diff --git a/dlls/ddraw/ddraw/thunks.c b/dlls/ddraw/ddraw/thunks.c
index 10296fa238a..9bb7a8ca407 100644
--- a/dlls/ddraw/ddraw/thunks.c
+++ b/dlls/ddraw/ddraw/thunks.c
@@ -326,9 +326,13 @@ struct displaymodescallback_context
 static HRESULT CALLBACK
 EnumDisplayModesCallbackThunk(LPDDSURFACEDESC2 pDDSD2, LPVOID context)
 {
+    DDSURFACEDESC DDSD;
     struct displaymodescallback_context *cbcontext = context;
 
-    return cbcontext->func((LPDDSURFACEDESC)pDDSD2, cbcontext->context);
+    memcpy(&DDSD,pDDSD2,sizeof DDSD);
+    DDSD.dwSize = sizeof DDSD;
+
+    return cbcontext->func(&DDSD, cbcontext->context);
 }
 
 static HRESULT WINAPI
diff --git a/include/ddraw.h b/include/ddraw.h
index 29e7943c316..7ec10e6c207 100644
--- a/include/ddraw.h
+++ b/include/ddraw.h
@@ -979,7 +979,7 @@ typedef struct _DDSURFACEDESC
 
 typedef struct _DDSURFACEDESC2
 {
-	DWORD	dwSize;		/* 0: size of the DDSURFACEDESC structure*/
+	DWORD	dwSize;		/* 0: size of the DDSURFACEDESC2 structure*/
 	DWORD	dwFlags;	/* 4: determines what fields are valid*/
 	DWORD	dwHeight;	/* 8: height of surface to be created*/
 	DWORD	dwWidth;	/* C: width of input surface*/