Fix issues with the queue locking up when there is no signal.

diff --git a/bmusb b/bmusb
index f38bf2bef09e52ba1e15678f5688132f282b50c2..6fd0f2d883caf80001dc04e324ac4036ae396e06 160000 (submodule)
--- a/bmusb
+++ b/bmusb
@@ -1 +1 @@
-Subproject commit f38bf2bef09e52ba1e15678f5688132f282b50c2
+Subproject commit 6fd0f2d883caf80001dc04e324ac4036ae396e06