drm/i915: emit a hotplug event on resume

This will poke userspace into probing for configuration changes that may
have occurred across suspend/resume.
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -545,6 +545,24 @@ void intel_console_resume(struct work_struct *work)
 	console_unlock();
 }
 
+static void intel_resume_hotplug(struct drm_device *dev)
+{
+	struct drm_mode_config *mode_config = &dev->mode_config;
+	struct intel_encoder *encoder;
+
+	mutex_lock(&mode_config->mutex);
+	DRM_DEBUG_KMS("running encoder hotplug functions\n");
+
+	list_for_each_entry(encoder, &mode_config->encoder_list, base.head)
+		if (encoder->hot_plug)
+			encoder->hot_plug(encoder);
+
+	mutex_unlock(&mode_config->mutex);
+
+	/* Just fire off a uevent and let userspace tell us what to do */
+	drm_helper_hpd_irq_event(dev);
+}
+
 static int __i915_drm_thaw(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -580,6 +598,8 @@ static int __i915_drm_thaw(struct drm_device *dev)
 		 * */
 		intel_hpd_init(dev);
 		dev_priv->enable_hotplug_processing = true;
+		/* Config may have changed between suspend and resume */
+		intel_resume_hotplug(dev);
 	}
 
 	intel_opregion_init(dev);