use dedicated buffers for route (and track)

"scratch buffers are by definition scratch and their contents are undefined at all times"
"silent buffers are by definition all-zero and should not be used for real data"

But track & route were using those for actual data; plugins (which may run
in the same thread and may get the same buffers) use them for scratch thereby
overwriting real data.

In particular get_silent_buffers() (used by LadspaPlugin::connect_and_run)
clears the buffer which can holds real data:
e.g. via  Route::passthru_silence() -> plugin1 -> plugin2 (clears output of plugin1)

1 files changed, 7 insertions, 0 deletions

diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index 914c6a9a77..ccc694f878 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -4176,6 +4176,13 @@ Session::get_scratch_buffers (ChanCount count)
 }
 
 BufferSet&
+Session::get_route_buffers (ChanCount count, bool silence)
+{
+	return ProcessThread::get_route_buffers (count, silence);
+}
+
+
+BufferSet&
 Session::get_mix_buffers (ChanCount count)
 {
 	return ProcessThread::get_mix_buffers (count);