fix dcam AE feedback loop with IR LEDs (#21651)

selfdrive/boardd/boardd.cc

@@ -411,6 +411,8 @@ void hardware_control_thread() {
   bool prev_charging_disabled = false;
   unsigned int cnt = 0;
 
+  FirstOrderFilter integ_lines_filter(0, 10.0, 0.05);
+
   while (!do_exit && panda->connected) {
     cnt++;
     sm.update(1000); // TODO: what happens if EINTR is sent while in sm.update?
@@ -443,6 +445,10 @@ void hardware_control_thread() {
     if (sm.updated("driverCameraState")) {
       auto event = sm["driverCameraState"];
       int cur_integ_lines = event.getDriverCameraState().getIntegLines();
+
+      if (Hardware::TICI()) {
+        cur_integ_lines = integ_lines_filter.update(cur_integ_lines * 2.5);
+      }
       last_front_frame_t = event.getLogMonoTime();
 
       if (cur_integ_lines <= CUTOFF_IL) {