Stop detaching usbip imports we cannot prove are ours

DS4Windows/DS4Control/ControlService.cs

@@ -1740,15 +1740,21 @@ public bool Start(bool showlog = true)
                     AssignInitialDevices();
                     StartupDiag("AssignInitialDevices end");
 
-                    // A force-closed prior development build can leave its
-                    // USB/IP output imported. Remove those ports before HID
-                    // discovery or DS4Windows will ingest its own VIIPER DS4,
-                    // create a second output/UAC endpoint, and recurse.
-                    ViiperUsbipPortManager.DetachStaleLocalViiperPorts();
-                    // Let usbccgp/HID finish publishing removal before the
-                    // first input snapshot; otherwise a detached interface can
-                    // remain enumerable for one final discovery pass.
-                    Thread.Sleep(250);
+                    // This used to detach "stale" local VIIPER imports before
+                    // HID discovery so a force-closed prior session's output
+                    // could not be ingested as an input and recursed on. It
+                    // detaches nothing now: identified only by controller
+                    // VID/PID and a localhost URL, another application's live
+                    // virtual pad is indistinguishable from a leftover, and on
+                    // 2026-07-31 the sweep disconnected one mid-game. The pass
+                    // still runs for its log line — any unmanaged local import
+                    // is named, with a pointer to the Settings backend-process
+                    // card, which can attribute leftovers and clear them with
+                    // consent. The self-ingestion case that motivated the
+                    // detach is accepted as a residual risk until inputs can
+                    // recognise this app's own virtual pads; the startup
+                    // warning above fires for exactly that state.
+                    ViiperUsbipPortManager.ObserveLocalImports();
 
                     StartupDiag("DS4Devices.findControllers dispatch begin");
                     eventDispatcher.Invoke(() =>

DS4Windows/DS4Control/Viiper/ViiperBackendDebugger.cs

@@ -226,15 +226,15 @@ private void RunDeviceProbe(ViiperVirtualDeviceType type, CancellationToken canc
                 int feedbackLength = ViiperStatePacketBuilder.GetFeedbackLength(type);
                 Log($"Device={type} viiperName={viiperDeviceName} packetLength={packetLength} feedbackLength={feedbackLength}");
 
-                // The stale-import sweep used to live inside CreateDeviceAndOpenStream;
-                // it now gates the output ladder in ViiperOutDevice instead, so this
-                // diagnostic runs its own. Reported rather than enforced: the point of
-                // the debugger is to say what it found.
-                ViiperStalePortSweep sweep =
-                    ViiperUsbipPortManager.DetachStaleLocalViiperPorts();
-                Log(sweep.Cleared
-                    ? "Stale local VIIPER imports: none present"
-                    : $"Stale local VIIPER imports UNPROVEN: {sweep.Reason}");
+                // The observation pass that gates the output ladder in
+                // ViiperOutDevice; run here too so the diagnostic records the
+                // same view. It only reads — unmanaged imports are logged by
+                // the pass itself and never touched.
+                ViiperImportObservation observation =
+                    ViiperUsbipPortManager.ObserveLocalImports();
+                Log(observation.Observed
+                    ? "Imported usbip ports: readable"
+                    : $"Imported usbip ports UNREADABLE: {observation.Reason}");
 
                 using ViiperDeviceStream stream = client.CreateDeviceAndOpenStream(type);
                 Log($"Device={type} create/open stream OK");