Optimize Delaylines: block-process (not one sample at a time)

This also tweaks fade behavior when the latency changes to prefer a
x-fade when possible.

This new variant does not support concurrent re-allocation and
execution. Hence the auto-connect thread needs to take a lock before
updating latencies (actually there's no need for an explicit update with
built-in backends, so this case remains to be updated further)

1 files changed, 1 insertions, 0 deletions

diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index ef08eb0bf2..dabd4bc187 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -7353,6 +7353,7 @@ Session::auto_connect_thread_run ()
 			 * modifies the capture-offset, which can be a problem.
 			 */
 			while (g_atomic_int_and (&_latency_recompute_pending, 0)) {
+				Glib::Threads::Mutex::Lock lm (AudioEngine::instance()->process_lock ());
 				update_latency_compensation ();
 			}
 		}