 100;
+static const uint32_t default_buffer_time = 10000;
+static const uint32_t default_period_time = 1000;
 static const bool default_period_event = 0;
 
 static void
@@ -178,7 +178,7 @@ do_start (SpaPoll        *poll,
   SpaResult res;
   SpaNodeEventAsyncComplete ac;
 
-  if (SPA_RESULT_IS_OK (res = spa_alsa_start (this))) {
+  if (SPA_RESULT_IS_OK (res = spa_alsa_start (this, false))) {
     update_state (this, SPA_NODE_STATE_STREAMING);
   }
 
@@ -209,7 +209,7 @@ do_pause (SpaPoll        *poll,
   SpaResult res;
   SpaNodeEventAsyncComplete ac;
 
-  if (SPA_RESULT_IS_OK (res = spa_alsa_pause (this))) {
+  if (SPA_RESULT_IS_OK (res = spa_alsa_pause (this, false))) {
     update_state (this, SPA_NODE_STATE_PAUSED);
   }
 
@@ -441,7 +441,7 @@ spa_alsa_source_node_port_set_format (SpaNode            *node,
     return SPA_RESULT_INVALID_PORT;
 
   if (format == NULL) {
-    spa_alsa_pause (this);
+    spa_alsa_pause (this, false);
     spa_alsa_clear_buffers (this);
     spa_alsa_close (this);
     this->have_format = false;
@@ -697,6 +697,7 @@ spa_alsa_source_node_port_pull_output (SpaNode           *node,
 
     info[i].buffer_id = b->outbuf->id;
     info[i].status = SPA_RESULT_OK;
+    spa_log_debug (this->log, "pull buffer %u\n", b->outbuf->id);
   }
   if (have_error)
     return SPA_RESULT_ERROR;
@@ -726,6 +727,7 @@ spa_alsa_source_node_port_reuse_buffer (SpaNode         *node,
   if (buffer_id >= this->n_buffers)
     return SPA_RESULT_INVALID_BUFFER_ID;
 
+  spa_log_debug (this->log, "recycle buffer %u\n", buffer_id);
   recycle_buffer (this, buffer_id);
 
   return SPA_RESULT_OK;
@@ -737,7 +739,37 @@ spa_alsa_source_node_port_send_command (SpaNode          *node,
                                         uint32_t          port_id,
                                         SpaNodeCommand   *command)
 {
-  return SPA_RESULT_NOT_IMPLEMENTED;
+  SpaALSASource *this;
+  SpaResult res;
+
+  if (node == NULL)
+    return SPA_RESULT_INVALID_ARGUMENTS;
+
+  this = SPA_CONTAINER_OF (node, SpaALSASource, node);
+
+  if (port_id != 0)
+    return SPA_RESULT_INVALID_PORT;
+
+  switch (command->type) {
+    case SPA_NODE_COMMAND_PAUSE:
+    {
+      if (SPA_RESULT_IS_OK (res = spa_alsa_pause (this, false))) {
+        update_state (this, SPA_NODE_STATE_PAUSED);
+      }
+      break;
+    }
+    case SPA_NODE_COMMAND_START:
+    {
+      if (SPA_RESULT_IS_OK (res = spa_alsa_start (this, false))) {
+        update_state (this, SPA_NODE_STATE_STREAMING);
+      }
+      break;
+    }
+    default:
+      res = SPA_RESULT_NOT_IMPLEMENTED;
+      break;
+  }
+  return res;
 }
 
 static const SpaNode alsasource_node = {
diff --git a/spa/plugins/alsa/alsa-utils.c b/spa/plugins/alsa/alsa-utils.c
index 1f3446e3..d89c2584 100644
--- a/spa/plugins/alsa/alsa-utils.c
+++ b/spa/plugins/alsa/alsa-utils.c
@@ -33,18 +33,11 @@ spa_alsa_open (SpaALSAState *state)
                        SND_PCM_NO_AUTO_CHANNELS |
                        SND_PCM_NO_AUTO_FORMAT), "open failed");
 
-  if ((state->poll.n_fds = snd_pcm_poll_descriptors_count (state->hndl)) <= 0) {
-    spa_log_error (state->log, "Invalid poll descriptors count %d\n", state->poll.n_fds);
-    return SPA_RESULT_ERROR;
-  }
-  if ((err = snd_pcm_poll_descriptors (state->hndl, (struct pollfd *)state->fds, state->poll.n_fds)) < 0) {
-    spa_log_error (state->log, "Unable to obtain poll descriptors for playback: %s\n", snd_strerror(err));
-    return SPA_RESULT_ERROR;
-  }
 
   state->poll.id = 0;
   state->poll.enabled = false;
   state->poll.fds = state->fds;
+  state->poll.n_fds = 0;
   state->poll.idle_cb = NULL;
   state->poll.before_cb = NULL;
   state->poll.after_cb = alsa_on_fd_events;
@@ -242,33 +235,31 @@ set_swparams (SpaALSAState *state)
 static int
 xrun_recovery (SpaALSAState *state, snd_pcm_t *hndl, int err)
 {
-  if (err == -EPIPE) {	/* under-run */
-    err = snd_pcm_prepare(hndl);
-    if (err < 0)
-      spa_log_error (state->log, "Can't recovery from underrun, prepare failed: %s\n", snd_strerror(err));
-    return 0;
-  } else if (err == -ESTRPIPE) {
-    while ((err = snd_pcm_resume(hndl)) == -EAGAIN)
-      sleep(1);	/* wait until the suspend flag is released */
-    if (err < 0) {
-      err = snd_pcm_prepare(hndl);
-      if (err < 0)
-        spa_log_error (state->log, "Can't recovery from suspend, prepare failed: %s\n", snd_strerror(err));
+  snd_pcm_status_t *status;
+
+  snd_pcm_status_alloca (&status);
+
+  if ((err = snd_pcm_status (hndl, status)) < 0) {
+    spa_log_error (state->log, "snd_pcm_status error: %s\n", snd_strerror (err));
+  }
+
+  if (snd_pcm_status_get_state (status) == SND_PCM_STATE_SUSPENDED) {
+    spa_log_info (state->log, "SUSPENDED, trying to resume\n");
+
+    if ((err = snd_pcm_prepare (hndl)) < 0) {
+      spa_log_error (state->log, "snd_pcm_prepare error: %s\n", snd_strerror (err));
     }
-    return 0;
   }
-  return err;
-}
+  if (snd_pcm_status_get_state (status) == SND_PCM_STATE_XRUN) {
+    spa_log_info (state->log, "XRUN\n");
+  }
 
-static void
-pull_input (SpaALSAState *state, void *data, snd_pcm_uframes_t frames)
-{
-  SpaNodeEventNeedInput ni;
+  if (spa_alsa_pause (state, true) != SPA_RESULT_OK)
+    return -1;
+  if (spa_alsa_start (state, true) != SPA_RESULT_OK)
+    return -1;
 
-  ni.event.type = SPA_NODE_EVENT_TYPE_NEED_INPUT;
-  ni.event.size = sizeof (ni);
-  ni.port_id = 0;
-  state->event_cb (&state->node, &ni.event, state->user_data);
+  return err;
 }
 
 static int
@@ -276,37 +267,73 @@ mmap_write (SpaALSAState *state)
 {
   snd_pcm_t *hndl = state->hndl;
   int err;
-  snd_pcm_sframes_t avail, commitres;
+  snd_pcm_sframes_t avail;
   snd_pcm_uframes_t offset, frames, size;
   const snd_pcm_channel_area_t *my_areas;
+  SpaNodeEventNeedInput ni;
+  SpaALSABuffer *b;
+  snd_pcm_status_t *status;
 
-  if ((avail = snd_pcm_avail_update (hndl)) < 0) {
-    if ((err = xrun_recovery (state, hndl, avail)) < 0) {
-      spa_log_error (state->log, "Write error: %s\n", snd_strerror (err));
-      return -1;
-    }
+  snd_pcm_status_alloca (&status);
+
+  if ((err = snd_pcm_status (hndl, status)) < 0) {
+    spa_log_error (state->log, "snd_pcm_status error: %s\n", snd_strerror (err));
+    return -1;
   }
 
+  avail = snd_pcm_status_get_avail (status);
+
   size = avail;
   while (size > 0) {
     frames = size;
     if ((err = snd_pcm_mmap_begin (hndl, &my_areas, &offset, &frames)) < 0) {
-      if ((err = xrun_recovery (state, hndl, err)) < 0) {
-        spa_log_error (state->log, "MMAP begin avail error: %s\n", snd_strerror(err));
-        return -1;
-      }
+      spa_log_error (state->log, "snd_pcm_mmap_begin error: %s\n", snd_strerror(err));
+      return -1;
     }
 
-    pull_input (state,
-                (uint8_t *)my_areas[0].addr + (offset * sizeof (uint16_t) * 2),
-                frames);
+    ni.event.type = SPA_NODE_EVENT_TYPE_NEED_INPUT;
+    ni.event.size = sizeof (ni);
+    ni.port_id = 0;
+    state->event_cb (&state->node, &ni.event, state->user_data);
 
-    commitres = snd_pcm_mmap_commit (hndl, offset, frames);
-    if (commitres < 0 || (snd_pcm_uframes_t)commitres != frames) {
-      if ((err = xrun_recovery (state, hndl, commitres >= 0 ? -EPIPE : commitres)) < 0) {
-        spa_log_error (state->log, "MMAP commit error: %s\n", snd_strerror(err));
-        return -1;
+    SPA_QUEUE_PEEK_HEAD (&state->ready, SpaALSABuffer, b);
+
+    if (b) {
+      uint8_t *src;
+      size_t n_bytes;
+
+      src = SPA_MEMBER (b->outbuf->datas[0].data, b->outbuf->datas[0].offset + state->ready_offset, void);
+      n_bytes = SPA_MIN (b->outbuf->datas[0].size - state->ready_offset, frames * state->frame_size);
+      frames = SPA_MIN (frames, n_bytes / state->frame_size);
+
+      memcpy ((uint8_t *)my_areas[0].addr + (offset * state->frame_size),
+              src,
+              n_bytes);
+
+      state->ready_offset += n_bytes;
+      if (state->ready_offset >= b->outbuf->datas[0].size) {
+        SpaNodeEventReuseBuffer rb;
+
+        SPA_QUEUE_POP_HEAD (&state->ready, SpaALSABuffer, next, b);
+        b->outstanding = true;
+
+        rb.event.type = SPA_NODE_EVENT_TYPE_REUSE_BUFFER;
+        rb.event.size = sizeof (rb);
+        rb.port_id = 0;
+        rb.buffer_id = b->outbuf->id;
+        state->event_cb (&state->node, &rb.event, state->user_data);
+
+        state->ready_offset = 0;
       }
+    } else {
+      spa_log_warn (state->log, "underrun\n");
+      snd_pcm_areas_silence (my_areas, offset, state->channels, frames, state->format);
+    }
+
+    if ((err = snd_pcm_mmap_commit (hndl, offset, frames)) < 0) {
+      spa_log_error (state->log, "snd_pcm_mmap_commit error: %s\n", snd_strerror(err));
+      if (err != -EPIPE && err != -ESTRPIPE)
+        return -1;
     }
     size -= frames;
   }
@@ -318,7 +345,7 @@ mmap_read (SpaALSAState *state)
 {
   snd_pcm_t *hndl = state->hndl;
   int err;
-  snd_pcm_sframes_t avail, commitres;
+  snd_pcm_sframes_t avail;
   snd_pcm_uframes_t offset, frames, size;
   snd_pcm_status_t *status;
   const snd_pcm_channel_area_t *my_areas;
@@ -330,8 +357,10 @@ mmap_read (SpaALSAState *state)
 
   snd_pcm_status_alloca(&status);
 
-  if ((err = snd_pcm_status (hndl, status)) < 0)
+  if ((err = snd_pcm_status (hndl, status)) < 0) {
+    spa_log_error (state->log, "snd_pcm_status error: %s\n", snd_strerror(err));
     return err;
+  }
 
   avail = snd_pcm_status_get_avail (status);
   snd_pcm_status_get_htstamp (status, &htstamp);
@@ -361,10 +390,8 @@ mmap_read (SpaALSAState *state)
   while (size > 0) {
     frames = size;
     if ((err = snd_pcm_mmap_begin (hndl, &my_areas, &offset, &frames)) < 0) {
-      if ((err = xrun_recovery (state, hndl, err)) < 0) {
-        spa_log_error (state->log, "MMAP begin avail error: %s\n", snd_strerror (err));
-        return -1;
-      }
+      spa_log_error (state->log, "snd_pcm_mmap_begin error: %s\n", snd_strerror (err));
+      return -1;
     }
 
     if (b) {
@@ -374,16 +401,11 @@ mmap_read (SpaALSAState *state)
               (uint8_t *)my_areas[0].addr + (offset * state->frame_size),
               n_bytes);
       dest += n_bytes;
-    } else {
-      snd_pcm_areas_silence (my_areas, offset, state->channels, frames, state->format);
     }
 
-    commitres = snd_pcm_mmap_commit (hndl, offset, frames);
-    if (commitres < 0 || (snd_pcm_uframes_t)commitres != frames) {
-      if ((err = xrun_recovery (state, hndl, commitres >= 0 ? -EPIPE : commitres)) < 0) {
-        spa_log_error (state->log, "MMAP commit error: %s\n", snd_strerror(err));
-        return -1;
-      }
+    if ((err = snd_pcm_mmap_commit (hndl, offset, frames)) < 0) {
+      spa_log_error (state->log, "snd_pcm_mmap_commit error: %s\n", snd_strerror(err));
+      return -1;
     }
     size -= frames;
   }
@@ -413,34 +435,27 @@ alsa_on_fd_events (SpaPollNotifyData *data)
   SpaALSAState *state = data->user_data;
   snd_pcm_t *hndl = state->hndl;
   int err;
-  unsigned short revents;
+  unsigned short revents = 0;
 
   snd_pcm_poll_descriptors_revents (hndl,
                                     (struct pollfd *)data->fds,
                                     data->n_fds,
                                     &revents);
   if (revents & POLLERR) {
-    if (snd_pcm_state (hndl) == SND_PCM_STATE_XRUN ||
-        snd_pcm_state (hndl) == SND_PCM_STATE_SUSPENDED) {
-      err = snd_pcm_state (hndl) == SND_PCM_STATE_XRUN ? -EPIPE : -ESTRPIPE;
-      if ((err = xrun_recovery (state, hndl, err)) < 0) {
-        spa_log_error (state->log, "error: %s\n", snd_strerror (err));
-        return -1;
-      }
-    } else {
-      spa_log_error (state->log, "Wait for poll failed\n");
+    if ((err = xrun_recovery (state, hndl, err)) < 0) {
+      spa_log_error (state->log, "error: %s\n", snd_strerror (err));
       return -1;
     }
   }
 
   if (state->stream == SND_PCM_STREAM_CAPTURE) {
     if (!(revents & POLLIN))
-      return -1;
+      return 0;
 
     mmap_read (state);
   } else {
     if (!(revents & POLLOUT))
-      return -1;
+      return 0;
 
     mmap_write (state);
   }
@@ -449,7 +464,7 @@ alsa_on_fd_events (SpaPollNotifyData *data)
 }
 
 SpaResult
-spa_alsa_start (SpaALSAState *state)
+spa_alsa_start (SpaALSAState *state, bool xrun_recover)
 {
   int err;
 
@@ -457,31 +472,58 @@ spa_alsa_start (SpaALSAState *state)
     return SPA_RESULT_OK;
 
   CHECK (set_swparams (state), "swparams");
-  snd_pcm_dump (state->hndl, state->output);
+  if (!xrun_recover)
+    snd_pcm_dump (state->hndl, state->output);
+
+  if ((err = snd_pcm_prepare (state->hndl)) < 0) {
+    spa_log_error (state->log, "snd_pcm_prepare error: %s\n", snd_strerror (err));
+    return SPA_RESULT_ERROR;
+  }
+
+  if ((state->poll.n_fds = snd_pcm_poll_descriptors_count (state->hndl)) <= 0) {
+    spa_log_error (state->log, "Invalid poll descriptors count %d\n", state->poll.n_fds);
+    return SPA_RESULT_ERROR;
+  }
+  if ((err = snd_pcm_poll_descriptors (state->hndl, (struct pollfd *)state->fds, state->poll.n_fds)) < 0) {
+    spa_log_error (state->log, "snd_pcm_poll_descriptors: %s\n", snd_strerror(err));
+    return SPA_RESULT_ERROR;
+  }
+
+  if (!xrun_recover) {
+    state->poll.enabled = true;
+    spa_poll_update_item (state->data_loop, &state->poll);
+  }
 
   if (state->stream == SND_PCM_STREAM_PLAYBACK) {
     mmap_write (state);
   }
 
-  state->poll.enabled = true;
-  spa_poll_update_item (state->data_loop, &state->poll);
+  if ((err = snd_pcm_start (state->hndl)) < 0) {
+    spa_log_error (state->log, "snd_pcm_start: %s\n", snd_strerror (err));
+    return SPA_RESULT_ERROR;
+  }
 
-  err = snd_pcm_start (state->hndl);
   state->started = true;
 
   return SPA_RESULT_OK;
 }
 
 SpaResult
-spa_alsa_pause (SpaALSAState *state)
+spa_alsa_pause (SpaALSAState *state, bool xrun_recover)
 {
+  int err;
+
   if (!state->started)
     return SPA_RESULT_OK;
 
-  state->poll.enabled = false;
-  spa_poll_update_item (state->data_loop, &state->poll);
+  if (!xrun_recover) {
+    state->poll.enabled = false;
+    spa_poll_update_item (state->data_loop, &state->poll);
+  }
+
+  if ((err = snd_pcm_drop (state->hndl)) < 0)
+    spa_log_error (state->log, "snd_pcm_drop %s\n", snd_strerror (err));
 
-  snd_pcm_drop (state->hndl);
   state->started = false;
 
   return SPA_RESULT_OK;
diff --git a/spa/plugins/alsa/alsa-utils.h b/spa/plugins/alsa/alsa-utils.h
index 26d0a9bd..da920e72 100644
--- a/spa/plugins/alsa/alsa-utils.h
+++ b/spa/plugins/alsa/alsa-utils.h
@@ -47,7 +47,7 @@ typedef struct {
   bool period_event;
 } SpaALSAProps;
 
-#define MAX_BUFFERS 16
+#define MAX_BUFFERS 64
 
 struct _SpaALSABuffer {
   SpaBuffer *outbuf;
@@ -106,6 +106,7 @@ struct _SpaALSAState {
 
   SpaQueue free;
   SpaQueue ready;
+  size_t ready_offset;
 
   bool started;
   SpaPollFd fds[16];
@@ -120,8 +121,8 @@ int spa_alsa_set_format (SpaALSAState *state,
                          SpaFormatAudio *fmt,
                          SpaPortFormatFlags flags);
 
-SpaResult spa_alsa_start (SpaALSAState *state);
-SpaResult spa_alsa_pause (SpaALSAState *state);
+SpaResult spa_alsa_start (SpaALSAState *state, bool xrun_recover);
+SpaResult spa_alsa_pause (SpaALSAState *state, bool xrun_recover);
 SpaResult spa_alsa_close (SpaALSAState *state);
 
 #ifdef __cplusplus
diff --git a/spa/plugins/v4l2/v4l2-source.c b/spa/plugins/v4l2/v4l2-source.c
index ec503cbf..2ecd11b1 100644
--- a/spa/plugins/v4l2/v4l2-source.c
+++ b/spa/plugins/v4l2/v4l2-source.c
@@ -150,6 +150,7 @@ struct _SpaV4l2Source {
 static void
 update_state (SpaV4l2Source *this, SpaNodeState state)
 {
+  spa_log_info (this->log, "state: %d\n", state);
   this->node.state = state;
 }
 #include "v4l2-utils.c"
@@ -225,7 +226,7 @@ spa_v4l2_source_node_set_props (SpaNode         *node,
 }
 
 static SpaResult
-do_send_event (SpaPoll        *poll,
+do_pause_done (SpaPoll        *poll,
                bool            async,
                uint32_t        seq,
                size_t          size,
@@ -233,14 +234,24 @@ do_send_event (SpaPoll        *poll,
                void           *user_data)
 {
   SpaV4l2Source *this = user_data;
+  SpaV4l2State *state = &this->state[0];
+  SpaNodeEventAsyncComplete *ac = data;
 
-  this->event_cb (&this->node, data, this->user_data);
+
+  if (SPA_RESULT_IS_OK (ac->res))
+    ac->res = spa_v4l2_stream_off (this);
+
+  if (SPA_RESULT_IS_OK (ac->res)) {
+    state->started = false;
+    update_state (this, SPA_NODE_STATE_PAUSED);
+  }
+  this->event_cb (&this->node, &ac->event, this->user_data);
 
   return SPA_RESULT_OK;
 }
 
 static SpaResult
-do_start (SpaPoll        *poll,
+do_pause (SpaPoll        *poll,
           bool            async,
           uint32_t        seq,
           size_t          size,
@@ -250,26 +261,49 @@ do_start (SpaPoll        *poll,
   SpaV4l2Source *this = user_data;
   SpaResult res;
   SpaNodeEventAsyncComplete ac;
+  SpaNodeCommand *cmd = data;
+
+  res = spa_node_port_send_command (&this->node,
+                                    SPA_DIRECTION_OUTPUT,
+                                    0,
+                                    cmd);
+
+  ac.event.type = SPA_NODE_EVENT_TYPE_ASYNC_COMPLETE;
+  ac.event.size = sizeof (SpaNodeEventAsyncComplete);
+  ac.seq = seq;
+  ac.res = res;
+  spa_poll_invoke (this->state[0].main_loop,
+                   do_pause_done,
+                   seq,
+                   sizeof (ac),
+                   &ac,
+                   this);
+  return SPA_RESULT_OK;
+}
+
+static SpaResult
+do_start_done (SpaPoll        *poll,
+               bool            async,
+               uint32_t        seq,
+               size_t          size,
+               void           *data,
+               void           *user_data)
+{
+  SpaV4l2Source *this = user_data;
+  SpaV4l2State *state = &this->state[0];
+  SpaNodeEventAsyncComplete *ac = data;
 
-  res = spa_v4l2_start (this);
-
-  if (async) {
-    ac.event.type = SPA_NODE_EVENT_TYPE_ASYNC_COMPLETE;
-    ac.event.size = sizeof (SpaNodeEventAsyncComplete);
-    ac.seq = seq;
-    ac.res = res;
-    spa_poll_invoke (this->state[0].main_loop,
-                     do_send_event,
-                     SPA_ID_INVALID,
-                     sizeof (ac),
-                     &ac,
-                     this);
+  if (SPA_RESULT_IS_OK (ac->res)) {
+    state->started = true;
+    update_state (this, SPA_NODE_STATE_STREAMING);
   }
-  return res;
+  this->event_cb (&this->node, &ac->event, this->user_data);
+
+  return SPA_RESULT_OK;
 }
 
 static SpaResult
-do_pause (SpaPoll        *poll,
+do_start (SpaPoll        *poll,
           bool            async,
           uint32_t        seq,
           size_t          size,
@@ -279,22 +313,25 @@ do_pause (SpaPoll        *poll,
   SpaV4l2Source *this = user_data;
   SpaResult res;
   SpaNodeEventAsyncComplete ac;
+  SpaNodeCommand *cmd = data;
+
+  res = spa_node_port_send_command (&this->node,
+                                    SPA_DIRECTION_OUTPUT,
+                                    0,
+                                    cmd);
+
+  ac.event.type = SPA_NODE_EVENT_TYPE_ASYNC_COMPLETE;
+  ac.event.size = sizeof (SpaNodeEventAsyncComplete);
+  ac.seq = seq;
+  ac.res = res;
+  spa_poll_invoke (this->state[0].main_loop,
+                   do_start_done,
+                   seq,
+                   sizeof (ac),
+                   &ac,
+                   this);
 
-  res = spa_v4l2_pause (this);
-
-  if (async) {
-    ac.event.type = SPA_NODE_EVENT_TYPE_ASYNC_COMPLETE;
-    ac.event.size = sizeof (SpaNodeEventAsyncComplete);
-    ac.seq = seq;
-    ac.res = res;
-    spa_poll_invoke (this->state[0].main_loop,
-                     do_send_event,
-                     SPA_ID_INVALID,
-                     sizeof (ac),
-                     &ac,
-                     this);
-  }
-  return res;
+  return SPA_RESULT_OK;
 }
 
 static SpaResult
@@ -315,6 +352,7 @@ spa_v4l2_source_node_send_command (SpaNode        *node,
     case SPA_NODE_COMMAND_START:
     {
       SpaV4l2State *state = &this->state[0];
+      SpaResult res;
 
       if (state->current_format == NULL)
         return SPA_RESULT_NO_FORMAT;
@@ -322,11 +360,17 @@ spa_v4l2_source_node_send_command (SpaNode        *node,
       if (state->n_buffers == 0)
         return SPA_RESULT_NO_BUFFERS;
 
+      if (state->started)
+        return SPA_RESULT_OK;
+
+      if ((res = spa_v4l2_stream_on (this)) < 0)
+        return res;
+
       return spa_poll_invoke (this->state[0].data_loop,
                               do_start,
                               ++this->seq,
-                              0,
-                              NULL,
+                              command->size,
+                              command,
                               this);
     }
     case SPA_NODE_COMMAND_PAUSE:
@@ -339,13 +383,17 @@ spa_v4l2_source_node_send_command (SpaNode        *node,
       if (state->n_buffers == 0)
         return SPA_RESULT_NO_BUFFERS;
 
+      if (!state->started)
+        return SPA_RESULT_OK;
+
       return spa_poll_invoke (this->state[0].data_loop,
                               do_pause,
                               ++this->seq,
-                              0,
-                              NULL,
+                              command->size,
+                              command,
                               this);
     }
+
     case SPA_NODE_COMMAND_FLUSH:
     case SPA_NODE_COMMAND_DRAIN:
     case SPA_NODE_COMMAND_MARKER:
@@ -497,7 +545,7 @@ spa_v4l2_source_node_port_set_format (SpaNode            *node,
   state = &this->state[port_id];
 
   if (format == NULL) {
-    spa_v4l2_pause (this);
+    spa_v4l2_stream_off (this);
     spa_v4l2_clear_buffers (this);
     spa_v4l2_close (this);
     state->current_format = NULL;
@@ -797,7 +845,31 @@ spa_v4l2_source_node_port_send_command (SpaNode        *node,
                                         uint32_t        port_id,
                                         SpaNodeCommand *command)
 {
-  return SPA_RESULT_NOT_IMPLEMENTED;
+  SpaV4l2Source *this;
+  SpaResult res;
+
+  if (node == NULL)
+    return SPA_RESULT_INVALID_ARGUMENTS;
+
+  this = SPA_CONTAINER_OF (node, SpaV4l2Source, node);
+
+  if (port_id != 0)
+    return SPA_RESULT_INVALID_PORT;
+
+  switch (command->type) {
+    case SPA_NODE_COMMAND_PAUSE:
+      res = spa_v4l2_port_set_enabled (this, false);
+      break;
+
+    case SPA_NODE_COMMAND_START:
+      res = spa_v4l2_port_set_enabled (this, true);
+      break;
+
+    default:
+      res = SPA_RESULT_NOT_IMPLEMENTED;
+      break;
+  }
+  return res;
 }
 
 static const SpaNode v4l2source_node = {
diff --git a/spa/plugins/v4l2/v4l2-utils.c b/spa/plugins/v4l2/v4l2-utils.c
index 7ff9f043..55f4edf6 100644
--- a/spa/plugins/v4l2/v4l2-utils.c
+++ b/spa/plugins/v4l2/v4l2-utils.c
@@ -1134,46 +1134,38 @@ spa_v4l2_alloc_buffers (SpaV4l2Source   *this,
 }
 
 static SpaResult
-spa_v4l2_start (SpaV4l2Source *this)
+spa_v4l2_stream_on (SpaV4l2Source *this)
 {
   SpaV4l2State *state = &this->state[0];
   enum v4l2_buf_type type;
 
-  if (state->started)
-    return SPA_RESULT_OK;
-
   type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
   if (xioctl (state->fd, VIDIOC_STREAMON, &type) < 0) {
-    perror ("VIDIOC_STREAMON");
+    spa_log_error (this->log, "VIDIOC_STREAMON: %s", strerror (errno));
     return SPA_RESULT_ERROR;
   }
-  state->started = true;
-  update_state (this, SPA_NODE_STATE_STREAMING);
+  return SPA_RESULT_OK;
+}
 
-  state->poll.enabled = true;
+static SpaResult
+spa_v4l2_port_set_enabled (SpaV4l2Source *this, bool enabled)
+{
+  SpaV4l2State *state = &this->state[0];
+  state->poll.enabled = enabled;
   spa_poll_update_item (state->data_loop, &state->poll);
-
   return SPA_RESULT_OK;
 }
 
 static SpaResult
-spa_v4l2_pause (SpaV4l2Source *this)
+spa_v4l2_stream_off (SpaV4l2Source *this)
 {
   SpaV4l2State *state = &this->state[0];
   enum v4l2_buf_type type;
   int i;
 
-  if (!state->started)
-    return SPA_RESULT_OK;
-
-  state->started = false;
-
-  state->poll.enabled = false;
-  spa_poll_update_item (state->data_loop, &state->poll);
-
   type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
   if (xioctl (state->fd, VIDIOC_STREAMOFF, &type) < 0) {
-    perror ("VIDIOC_STREAMOFF");
+    spa_log_error (this->log, "VIDIOC_STREAMOFF: %s", strerror (errno));
     return SPA_RESULT_ERROR;
   }
   for (i = 0; i < state->n_buffers; i++) {
@@ -1182,9 +1174,8 @@ spa_v4l2_pause (SpaV4l2Source *this)
     b = &state->buffers[i];
     if (!b->outstanding)
       if (xioctl (state->fd, VIDIOC_QBUF, &b->v4l2_buffer) < 0)
-        perror ("VIDIOC_QBUF");
+        spa_log_warn (this->log, "VIDIOC_QBUF: %s", strerror (errno));
   }
-  update_state (this, SPA_NODE_STATE_PAUSED);
 
   return SPA_RESULT_OK;
 }