enqueue-midi-bytes: Actually enqueue, rather than waiting for empty queue

This avoids a deadlock if the midi readout isn't happening for some
reason.

1 files changed, 7 insertions, 3 deletions

diff --git a/guile/starlet/midi-control/base.scm b/guile/starlet/midi-control/base.scm
index bcbb741..9585766 100644
--- a/guile/starlet/midi-control/base.scm
+++ b/guile/starlet/midi-control/base.scm
@@ -96,9 +96,13 @@
 
 (define enqueue-midi-bytes!
   (lambda bytes
-    (unless (eq? (atomic-box-compare-and-swap! send-queue '() bytes)
-                 '())
-      (apply enqueue-midi-bytes! bytes))))
+    (let* ((old-queue (atomic-box-ref send-queue))
+           (new-queue (append old-queue bytes)))
+      (unless (eq? (atomic-box-compare-and-swap! send-queue
+                                                 old-queue
+                                                 new-queue)
+                   old-queue)
+        (apply enqueue-midi-bytes! bytes)))))
 
 
 (define* (send-note-on note