else
                i915_enable_pipestat(dev_priv, pipe,
                                     PIPE_VBLANK_INTERRUPT_STATUS);
-
-       /* maintain vblank delivery even in deep C-states */
-       if (INTEL_INFO(dev)->gen == 3)
-               I915_WRITE(INSTPM, _MASKED_BIT_DISABLE(INSTPM_AGPBUSY_DIS));
        spin_unlock_irqrestore(&dev_priv->irq_lock, irqflags);
 
        return 0;
        unsigned long irqflags;
 
        spin_lock_irqsave(&dev_priv->irq_lock, irqflags);
-       if (INTEL_INFO(dev)->gen == 3)
-               I915_WRITE(INSTPM, _MASKED_BIT_ENABLE(INSTPM_AGPBUSY_DIS));
-
        i915_disable_pipestat(dev_priv, pipe,
                              PIPE_VBLANK_INTERRUPT_STATUS |
                              PIPE_START_VBLANK_INTERRUPT_STATUS);
 
 
        /* IIR "flip pending" means done if this bit is set */
        I915_WRITE(ECOSKPD, _MASKED_BIT_DISABLE(ECO_FLIP_DONE));
+
+       /* interrupts should cause a wake up from C3 */
+       I915_WRITE(INSTPM, _MASKED_BIT_DISABLE(INSTPM_AGPBUSY_DIS));
 }
 
 static void i85x_init_clock_gating(struct drm_device *dev)