fixed strange ALSA-sequencer behaviour when using MIDI-controllers and controlling intrument-tracks via MIDI (closes #2062907)

git-svn-id: https://lmms.svn.sf.net/svnroot/lmms/trunk/lmms@1464 0778d3d1-df1d-0410-868b-ea421aaaa00d

src/core/midi/midi_alsa_seq.cpp

@@ -428,6 +428,10 @@ void midiALSASeq::run( void )
 		{
 			break;
 		}
+
+		do	// while event queue is not empty
+		{
+
 		snd_seq_event_t * ev;
 		snd_seq_event_input( m_seqHandle, &ev );
 
@@ -521,6 +525,8 @@ void midiALSASeq::run( void )
 				break;
 		}
 
+		} while( snd_seq_event_input_pending( m_seqHandle, 0 ) > 0 );
+
 	}
 
 	delete[] pollfd_set;