OBSOLETE. Fix "audio_alsa_sink[hw:0,0]: snd_pcm_hw_params failed: File descriptor in bad state".

gr-audio-alsa.diff

diff --git a/gr-audio-alsa/src/audio_alsa_sink.cc b/gr-audio-alsa/src/audio_alsa_sink.cc
index d6b7f84..38ed86b 100644
--- a/gr-audio-alsa/src/audio_alsa_sink.cc
+++ b/gr-audio-alsa/src/audio_alsa_sink.cc
@@ -219,9 +219,15 @@ 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
-
+  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)
     nchan = 2;

hi thanks for this patch
how can i apply this patch in raspbian version of gnu_companion