- device_->session()->add_datafeed_callback([=]
- (shared_ptr<sigrok::Device> device, shared_ptr<Packet> packet) {
- data_feed_in(device, packet);
- });
+ if (device_) {
+ device_->session()->add_datafeed_callback([=]
+ (shared_ptr<sigrok::Device> device, shared_ptr<Packet> packet) {
+ data_feed_in(device, packet);
+ });
+
+ update_signals();
+ }