diff --git a/dlls/d3d8/device.c b/dlls/d3d8/device.c
index eb26d7386c1..450a5ffb3ca 100644
--- a/dlls/d3d8/device.c
+++ b/dlls/d3d8/device.c
@@ -334,17 +334,11 @@ static ULONG WINAPI IDirect3DDevice8Impl_Release(LPDIRECT3DDEVICE8 iface) {
 }
 
 /* IDirect3DDevice Interface follow: */
-static HRESULT WINAPI IDirect3DDevice8Impl_TestCooperativeLevel(LPDIRECT3DDEVICE8 iface) {
-    IDirect3DDevice8Impl *This = (IDirect3DDevice8Impl *)iface;
-    HRESULT hr;
-
+static HRESULT WINAPI IDirect3DDevice8Impl_TestCooperativeLevel(IDirect3DDevice8 *iface)
+{
     TRACE("iface %p.\n", iface);
 
-    wined3d_mutex_lock();
-    hr = IWineD3DDevice_TestCooperativeLevel(This->WineD3DDevice);
-    wined3d_mutex_unlock();
-
-    return hr;
+    return D3D_OK;
 }
 
 static UINT WINAPI  IDirect3DDevice8Impl_GetAvailableTextureMem(LPDIRECT3DDEVICE8 iface) {
diff --git a/dlls/d3d9/device.c b/dlls/d3d9/device.c
index 1151d990ab6..dfb6b266279 100644
--- a/dlls/d3d9/device.c
+++ b/dlls/d3d9/device.c
@@ -280,22 +280,19 @@ static ULONG WINAPI DECLSPEC_HOTPATCH IDirect3DDevice9Impl_Release(LPDIRECT3DDEV
 }
 
 /* IDirect3DDevice Interface follow: */
-static HRESULT  WINAPI  IDirect3DDevice9Impl_TestCooperativeLevel(LPDIRECT3DDEVICE9EX iface) {
+static HRESULT WINAPI IDirect3DDevice9Impl_TestCooperativeLevel(IDirect3DDevice9Ex *iface)
+{
     IDirect3DDevice9Impl *This = (IDirect3DDevice9Impl *)iface;
-    HRESULT hr;
 
     TRACE("iface %p.\n", iface);
 
-    wined3d_mutex_lock();
-    hr = IWineD3DDevice_TestCooperativeLevel(This->WineD3DDevice);
-    wined3d_mutex_unlock();
-
-    if(hr == WINED3D_OK && This->notreset) {
-        TRACE("D3D9 Device is marked not reset\n");
-        hr = D3DERR_DEVICENOTRESET;
+    if (This->notreset)
+    {
+        TRACE("D3D9 device is marked not reset.\n");
+        return D3DERR_DEVICENOTRESET;
     }
 
-    return hr;
+    return D3D_OK;
 }
 
 static UINT     WINAPI  IDirect3DDevice9Impl_GetAvailableTextureMem(LPDIRECT3DDEVICE9EX iface) {
diff --git a/dlls/ddraw/ddraw.c b/dlls/ddraw/ddraw.c
index 351ebdaa824..aeaffbd6af7 100644
--- a/dlls/ddraw/ddraw.c
+++ b/dlls/ddraw/ddraw.c
@@ -1187,53 +1187,8 @@ static HRESULT WINAPI IDirectDrawImpl_GetScanLine(IDirectDraw7 *iface, DWORD *Sc
 static HRESULT WINAPI
 IDirectDrawImpl_TestCooperativeLevel(IDirectDraw7 *iface)
 {
-    IDirectDrawImpl *This = (IDirectDrawImpl *)iface;
-    HRESULT hr;
-    TRACE("(%p)\n", This);
+    TRACE("iface %p.\n", iface);
 
-    EnterCriticalSection(&ddraw_cs);
-    /* Description from MSDN:
-     * For fullscreen apps return DDERR_NOEXCLUSIVEMODE if the user switched
-     * away from the app with e.g. alt-tab. Windowed apps receive
-     * DDERR_EXCLUSIVEMODEALREADYSET if another application created a
-     * DirectDraw object in exclusive mode. DDERR_WRONGMODE is returned,
-     * when the video mode has changed
-     */
-
-    hr =  IWineD3DDevice_TestCooperativeLevel(This->wineD3DDevice);
-
-    /* Fix the result value. These values are mapped from their
-     * d3d9 counterpart.
-     */
-    switch(hr)
-    {
-        case WINED3DERR_DEVICELOST:
-            if(This->cooperative_level & DDSCL_EXCLUSIVE)
-            {
-                LeaveCriticalSection(&ddraw_cs);
-                return DDERR_NOEXCLUSIVEMODE;
-            }
-            else
-            {
-                LeaveCriticalSection(&ddraw_cs);
-                return DDERR_EXCLUSIVEMODEALREADYSET;
-            }
-
-        case WINED3DERR_DEVICENOTRESET:
-            LeaveCriticalSection(&ddraw_cs);
-            return DD_OK;
-
-        case WINED3D_OK:
-            LeaveCriticalSection(&ddraw_cs);
-            return DD_OK;
-
-        case WINED3DERR_DRIVERINTERNALERROR:
-        default:
-            ERR("(%p) Unexpected return value %08x from wineD3D, "
-                " returning DD_OK\n", This, hr);
-    }
-
-    LeaveCriticalSection(&ddraw_cs);
     return DD_OK;
 }
 
diff --git a/dlls/wined3d/device.c b/dlls/wined3d/device.c
index c48424ebf49..136f3969255 100644
--- a/dlls/wined3d/device.c
+++ b/dlls/wined3d/device.c
@@ -6494,31 +6494,6 @@ static BOOL     WINAPI  IWineD3DDeviceImpl_ShowCursor(IWineD3DDevice* iface, BOO
     return oldVisible;
 }
 
-static HRESULT  WINAPI  IWineD3DDeviceImpl_TestCooperativeLevel(IWineD3DDevice* iface) {
-    IWineD3DDeviceImpl *This = (IWineD3DDeviceImpl *) iface;
-    IWineD3DResourceImpl *resource;
-    TRACE("(%p) : state (%u)\n", This, This->state);
-
-    /* TODO: Implement wrapping of the WndProc so that mimimize and maximize can be monitored and the states adjusted. */
-    switch (This->state) {
-    case WINED3D_OK:
-        return WINED3D_OK;
-    case WINED3DERR_DEVICELOST:
-        {
-            LIST_FOR_EACH_ENTRY(resource, &This->resources, IWineD3DResourceImpl, resource.resource_list_entry) {
-                if (resource->resource.pool == WINED3DPOOL_DEFAULT)
-                    return WINED3DERR_DEVICENOTRESET;
-            }
-            return WINED3DERR_DEVICELOST;
-        }
-    case WINED3DERR_DRIVERINTERNALERROR:
-        return WINED3DERR_DRIVERINTERNALERROR;
-    }
-
-    /* Unknown state */
-    return WINED3DERR_DRIVERINTERNALERROR;
-}
-
 static HRESULT WINAPI evict_managed_resource(IWineD3DResource *resource, void *data) {
     TRACE("checking resource %p for eviction\n", resource);
     if(((IWineD3DResourceImpl *) resource)->resource.pool == WINED3DPOOL_MANAGED) {
@@ -7154,7 +7129,6 @@ static const IWineD3DDeviceVtbl IWineD3DDevice_Vtbl =
     IWineD3DDeviceImpl_SetCursorProperties,
     IWineD3DDeviceImpl_SetCursorPosition,
     IWineD3DDeviceImpl_ShowCursor,
-    IWineD3DDeviceImpl_TestCooperativeLevel,
     /*** Getters and setters **/
     IWineD3DDeviceImpl_SetClipPlane,
     IWineD3DDeviceImpl_GetClipPlane,
@@ -7278,9 +7252,6 @@ HRESULT device_init(IWineD3DDeviceImpl *device, IWineD3DImpl *wined3d,
     device->surface_alignment = wined3d->dxVersion == 7 ? DDRAW_PITCH_ALIGNMENT : D3D8_PITCH_ALIGNMENT;
     device->posFixup[0] = 1.0f; /* This is needed to get the x coord unmodified through a MAD. */
 
-    /* Set the state up as invalid until the device is fully created. */
-    device->state = WINED3DERR_DRIVERINTERNALERROR;
-
     /* Get the initial screen setup for ddraw. */
     hr = IWineD3D_GetAdapterDisplayMode((IWineD3D *)wined3d, adapter_idx, &mode);
     if (FAILED(hr))
@@ -7330,9 +7301,6 @@ HRESULT device_init(IWineD3DDeviceImpl *device, IWineD3DImpl *wined3d,
 
     device->blitter = select_blit_implementation(adapter, device_type);
 
-    /* Set the state of the device to valid. */
-    device->state = WINED3D_OK;
-
     return WINED3D_OK;
 }
 
diff --git a/dlls/wined3d/wined3d_private.h b/dlls/wined3d/wined3d_private.h
index 9299a6e04d3..12685d20518 100644
--- a/dlls/wined3d/wined3d_private.h
+++ b/dlls/wined3d/wined3d_private.h
@@ -1555,9 +1555,6 @@ struct IWineD3DDeviceImpl
     /* Textures for when no other textures are mapped */
     UINT                          dummyTextureName[MAX_TEXTURES];
 
-    /* Device state management */
-    HRESULT                 state;
-
     /* DirectDraw stuff */
     DWORD ddraw_width, ddraw_height;
     WINED3DFORMAT ddraw_format;
diff --git a/include/wine/wined3d.idl b/include/wine/wined3d.idl
index 2534fbbc06b..176e602bf71 100644
--- a/include/wine/wined3d.idl
+++ b/include/wine/wined3d.idl
@@ -3076,8 +3076,6 @@ interface IWineD3DDevice : IWineD3DBase
     BOOL ShowCursor(
         [in] BOOL show
     );
-    HRESULT TestCooperativeLevel(
-    );
     HRESULT SetClipPlane(
         [in] DWORD plane_idx,
         [in] const float *plane