[idd] recovery: restore fallback display

Add a protocol-independent recovery channel outside LGMP so clients can
request a usable guest display even when transport versions differ.

Synchronize recovery state with the helper across driver restarts and
restore the configured topology without persisting temporary changes.

idd/LGIdd/display/CDeviceContext.cpp

@@ -44,8 +44,14 @@ CDeviceContext::CDeviceContext(WDFDEVICE wdfDevice) :
 
 CDeviceContext::~CDeviceContext()
 {
-  // Both callbacks dereference this context. Drain them before the subsystem
+  // These callbacks dereference this context. Drain them before the subsystem
   // members are destroyed in frame, control, host order.
+  if (m_recoveryHandlerSet)
+  {
+    g_pipe.ClearRecoveryHandler(this);
+    m_recoveryHandlerSet = false;
+  }
+
   if (m_initTimer)
   {
     WdfTimerStop(m_initTimer, TRUE);
@@ -379,8 +385,9 @@ void CDeviceContext::FinishInit(UINT connectorIndex)
 {
   CDisplayConfiguration::Description description =
     m_displayConfiguration.GetDescription();
-  m_monitorManager.Create(
-    connectorIndex, m_adapter, std::move(description.edid), this);
+  if (m_monitorManager.Create(
+      connectorIndex, m_adapter, std::move(description.edid), this))
+    m_transport->SyncRecovery();
 }
 
 void CDeviceContext::ReplugMonitor()
@@ -460,7 +467,90 @@ void CDeviceContext::SetResolution(uint32_t width, uint32_t height)
 
 bool CDeviceContext::InitializeTransport()
 {
-  return m_transport && m_transport->Initialize();
+  if (!m_transport)
+    return false;
+
+  if (m_transportTimer)
+    return true;
+
+  g_pipe.SetRecoveryHandler(
+    [](void * opaque, uint64_t session, uint32_t serial, bool active,
+       LGPipeMsg::Type result)
+    {
+      CDeviceContext * context =
+        static_cast<CDeviceContext *>(opaque);
+
+      ITransport::Recovery state = ITransport::Recovery::FAILED;
+      uint32_t error = ERROR_SUCCESS;
+      switch (result)
+      {
+        case LGPipeMsg::RECOVERY_OFF:
+          state = ITransport::Recovery::NORMAL;
+          break;
+
+        case LGPipeMsg::RECOVERY_ON:
+          state = ITransport::Recovery::ACTIVE;
+          break;
+
+        case LGPipeMsg::RECOVERY_FAILED:
+          error = ERROR_GEN_FAILURE;
+          break;
+
+        case LGPipeMsg::RECOVERY_NO_DISPLAY:
+          error = ERROR_NOT_FOUND;
+          break;
+
+        default:
+          return;
+      }
+
+      context->m_transport->RecoveryStatus(
+        session, serial, active, state, error);
+    },
+    this);
+  m_recoveryHandlerSet = true;
+
+  // Claim the pipe recovery channel before initializing the producer session
+  // so no request cached by a prior device context can cross the handoff.
+  if (!m_transport->Initialize())
+  {
+    g_pipe.ClearRecoveryHandler(this);
+    m_recoveryHandlerSet = false;
+    return false;
+  }
+
+  WDF_TIMER_CONFIG config;
+  WDF_TIMER_CONFIG_INIT_PERIODIC(&config,
+    [](WDFTIMER timer) -> void
+    {
+      WDFOBJECT parent = WdfTimerGetParentObject(timer);
+      auto wrapper = WdfObjectGet_CDeviceContextWrapper(parent);
+      wrapper->context->TransportTimer();
+    },
+    10);
+  config.AutomaticSerialization = FALSE;
+
+  /**
+   * Documentation states that Dispatch is not available under UMDF,
+   * however using Passive returns a not-supported error and Dispatch works.
+   */
+  WDF_OBJECT_ATTRIBUTES attribs;
+  WDF_OBJECT_ATTRIBUTES_INIT(&attribs);
+  attribs.ParentObject   = m_wdfDevice;
+  attribs.ExecutionLevel = WdfExecutionLevelDispatch;
+
+  NTSTATUS status = WdfTimerCreate(
+    &config, &attribs, &m_transportTimer);
+  if (!NT_SUCCESS(status))
+  {
+    g_pipe.ClearRecoveryHandler(this);
+    m_recoveryHandlerSet = false;
+    DEBUG_ERROR_HR(status, "Transport timer creation failed");
+    return false;
+  }
+
+  WdfTimerStart(m_transportTimer, WDF_REL_TIMEOUT_IN_MS(10));
+  return true;
 }
 
 bool CDeviceContext::SetupTransport(size_t alignSize)
@@ -471,36 +561,6 @@ bool CDeviceContext::SetupTransport(size_t alignSize)
   {
     if (!InitializeTransport() || !m_transport->Setup(alignSize))
       return false;
-
-    WDF_TIMER_CONFIG config;
-    WDF_TIMER_CONFIG_INIT_PERIODIC(&config,
-      [](WDFTIMER timer) -> void
-      {
-        WDFOBJECT parent = WdfTimerGetParentObject(timer);
-        auto wrapper = WdfObjectGet_CDeviceContextWrapper(parent);
-        wrapper->context->TransportTimer();
-      },
-      10);
-    config.AutomaticSerialization = FALSE;
-
-    /**
-     * Documentation states that Dispatch is not available under UMDF,
-     * however using Passive returns a not-supported error and Dispatch works.
-     */
-    WDF_OBJECT_ATTRIBUTES attribs;
-    WDF_OBJECT_ATTRIBUTES_INIT(&attribs);
-    attribs.ParentObject   = m_wdfDevice;
-    attribs.ExecutionLevel = WdfExecutionLevelDispatch;
-
-    NTSTATUS status = WdfTimerCreate(
-      &config, &attribs, &m_transportTimer);
-    if (!NT_SUCCESS(status))
-    {
-      DEBUG_ERROR_HR(status, "Timer creation failed");
-      return false;
-    }
-
-    WdfTimerStart(m_transportTimer, WDF_REL_TIMEOUT_IN_MS(10));
   }
 
   IInputTransport * input = m_transport->Input();
@@ -542,3 +602,9 @@ void CDeviceContext::OnSetResolution(uint32_t width, uint32_t height)
 {
   SetResolution(width, height);
 }
+
+void CDeviceContext::OnRecoveryRequest(
+  uint64_t session, uint32_t serial, bool active)
+{
+  g_pipe.SetRecovery(this, session, serial, active);
+}

idd/LGIdd/display/CDeviceContext.h

@@ -51,7 +51,8 @@ private:
   CDisplayConfiguration       m_displayConfiguration;
   CMonitorManager             m_monitorManager;
 
-  WDFTIMER m_transportTimer = nullptr;
+  WDFTIMER m_transportTimer     = nullptr;
+  bool     m_recoveryHandlerSet = false;
 
   UINT m_iddCxVersion    = 0;
   bool m_hasIddCx110DDIs = false;
@@ -67,6 +68,8 @@ private:
   void TransportTimer();
   void OnSetCursorPos(int32_t x, int32_t y) override;
   void OnSetResolution(uint32_t width, uint32_t height) override;
+  void OnRecoveryRequest(
+    uint64_t session, uint32_t serial, bool active) override;
   void SetResolution(uint32_t width, uint32_t height);
 
 public:

idd/LGIdd/display/CMonitorManager.cpp

@@ -23,7 +23,7 @@
 #include "display/CMonitorContext.h"
 #include "CDebug.h"
 
-void CMonitorManager::Create(UINT connectorIndex, IDDCX_ADAPTER adapter,
+bool CMonitorManager::Create(UINT connectorIndex, IDDCX_ADAPTER adapter,
   std::vector<BYTE> edid, CDeviceContext * owner)
 {
   DEBUG_INFO("Creating monitor on connector %u", connectorIndex);
@@ -38,7 +38,7 @@ void CMonitorManager::Create(UINT connectorIndex, IDDCX_ADAPTER adapter,
   if (haveMonitor)
   {
     DEBUG_WARN("FinishInit skipped: a monitor already exists");
-    return;
+    return false;
   }
 
   WDF_OBJECT_ATTRIBUTES attr;
@@ -61,7 +61,7 @@ void CMonitorManager::Create(UINT connectorIndex, IDDCX_ADAPTER adapter,
   if (FAILED(hr))
   {
     DEBUG_ERROR_HR(hr, "Failed to create the monitor container ID");
-    return;
+    return false;
   }
 
   IDARG_IN_MONITORCREATE create = {};
@@ -73,7 +73,7 @@ void CMonitorManager::Create(UINT connectorIndex, IDDCX_ADAPTER adapter,
   if (!NT_SUCCESS(status))
   {
     DEBUG_ERROR_HR(status, "IddCxMonitorCreate Failed");
-    return;
+    return false;
   }
 
   DEBUG_INFO("Monitor object created (%p)", createOut.MonitorObject);
@@ -91,10 +91,11 @@ void CMonitorManager::Create(UINT connectorIndex, IDDCX_ADAPTER adapter,
   if (FAILED(status))
   {
     DEBUG_ERROR_HR(status, "IddCxMonitorArrival Failed");
-    return;
+    return false;
   }
 
   DEBUG_INFO("Monitor arrival reported successfully");
+  return true;
 }
 
 CMonitorManager::ReplugAction CMonitorManager::Replug()

idd/LGIdd/display/CMonitorManager.h

@@ -75,7 +75,7 @@ private:
   std::atomic<LONG> m_replugQueued = 0;
 
 public:
-  void Create(UINT connectorIndex, IDDCX_ADAPTER adapter,
+  bool Create(UINT connectorIndex, IDDCX_ADAPTER adapter,
     std::vector<BYTE> edid, CDeviceContext * owner);
   ReplugAction Replug();
   void RequestMode(const CSettings::DisplayMode& mode);