d3d12: Add gst_d3d12_flush_all_devices() method

... and removing implicit flushing behavior on GstD3D12Device::finalize

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/7929>

subprojects/gst-plugins-bad/gst-libs/gst/d3d12/gstd3d12device.cpp

@@ -367,20 +367,6 @@ public:
     return device;
   }
 
-  void ReleaseDevice (gint64 luid)
-  {
-    std::lock_guard <std::recursive_mutex> lk (lock_);
-    for (const auto & it : list_) {
-      if (it->adapter_luid == luid) {
-        if (it.use_count () == 1) {
-          it->Drain ();
-          it->ReportLiveObjects ();
-        }
-        return;
-      }
-    }
-  }
-
   void OnDeviceRemoved (gint64 luid)
   {
     std::lock_guard <std::recursive_mutex> lk (lock_);
@@ -498,6 +484,15 @@ public:
     }
   }
 
+  void FlushAll ()
+  {
+    std::lock_guard <std::recursive_mutex> lk (lock_);
+    for (const auto & it : list_) {
+      it->Drain ();
+      it->ReportLiveObjects ();
+    }
+  }
+
 private:
   DeviceCacheManager () {}
   ~DeviceCacheManager () {}
@@ -729,15 +724,8 @@ gst_d3d12_device_finalize (GObject * object)
 
   GST_DEBUG_OBJECT (self, "Finalize");
 
-  gint64 luid = 0;
-  if (self->priv->inner)
-    luid = self->priv->inner->adapter_luid;
-
   delete self->priv;
 
-  auto manager = DeviceCacheManager::GetInstance ();
-  manager->ReleaseDevice (luid);
-
   G_OBJECT_CLASS (parent_class)->finalize (object);
 }
 
@@ -2241,3 +2229,17 @@ gst_d3d12_device_non_zeroed_supported (GstD3D12Device * device)
 
   return device->priv->inner->non_zeroed_supported;
 }
+
+/**
+ * gst_d3d12_flush_all_devices:
+ *
+ * Flushes all devices and waits for completion of all scheduled GPU tasks
+ *
+ * Since: 1.26
+ */
+void
+gst_d3d12_flush_all_devices (void)
+{
+  auto manager = DeviceCacheManager::GetInstance ();
+  manager->FlushAll ();
+}

subprojects/gst-plugins-bad/gst-libs/gst/d3d12/gstd3d12utils.h

@@ -78,6 +78,10 @@ gboolean  gst_d3d12_get_copyable_footprints (GstD3D12Device * device,
                                              D3D12_PLACED_SUBRESOURCE_FOOTPRINT layout[GST_VIDEO_MAX_PLANES],
                                              guint64 * size);
 
+
+GST_D3D12_API
+void      gst_d3d12_flush_all_devices (void);
+
 GST_D3D12_API
 gboolean _gst_d3d12_result (HRESULT hr,
                             GstD3D12Device * device,

subprojects/gst-plugins-bad/sys/d3d12/plugin.cpp

@@ -73,6 +73,7 @@ static void
 plugin_deinit (gpointer data)
 {
   gst_d3d12_ipc_client_deinit ();
+  gst_d3d12_flush_all_devices ();
 }
 
 static gboolean