FBC_CONTROL
dev_priv->regfile.saveFBC_CONTROL = I915_READ(FBC_CONTROL);
I915_WRITE(FBC_CONTROL, dev_priv->regfile.saveFBC_CONTROL);
fbc_ctl = I915_READ(FBC_CONTROL);
I915_WRITE(FBC_CONTROL, fbc_ctl);
I915_WRITE(FBC_CONTROL, 500 << FBC_CTL_INTERVAL_SHIFT);
fbc_ctl = I915_READ(FBC_CONTROL);
I915_WRITE(FBC_CONTROL, fbc_ctl);
return I915_READ(FBC_CONTROL) & FBC_CTL_EN;