PIPE_DATA_M_G4X
I915_WRITE(PIPE_DATA_M_G4X(pipe), TU_SIZE(m_n->tu) | m_n->gmch_m);
m_n->gmch_m = I915_READ(PIPE_DATA_M_G4X(pipe))
m_n->tu = ((I915_READ(PIPE_DATA_M_G4X(pipe))