drm/i915: Unconditionally initialise the interrupt workers

Rather than duplicate similar code across the IRQ installers, perform
the initialisation of the workers upfront. This will lead to simpler
teardown and quiescent code as we can assume that the workers have
been initialised.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_irq.c

@@ -2004,10 +2004,6 @@ static void ironlake_irq_preinstall(struct drm_device *dev)
 
 	atomic_set(&dev_priv->irq_received, 0);
 
-	INIT_WORK(&dev_priv->hotplug_work, i915_hotplug_work_func);
-	INIT_WORK(&dev_priv->error_work, i915_error_work_func);
-	if (IS_GEN6(dev) || IS_IVYBRIDGE(dev))
-		INIT_WORK(&dev_priv->rps_work, gen6_pm_rps_work);
 
 	I915_WRITE(HWSTAM, 0xeffe);
 
@@ -2035,9 +2031,6 @@ static void valleyview_irq_preinstall(struct drm_device *dev)
 
 	atomic_set(&dev_priv->irq_received, 0);
 
-	INIT_WORK(&dev_priv->hotplug_work, i915_hotplug_work_func);
-	INIT_WORK(&dev_priv->error_work, i915_error_work_func);
-
 	/* VLV magic */
 	I915_WRITE(VLV_IMR, 0);
 	I915_WRITE(RING_IMR(RENDER_RING_BASE), 0);
@@ -2306,9 +2299,6 @@ static void i915_driver_irq_preinstall(struct drm_device * dev)
 
 	atomic_set(&dev_priv->irq_received, 0);
 
-	INIT_WORK(&dev_priv->hotplug_work, i915_hotplug_work_func);
-	INIT_WORK(&dev_priv->error_work, i915_error_work_func);
-
 	if (I915_HAS_HOTPLUG(dev)) {
 		I915_WRITE(PORT_HOTPLUG_EN, 0);
 		I915_WRITE(PORT_HOTPLUG_STAT, I915_READ(PORT_HOTPLUG_STAT));
@@ -2625,6 +2615,12 @@ static void i8xx_irq_uninstall(struct drm_device * dev)
 
 void intel_irq_init(struct drm_device *dev)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	INIT_WORK(&dev_priv->hotplug_work, i915_hotplug_work_func);
+	INIT_WORK(&dev_priv->error_work, i915_error_work_func);
+	INIT_WORK(&dev_priv->rps_work, gen6_pm_rps_work);
+
 	dev->driver->get_vblank_counter = i915_get_vblank_counter;
 	dev->max_vblank_count = 0xffffff; /* only 24 bits of frame count */
 	if (IS_G4X(dev) || IS_GEN5(dev) || IS_GEN6(dev) || IS_IVYBRIDGE(dev) ||