e1608: do not fight a hardware trigger, stop the scan on a failed connect, daemon drop timer in the mock

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/source/e1608/e1608_source.cpp

@@ -186,6 +186,7 @@ void E1608Source::open(SourceSink& sink) {
 
 void E1608Source::close() {
   if (state_ == State::Scanning) dev_.scan_stop();
+  scan_started_ = false;
   link_.close();
   connected_.store(false, std::memory_order_relaxed);
 }
@@ -212,6 +213,15 @@ void E1608Source::note(const std::string& msg) {
 }
 
 void E1608Source::fail(const std::string& msg, bool fatal) {
+  if (scan_started_) {
+    // The scan may have started before a later connect step failed: tell the board to stop, so it
+    // is not left scanning with nobody reading. Best effort; it must never throw out of here.
+    try {
+      dev_.scan_stop();
+    } catch (...) {
+    }
+    scan_started_ = false;
+  }
   link_.close();
   const bool was_up = connected_.exchange(false, std::memory_order_relaxed);
   note(msg);
@@ -283,6 +293,7 @@ void E1608Source::connect_and_start() {
   }
 
   link_.connect(host, cfg_.port, cfg_.code, cfg_.timeout_ms);
+  scan_started_ = false;
   cal_ = Calibration{};
   if (cfg_.calibrate && !dev_.read_calibration(cal_))
     note("calibration memory refused; using nominal values");
@@ -419,13 +430,16 @@ void E1608Source::check_status() {
     sink_->on_event(SourceEvent::Error, "scan overrun; restarting");
     restart_scan();
     pending_lost_ = 1;
-  } else if (!(st & 2) && cfg_.auto_restart) {
+  } else if (!(st & 2) && cfg_.auto_restart && cfg_.trigger == Trigger::None) {
+    // With a hardware trigger the board may report "not running" while it waits for the edge;
+    // restarting then would reset the wait forever, so only the overrun bit restarts the scan.
     restart_scan();
   }
 }
 
 void E1608Source::restart_scan() {
   dev_.scan_stop();
+  scan_started_ = false;
   pending_.clear();
   for (auto& r : ready_) r.clear();
   start_scan();
@@ -437,6 +451,7 @@ void E1608Source::start_scan() {
     throw LinkError(LinkError::Kind::Command, "the aggregate rate exceeds 250 kS/s");
   try {
     dev_.scan_start(queue_, cfg_.aggregate(), cfg_.ext_clock, cfg_.trigger);
+    scan_started_ = true;
   } catch (...) {
     // The board may have accepted the start (0x11) before a later step failed (the filler byte):
     // tell it to stop, so it is not left scanning with nobody reading.
@@ -444,6 +459,7 @@ void E1608Source::start_scan() {
       dev_.scan_stop();
     } catch (...) {
     }
+    scan_started_ = false;
     throw;
   }
 }

src/source/e1608/e1608_source.hpp

@@ -124,6 +124,7 @@ class E1608Source final : public DataSource {
   E1608Settings cfg_;
   SourceSink* sink_ = nullptr;
   State state_ = State::Down;
+  bool scan_started_ = false;  ///< a scan start succeeded and no stop has followed
   Link link_;
   Device dev_{link_};
   Calibration cal_;