gma_enable_pipestat
gma_enable_pipestat(dev_priv, 0, PIPE_LEGACY_BLC_EVENT_ENABLE);
gma_enable_pipestat(dev_priv, 1, PIPE_LEGACY_BLC_EVENT_ENABLE);
gma_enable_pipestat(dev_priv, i, PIPE_VBLANK_INTERRUPT_ENABLE);
gma_enable_pipestat(dev_priv, pipe, PIPE_VBLANK_INTERRUPT_ENABLE);
void gma_enable_pipestat(struct drm_psb_private *dev_priv, int pipe, u32 mask);