fix: non-blocking response drain using setblocking(False)

scripts/led-matrix-viz.py

@@ -74,8 +74,6 @@ def main():
 
     _poll.register(sock, POLLIN)
 
-    router_resp = b""
-
     active_notes = set()
     last_sent_params = None
     pending_bytes = None
@@ -145,13 +143,17 @@ def main():
             if ok:
                 pending_bytes = None
                 frames_sent += 1
-                # Drain exactly one response to keep router buffer clear
+                # Drain pending responses so router buffer stays clear
+                router.setblocking(False)
                 try:
-                    router.settimeout(0.001)
+                    while True:
-                    router.recv(4096)
+                        chunk = router.recv(4096)
-                except (BlockingIOError, socket.timeout, OSError):
+                        if not chunk:
+                            break
+                except (BlockingIOError, OSError):
                     pass
                 finally:
+                    router.setblocking(True)
                     router.settimeout(0.01)
             else:
                 frames_dropped += 1