drm/i915: leave rc6 enabled at suspend time v4

This allows the system to enter the lowest power mode during system freeze.

v2: delete force wake timer at suspend (Imre)
v3: add GT work suspend function (Imre)
v4: use uncore forcewake reset (Daniel)
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -529,7 +529,7 @@ static int i915_drm_freeze(struct drm_device *dev)
 		drm_irq_uninstall(dev);
 		dev_priv->enable_hotplug_processing = false;
 
-		intel_disable_gt_powersave(dev);
+		intel_suspend_gt_powersave(dev);
 
 		/*
 		 * Disable CRTCs directly since we want to preserve sw state
@@ -548,8 +548,8 @@ static int i915_drm_freeze(struct drm_device *dev)
 
 	i915_save_state(dev);
 
+	intel_uncore_forcewake_reset(dev, false);
 	intel_opregion_fini(dev);
-	intel_uncore_fini(dev);
 
 	console_lock();
 	intel_fbdev_set_suspend(dev, FBINFO_STATE_SUSPENDED);

drivers/gpu/drm/i915/i915_drv.h

@@ -2085,6 +2085,7 @@ extern void intel_uncore_early_sanitize(struct drm_device *dev);
 extern void intel_uncore_init(struct drm_device *dev);
 extern void intel_uncore_check_errors(struct drm_device *dev);
 extern void intel_uncore_fini(struct drm_device *dev);
+extern void intel_uncore_forcewake_reset(struct drm_device *dev, bool restore);
 
 void
 i915_enable_pipestat(struct drm_i915_private *dev_priv, enum pipe pipe,

drivers/gpu/drm/i915/intel_drv.h

@@ -961,6 +961,7 @@ void intel_init_gt_powersave(struct drm_device *dev);
 void intel_cleanup_gt_powersave(struct drm_device *dev);
 void intel_enable_gt_powersave(struct drm_device *dev);
 void intel_disable_gt_powersave(struct drm_device *dev);
+void intel_suspend_gt_powersave(struct drm_device *dev);
 void intel_reset_gt_powersave(struct drm_device *dev);
 void ironlake_teardown_rc6(struct drm_device *dev);
 void gen6_update_ring_freq(struct drm_device *dev);

drivers/gpu/drm/i915/intel_pm.c

@@ -4675,6 +4675,26 @@ void intel_cleanup_gt_powersave(struct drm_device *dev)
 		valleyview_cleanup_gt_powersave(dev);
 }
 
+/**
+ * intel_suspend_gt_powersave - suspend PM work and helper threads
+ * @dev: drm device
+ *
+ * We don't want to disable RC6 or other features here, we just want
+ * to make sure any work we've queued has finished and won't bother
+ * us while we're suspended.
+ */
+void intel_suspend_gt_powersave(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	/* Interrupts should be disabled already to avoid re-arming. */
+	WARN_ON(dev->irq_enabled);
+
+	flush_delayed_work(&dev_priv->rps.delayed_resume_work);
+
+	cancel_work_sync(&dev_priv->rps.work);
+}
+
 void intel_disable_gt_powersave(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;

drivers/gpu/drm/i915/intel_uncore.c

@@ -315,7 +315,7 @@ static void gen6_force_wake_timer(unsigned long arg)
 	intel_runtime_pm_put(dev_priv);
 }
 
-static void intel_uncore_forcewake_reset(struct drm_device *dev, bool restore)
+void intel_uncore_forcewake_reset(struct drm_device *dev, bool restore)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	unsigned long irqflags;