diff --git a/effects/screenshot/screenshot.cpp b/effects/screenshot/screenshot.cpp
index b66013d417..8390716b71 100644
--- a/effects/screenshot/screenshot.cpp
+++ b/effects/screenshot/screenshot.cpp
@@ -141,7 +141,7 @@ void ScreenShotEffect::postPaintScreen()
                 restoreMatrix();
                 // copy content from framebuffer into image
                 img = QImage(QSize(width, height), QImage::Format_ARGB32);
-                glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, (GLvoid*)img.bits());
+                glReadnPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, img.byteCount(), (GLvoid*)img.bits());
                 GLRenderTarget::popRenderTarget();
                 ScreenShotEffect::convertFromGLImage(img, width, height);
             }
diff --git a/libkwineffects/kwinglutils.cpp b/libkwineffects/kwinglutils.cpp
index ce6744d496..02a8b36119 100644
--- a/libkwineffects/kwinglutils.cpp
+++ b/libkwineffects/kwinglutils.cpp
@@ -649,7 +649,7 @@ QMatrix4x4 GLShader::getUniformMatrix4x4(const char* name)
     int location = uniformLocation(name);
     if (location >= 0) {
         GLfloat m[16];
-        glGetUniformfv(mProgram, location, m);
+        glGetnUniformfv(mProgram, location, sizeof(m), m);
         QMatrix4x4 matrix(m[0], m[4], m[8],  m[12],
                           m[1], m[5], m[9],  m[13],
                           m[2], m[6], m[10], m[14],