diff --git a/src/backends/x11/common/eglonxbackend.cpp b/src/backends/x11/common/eglonxbackend.cpp
index c57129750b..00fbcdd00d 100644
--- a/src/backends/x11/common/eglonxbackend.cpp
+++ b/src/backends/x11/common/eglonxbackend.cpp
@@ -225,7 +225,7 @@ EGLSurface EglOnXBackend::createSurface(xcb_window_t window)
         // a c style cast as there are (buggy) platforms where the size of the Window
         // type is not the same as the size of EGLNativeWindowType, reinterpret_cast<>()
         // may not compile.
-        surface = eglCreateWindowSurface(eglDisplay(), config(), (EGLNativeWindowType) nativeWindow, nullptr);
+        surface = eglCreateWindowSurface(eglDisplay(), config(), (EGLNativeWindowType)(uintptr_t)nativeWindow, nullptr);
     }
 
     return surface;
diff --git a/src/backends/x11/standalone/eglbackend.cpp b/src/backends/x11/standalone/eglbackend.cpp
index 99750d2d08..2173779829 100644
--- a/src/backends/x11/standalone/eglbackend.cpp
+++ b/src/backends/x11/standalone/eglbackend.cpp
@@ -228,8 +228,11 @@ bool EglPixmapTexturePrivate::create(SurfacePixmapX11 *pixmap)
         EGL_IMAGE_PRESERVED_KHR, EGL_TRUE,
         EGL_NONE
     };
-    m_image = eglCreateImageKHR(m_backend->eglDisplay(), EGL_NO_CONTEXT, EGL_NATIVE_PIXMAP_KHR,
-                                reinterpret_cast<EGLClientBuffer>(nativePixmap), attribs);
+    m_image = eglCreateImageKHR(m_backend->eglDisplay(),
+                                EGL_NO_CONTEXT,
+                                EGL_NATIVE_PIXMAP_KHR,
+                                reinterpret_cast<EGLClientBuffer>(static_cast<uintptr_t>(nativePixmap)),
+                                attribs);
 
     if (EGL_NO_IMAGE_KHR == m_image) {
         qCDebug(KWIN_CORE) << "failed to create egl image";