DISPLAY_PLANE_ENABLE
WARN_ON(I915_READ(DSPCNTR(PLANE_A)) & DISPLAY_PLANE_ENABLE);
WARN_ON(I915_READ(DSPCNTR(PLANE_B)) & DISPLAY_PLANE_ENABLE);
WARN_ON(I915_READ(DSPCNTR(PLANE_C)) & DISPLAY_PLANE_ENABLE);
dspcntr = DISPLAY_PLANE_ENABLE | DISPPLANE_GAMMA_ENABLE;
ret = val & DISPLAY_PLANE_ENABLE;