diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/android/gstvkdisplay_android.c b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/android/gstvkdisplay_android.c
index 5a4156d7d9..79f5f73afc 100644
--- a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/android/gstvkdisplay_android.c
+++ b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/android/gstvkdisplay_android.c
@@ -64,7 +64,7 @@ gst_vulkan_display_android_finalize (GObject * object)
  *
  * Create a new #GstVulkanDisplayAndroid.
  *
- * Returns: (transfer full): a new #GstVulkanDisplayAndroid or %NULL
+ * Returns: (transfer full): a new #GstVulkanDisplayAndroid
  */
 GstVulkanDisplayAndroid *
 gst_vulkan_display_android_new (void)
diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/cocoa/gstvkdisplay_cocoa.m b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/cocoa/gstvkdisplay_cocoa.m
index 27519a6150..6daa53db5f 100644
--- a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/cocoa/gstvkdisplay_cocoa.m
+++ b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/cocoa/gstvkdisplay_cocoa.m
@@ -221,7 +221,7 @@ gst_vulkan_display_cocoa_finalize (GObject * object)
  *
  * Create a new #GstVulkanDisplayCocoa.
  *
- * Returns: (transfer full): a new #GstVulkanDisplayCocoa or %NULL
+ * Returns: (transfer full): a new #GstVulkanDisplayCocoa
  */
 GstVulkanDisplayCocoa *
 gst_vulkan_display_cocoa_new (void)
diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkdevice.c b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkdevice.c
index 639406de0f..005bf98029 100644
--- a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkdevice.c
+++ b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkdevice.c
@@ -424,7 +424,7 @@ gst_vulkan_device_foreach_queue (GstVulkanDevice * device,
  *
  * Performs `vkGetDeviceProcAddr()` with @device and @name
  *
- * Returns: the function pointer for @name or %NULL
+ * Returns: (nullable): the function pointer for @name or %NULL
  *
  * Since: 1.18
  */
@@ -445,7 +445,7 @@ gst_vulkan_device_get_proc_address (GstVulkanDevice * device,
  * gst_vulkan_device_get_instance:
  * @device: a #GstVulkanDevice
  *
- * Returns: (transfer full): the #GstVulkanInstance used to create this @device
+ * Returns: (transfer full) (nullable): the #GstVulkanInstance used to create this @device
  *
  * Since: 1.18
  */
@@ -629,7 +629,7 @@ gst_vulkan_device_run_context_query (GstElement * element,
  * @device: a #GstVulkanDevice
  * @error: a #GError to fill on failure
  *
- * Returns: a new #GstVulkanFence or %NULL
+ * Returns: (transfer full) (nullable): a new #GstVulkanFence or %NULL
  *
  * Since: 1.18
  */
diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkdisplay.c b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkdisplay.c
index fc87417b66..82756d7d92 100644
--- a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkdisplay.c
+++ b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkdisplay.c
@@ -206,7 +206,7 @@ gst_vulkan_display_finalize (GObject * object)
  * @instance: a #GstVulkanInstance
  * @type: the #GstVulkanDisplayType to create
  *
- * Returns: (transfer full): a new #GstVulkanDisplay or %NULL if e.g. @type is
+ * Returns: (transfer full) (nullable): a new #GstVulkanDisplay or %NULL if e.g. @type is
  * unsupported
  *
  * Since: 1.18
@@ -326,7 +326,7 @@ gst_vulkan_display_get_handle_type (GstVulkanDisplay * display)
  * gst_vulkan_display_create_window:
  * @display: a #GstVulkanDisplay
  *
- * Returns: (transfer full): a new #GstVulkanWindow for @display or %NULL.
+ * Returns: (transfer full) (nullable): a new #GstVulkanWindow for @display or %NULL.
  *
  * Since: 1.18
  */
@@ -400,7 +400,7 @@ window_weak_list_to_strong (GstVulkanDisplay * display)
  * first argument to @compare_func is the #GstVulkanWindow being checked and the
  * second argument is @data.
  *
- * Returns: (transfer full): The first #GstVulkanWindow that causes a match
+ * Returns: (transfer full) (nullable): The first #GstVulkanWindow that causes a match
  *          from @compare_func
  *
  * Since: 1.18
@@ -633,7 +633,7 @@ gst_vulkan_display_choose_type (GstVulkanInstance * instance)
  * gst_vulkan_display_type_to_extension_string:
  * @type: a #GstVulkanDisplayType
  *
- * Returns: the Vulkan extension string required for creating a VkSurfaceKHR
+ * Returns: (nullable): the Vulkan extension string required for creating a VkSurfaceKHR
  * using a window system handle or %NULL
  *
  * Since: 1.18
diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkfence.c b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkfence.c
index 9e03a24b50..c2db919cd9 100644
--- a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkfence.c
+++ b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkfence.c
@@ -87,7 +87,7 @@ gst_vulkan_fence_free (GstVulkanFence * fence)
 /**
  * gst_vulkan_fence_new:
  * @device: the parent #GstVulkanDevice
- * @error: a #GError for the failure condition
+ * @error: (optional): a #GError for the failure condition
  *
  * Returns: whether a new #GstVulkanFence or %NULL on error
  *
diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkformat.c b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkformat.c
index 4d186852b1..98fe2224de 100644
--- a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkformat.c
+++ b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkformat.c
@@ -419,7 +419,7 @@ FIXME: implement:
  * gst_vulkan_format_get_info:
  * @format: a valid `VkFormat`
  *
- * Returns: the #GstVulkanFormatInfo for @format or %NULL
+ * Returns: (nullable): the #GstVulkanFormatInfo for @format or %NULL
  *
  * Since: 1.18
  */
diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkinstance.c b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkinstance.c
index 46f9148dad..58631fcdf4 100644
--- a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkinstance.c
+++ b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkinstance.c
@@ -1071,7 +1071,7 @@ error:
  *
  * Performs `vkGetInstanceProcAddr()` with @instance and @name
  *
- * Returns: the function pointer for @name or %NULL
+ * Returns: (nullable): the function pointer for @name or %NULL
  *
  * Since: 1.18
  */
@@ -1095,6 +1095,7 @@ gst_vulkan_instance_get_proc_address (GstVulkanInstance * instance,
 /**
  * gst_vulkan_instance_create_device:
  * @instance: a #GstVulkanInstance
+ * @error: (optional): a #GError
  *
  * Returns: (transfer full): a new #GstVulkanDevice
  *
diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkqueue.c b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkqueue.c
index 025b9b235b..b4625572d2 100644
--- a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkqueue.c
+++ b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkqueue.c
@@ -97,7 +97,7 @@ gst_vulkan_queue_dispose (GObject * object)
  * gst_vulkan_queue_get_device
  * @queue: a #GstVulkanQueue
  *
- * Returns: (transfer full): the #GstVulkanDevice for @queue
+ * Returns: (transfer full) (nullable): the #GstVulkanDevice for @queue
  *
  * Since: 1.18
  */
@@ -112,7 +112,7 @@ gst_vulkan_queue_get_device (GstVulkanQueue * queue)
 /**
  * gst_vulkan_queue_create_command_pool:
  * @queue: a #GstVulkanQueue
- * @error: a #GError
+ * @error: (optional): a #GError
  *
  * Returns: (transfer full): a new #GstVUlkanCommandPool or %NULL
  *
diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkutils.c b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkutils.c
index 7f28d25ab4..d17bc26251 100644
--- a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkutils.c
+++ b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/gstvkutils.c
@@ -489,7 +489,7 @@ gst_vulkan_get_or_create_image_view (GstVulkanImageMemory * image)
  * @device: a #GstVulkanDevice
  * @code: the SPIR-V shader byte code
  * @size: length of @code.  Must be a multiple of 4
- * @error: a #GError to fill on failure
+ * @error: (optional): a #GError to fill on failure
  *
  * Returns: (transfer full): a #GstVulkanHandle for @image matching the
  *                           original layout and format of @image or %NULL
diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/ios/gstvkdisplay_ios.m b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/ios/gstvkdisplay_ios.m
index 0bd3ff7a3d..9b018fe1d4 100644
--- a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/ios/gstvkdisplay_ios.m
+++ b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/ios/gstvkdisplay_ios.m
@@ -65,7 +65,7 @@ gst_vulkan_display_ios_finalize (GObject * object)
  *
  * Create a new #GstVulkanDisplayIos.
  *
- * Returns: (transfer full): a new #GstVulkanDisplayIos or %NULL
+ * Returns: (transfer full): a new #GstVulkanDisplayIos
  */
 GstVulkanDisplayIos *
 gst_vulkan_display_ios_new (void)
diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/wayland/gstvkdisplay_wayland.c b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/wayland/gstvkdisplay_wayland.c
index ae9c172c2a..7aa74651eb 100644
--- a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/wayland/gstvkdisplay_wayland.c
+++ b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/wayland/gstvkdisplay_wayland.c
@@ -105,12 +105,12 @@ gst_vulkan_display_wayland_finalize (GObject * object)
 
 /**
  * gst_vulkan_display_wayland_new:
- * @name: (allow-none): a display name
+ * @name: (nullable): a display name
  *
  * Create a new #GstVulkanDisplayWayland from the wayland display name.  See `wl_display_connect`()
  * for details on what is a valid name.
  *
- * Returns: (transfer full): a new #GstVulkanDisplayWayland or %NULL
+ * Returns: (transfer full) (nullable): a new #GstVulkanDisplayWayland or %NULL
  *
  * Since: 1.18
  */
@@ -118,17 +118,20 @@ GstVulkanDisplayWayland *
 gst_vulkan_display_wayland_new (const gchar * name)
 {
   GstVulkanDisplayWayland *ret;
+  struct wl_display *display;
 
-  ret = g_object_new (GST_TYPE_VULKAN_DISPLAY_WAYLAND, NULL);
-  gst_object_ref_sink (ret);
-  ret->display = wl_display_connect (name);
+  display = wl_display_connect (name);
 
-  if (!ret->display) {
+  if (!display) {
     GST_ERROR ("Failed to open Wayland display connection with name, \'%s\'",
         name);
     return NULL;
   }
 
+  ret = g_object_new (GST_TYPE_VULKAN_DISPLAY_WAYLAND, NULL);
+  gst_object_ref_sink (ret);
+  ret->display = display;
+
   /* connecting the listeners after attaching the event source will race with
    * the source and the source may eat an event that we're waiting for and
    * deadlock */
diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/xcb/gstvkdisplay_xcb.c b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/xcb/gstvkdisplay_xcb.c
index fb07c94b23..a9f03498aa 100644
--- a/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/xcb/gstvkdisplay_xcb.c
+++ b/subprojects/gst-plugins-bad/gst-libs/gst/vulkan/xcb/gstvkdisplay_xcb.c
@@ -82,12 +82,12 @@ _get_screen_from_connection (xcb_connection_t * connection, int screen_no)
 
 /**
  * gst_vulkan_display_xcb_new:
- * @name: (allow-none): a display name
+ * @name: (nullable): a display name
  *
  * Create a new #GstVulkanDisplayXCB from the xcb display name.  See XOpenDisplay\()
  * for details on what is a valid name.
  *
- * Returns: (transfer full): a new #GstVulkanDisplayXCB or %NULL
+ * Returns: (transfer full) (nullable): a new #GstVulkanDisplayXCB or %NULL
  *
  * Since: 1.18
  */