A new patch for fixing the alsa restart issue. Submitted by Volker Schroer.

[debian/gnuradio] / gr-audio-alsa / src / audio_alsa_sink.cc

diff --git a/gr-audio-alsa/src/audio_alsa_sink.cc b/gr-audio-alsa/src/audio_alsa_sink.cc
index 84bf49151af4d8f1a9ceb3ded9c6b64c8d544e35..d44a93b3f37a44ccfb3635eeadf3419f6a8b9892 100644 (file)
--- a/gr-audio-alsa/src/audio_alsa_sink.cc
+++ b/gr-audio-alsa/src/audio_alsa_sink.cc
@@ -90,8 +90,7 @@ audio_alsa_sink::audio_alsa_sink (int sampling_rate,
     d_period_size (0),
     d_buffer_size_bytes (0), d_buffer (0),
     d_worker (0), d_special_case_mono_to_stereo (false),
-    d_nunderuns (0), d_nsuspends (0), d_ok_to_block(ok_to_block),
-    d_change_in_progress(false)
+    d_nunderuns (0), d_nsuspends (0), d_ok_to_block(ok_to_block)
 {
   CHATTY_DEBUG = gr_prefs::singleton()->get_bool("audio_alsa", "verbose", false);
 
@@ -222,13 +221,14 @@ audio_alsa_sink::check_topology (int ninputs, int noutputs)
   int nchan = ninputs;
   int err;
 
-  // FIXME check_topology may be called more than once.
+  // Check the state of the stream
   // Ensure that the pcm is in a state where we can still mess with the hw_params
-
-  d_change_in_progress = true;
-  
-  if (snd_pcm_state (d_pcm_handle) == SND_PCM_STATE_RUNNING)
-    snd_pcm_drop (d_pcm_handle);
+  snd_pcm_state_t state;
+  state=snd_pcm_state(d_pcm_handle);
+  if ( state== SND_PCM_STATE_RUNNING)
+    return true;  // If stream is running, don't change any parameters
+  else if(state == SND_PCM_STATE_XRUN )
+    snd_pcm_prepare ( d_pcm_handle ); // Prepare stream on underrun, and we can set parameters;
   
   bool special_case = nchan == 1 && d_special_case_mono_to_stereo;
   if (special_case)
@@ -238,7 +238,6 @@ audio_alsa_sink::check_topology (int ninputs, int noutputs)
 
   if (err < 0){
     output_error_msg ("set_channels failed", err);
-    d_change_in_progress = false;
     return false;
   }
 
@@ -246,7 +245,6 @@ audio_alsa_sink::check_topology (int ninputs, int noutputs)
   err = snd_pcm_hw_params(d_pcm_handle, d_hw_params);
   if (err < 0){
     output_error_msg ("snd_pcm_hw_params failed", err);
-    d_change_in_progress = false;
     return false;
   }
 
@@ -297,7 +295,6 @@ audio_alsa_sink::check_topology (int ninputs, int noutputs)
   default:
     assert (0);
   }
-  d_change_in_progress = false;
   return true;
 }
 
@@ -496,13 +493,6 @@ audio_alsa_sink::write_buffer (const void *vbuffer,
 {
   const unsigned char *buffer = (const unsigned char *) vbuffer;
 
-  int change_counter = 10;
-  while (d_change_in_progress == true && change_counter >= 0) {
-    change_counter--;
-    usleep(10000);
-  }
-  d_change_in_progress = false;
-       
   while (nframes > 0){
     int r = snd_pcm_writei (d_pcm_handle, buffer, nframes);
     if (r == -EAGAIN)