diff --git a/dlls/d3d9/device.c b/dlls/d3d9/device.c
index 097b05f2919..5d1d292d898 100644
--- a/dlls/d3d9/device.c
+++ b/dlls/d3d9/device.c
@@ -3455,6 +3455,15 @@ static HRESULT WINAPI DECLSPEC_HOTPATCH d3d9_device_ResetEx(IDirect3DDevice9Ex *
         return D3DERR_INVALIDCALL;
     }
 
+    if (mode && (mode->Width != present_parameters->BackBufferWidth
+            || mode->Height != present_parameters->BackBufferHeight))
+    {
+        WARN("Mode and back buffer mismatch (mode %ux%u, backbuffer %ux%u).\n",
+                mode->Width, mode->Height,
+                present_parameters->BackBufferWidth, present_parameters->BackBufferHeight);
+        return D3DERR_INVALIDCALL;
+    }
+
     return d3d9_device_reset(device, present_parameters, mode);
 }
 
diff --git a/dlls/d3d9/tests/d3d9ex.c b/dlls/d3d9/tests/d3d9ex.c
index 63e9a30b1ef..05f1580a001 100644
--- a/dlls/d3d9/tests/d3d9ex.c
+++ b/dlls/d3d9/tests/d3d9ex.c
@@ -1563,15 +1563,26 @@ static void test_reset_ex(void)
     d3dpp.BackBufferWidth = modes[i].Width - 10;
     d3dpp.BackBufferHeight = modes[i].Height - 10;
     hr = IDirect3DDevice9Ex_ResetEx(device, &d3dpp, &modes[i]);
-    todo_wine ok(hr == D3DERR_INVALIDCALL, "Got unexpected hr %#x.\n", hr);
+    ok(hr == D3DERR_INVALIDCALL, "Got unexpected hr %#x.\n", hr);
     d3dpp.BackBufferWidth = modes[i].Width - 1;
     d3dpp.BackBufferHeight = modes[i].Height;
     hr = IDirect3DDevice9Ex_ResetEx(device, &d3dpp, &modes[i]);
-    todo_wine ok(hr == D3DERR_INVALIDCALL, "Got unexpected hr %#x.\n", hr);
+    ok(hr == D3DERR_INVALIDCALL, "Got unexpected hr %#x.\n", hr);
     d3dpp.BackBufferWidth = modes[i].Width;
     d3dpp.BackBufferHeight = modes[i].Height - 1;
     hr = IDirect3DDevice9Ex_ResetEx(device, &d3dpp, &modes[i]);
-    todo_wine ok(hr == D3DERR_INVALIDCALL, "Got unexpected hr %#x.\n", hr);
+    ok(hr == D3DERR_INVALIDCALL, "Got unexpected hr %#x.\n", hr);
+    d3dpp.BackBufferWidth = 0;
+    d3dpp.BackBufferHeight = 0;
+    hr = IDirect3DDevice9Ex_ResetEx(device, &d3dpp, &modes[i]);
+    ok(hr == D3DERR_INVALIDCALL, "Got unexpected hr %#x.\n", hr);
+    d3dpp.BackBufferWidth = modes[i].Width;
+    d3dpp.BackBufferHeight = modes[i].Height;
+    mode2 = modes[i];
+    mode2.Width = 0;
+    mode2.Height = 0;
+    hr = IDirect3DDevice9Ex_ResetEx(device, &d3dpp, &mode2);
+    ok(hr == D3DERR_INVALIDCALL, "Got unexpected hr %#x.\n", hr);
     hr = IDirect3DDevice9Ex_TestCooperativeLevel(device);
     ok(hr == D3D_OK, "Got unexpected cooperative level %#x.\n", hr);