drm/i915: Only request PM interrupts for the events we handled

There is little point waking up every 10ms to service an interrupt which
we then promptly ignore. So only program the the PMIER to enable
interrupts for those events which we do handle, not all of them!
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Eugeni Dodonov <eugeni.dodonov@intel.com>
Cc: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_pm.c

@@ -2491,14 +2491,7 @@ static void gen6_enable_rps(struct drm_device *dev)
 	gen6_set_rps(dev_priv->dev, (gt_perf_status & 0xff00) >> 8);
 
 	/* requires MSI enabled */
-	I915_WRITE(GEN6_PMIER,
-		   GEN6_PM_MBOX_EVENT |
-		   GEN6_PM_THERMAL_EVENT |
-		   GEN6_PM_RP_DOWN_TIMEOUT |
-		   GEN6_PM_RP_UP_THRESHOLD |
-		   GEN6_PM_RP_DOWN_THRESHOLD |
-		   GEN6_PM_RP_UP_EI_EXPIRED |
-		   GEN6_PM_RP_DOWN_EI_EXPIRED);
+	I915_WRITE(GEN6_PMIER, GEN6_PM_DEFERRED_EVENTS);
 	spin_lock_irq(&dev_priv->rps_lock);
 	WARN_ON(dev_priv->pm_iir != 0);
 	I915_WRITE(GEN6_PMIMR, 0);