alsa: Ignore errors when unpreparing or closing the device

Errors could happen here when the device was removed already
or when something is broken anyway. If errors happen here and
they're propagated, the element can't shutdown cleanly.

Fixes bug #614545.

ext/alsa/gstalsasink.c

@@ -764,52 +764,27 @@ static gboolean
 gst_alsasink_unprepare (GstAudioSink * asink)
 {
   GstAlsaSink *alsa;
-  gint err;
 
   alsa = GST_ALSA_SINK (asink);
 
-  CHECK (snd_pcm_drop (alsa->handle), drop);
-
-  CHECK (snd_pcm_hw_free (alsa->handle), hw_free);
+  snd_pcm_drop (alsa->handle);
+  snd_pcm_hw_free (alsa->handle);
 
   return TRUE;
-
-  /* ERRORS */
-drop:
-  {
-    GST_ELEMENT_ERROR (alsa, RESOURCE, SETTINGS, (NULL),
-        ("Could not drop samples: %s", snd_strerror (err)));
-    return FALSE;
-  }
-hw_free:
-  {
-    GST_ELEMENT_ERROR (alsa, RESOURCE, SETTINGS, (NULL),
-        ("Could not free hw params: %s", snd_strerror (err)));
-    return FALSE;
-  }
 }
 
 static gboolean
 gst_alsasink_close (GstAudioSink * asink)
 {
   GstAlsaSink *alsa = GST_ALSA_SINK (asink);
-  gint err;
 
   if (alsa->handle) {
-    CHECK (snd_pcm_close (alsa->handle), close_error);
+    snd_pcm_close (alsa->handle);
     alsa->handle = NULL;
   }
   gst_caps_replace (&alsa->cached_caps, NULL);
 
   return TRUE;
-
-  /* ERRORS */
-close_error:
-  {
-    GST_ELEMENT_ERROR (alsa, RESOURCE, CLOSE, (NULL),
-        ("Playback close error: %s", snd_strerror (err)));
-    return FALSE;
-  }
 }
 
 

ext/alsa/gstalsasrc.c

@@ -693,37 +693,14 @@ static gboolean
 gst_alsasrc_unprepare (GstAudioSrc * asrc)
 {
   GstAlsaSrc *alsa;
-  gint err;
 
   alsa = GST_ALSA_SRC (asrc);
 
-  CHECK (snd_pcm_drop (alsa->handle), drop);
-
-  CHECK (snd_pcm_hw_free (alsa->handle), hw_free);
-
-  CHECK (snd_pcm_nonblock (alsa->handle, 1), non_block);
+  snd_pcm_drop (alsa->handle);
+  snd_pcm_hw_free (alsa->handle);
+  snd_pcm_nonblock (alsa->handle, 1);
 
   return TRUE;
-
-  /* ERRORS */
-drop:
-  {
-    GST_ELEMENT_ERROR (alsa, RESOURCE, SETTINGS, (NULL),
-        ("Could not drop samples: %s", snd_strerror (err)));
-    return FALSE;
-  }
-hw_free:
-  {
-    GST_ELEMENT_ERROR (alsa, RESOURCE, SETTINGS, (NULL),
-        ("Could not free hw params: %s", snd_strerror (err)));
-    return FALSE;
-  }
-non_block:
-  {
-    GST_ELEMENT_ERROR (alsa, RESOURCE, SETTINGS, (NULL),
-        ("Could not set device to nonblocking: %s", snd_strerror (err)));
-    return FALSE;
-  }
 }
 
 static gboolean