pipeline-graph: Set xrun flags automatically on cross-pipeline buffers

Pipelines have userspace-controlled lifecycles, so it's not possible
to guarantee buffer overrun behavior in all cases.  Fix it up
automatically.

Signed-off-by: Andy Ross <[email protected]>

src/audio/pipeline/pipeline-graph.c

@@ -191,6 +191,24 @@ int pipeline_connect(struct comp_dev *comp, struct comp_buffer *buffer,
  buffer_attach(buffer, comp_list, dir);
  buffer_set_comp(buffer, comp, dir);
 
+ /* Cross-pipeline connections are allowed by SOF topologies
+ * and required by some applications, but fragile as the
+ * pipeline state needs to be managed separately, generally by
+ * userspace code outside the control of firmware or the
+ * kernel driver. Not all applications want both pipelines
+ * operating in tandem, so in general there's no way to
+ * guarantee that these buffers won't over/underrun.
+ */
+ if (buffer->pipeline_id != comp->ipc_config.pipeline_id) {
+ comp_info(comp, "Cross-pipeline comp %d.%d <-> buf %d.%d, setting xrun-OK",
+ comp->ipc_config.pipeline_id, comp->ipc_config.id,
+ buffer->pipeline_id, buffer->id);
+ if (dir == PPL_CONN_DIR_COMP_TO_BUFFER)
+ audio_stream_set_overrun(&buffer->stream, true);
+ else
+ audio_stream_set_underrun(&buffer->stream, true);
+ }
+
  irq_local_enable(flags);
 
  return 0;