Merge branch 'acpi-video'

* acpi-video:
  ACPI / video: Add 4 new models to the use_native_backlight DMI list
  ACPI / video: Add use native backlight quirk for the ThinkPad W530
  ACPI / video: Unregister the backlight device if a raw one shows up later
  backlight: Add backlight device (un)registration notification
  nouveau: Don't check acpi_video_backlight_support() before registering backlight
  acer-wmi: Add Aspire 5741 to video_vendor_dmi_table
  acer-wmi: Switch to acpi_video_unregister_backlight
  ACPI / video: Add an acpi_video_unregister_backlight function
  ACPI / video: Don't register acpi_video_resume notifier without backlight devices
  ACPI / video: change acpi-video brightness_switch_enabled default to 0

Documentation/kernel-parameters.txt

@@ -3481,7 +3481,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			the allocated input device; If set to 0, video driver
 			will only send out the event without touching backlight
 			brightness level.
-			default: 1
+			default: 0
 
 	virtio_mmio.device=
 			[VMMIO] Memory mapped virtio (platform) device.

drivers/gpu/drm/nouveau/nouveau_backlight.c

@@ -31,7 +31,6 @@
  */
 
 #include <linux/backlight.h>
-#include <linux/acpi.h>
 
 #include "nouveau_drm.h"
 #include "nouveau_reg.h"
@@ -222,14 +221,6 @@ nouveau_backlight_init(struct drm_device *dev)
 	struct nouveau_device *device = nv_device(drm->device);
 	struct drm_connector *connector;
 
-#ifdef CONFIG_ACPI
-	if (acpi_video_backlight_support()) {
-		NV_INFO(drm, "ACPI backlight interface available, "
-			     "not registering our own\n");
-		return 0;
-	}
-#endif
-
 	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
 		if (connector->connector_type != DRM_MODE_CONNECTOR_LVDS &&
 		    connector->connector_type != DRM_MODE_CONNECTOR_eDP)

drivers/platform/x86/acer-wmi.c

@@ -570,6 +570,14 @@ static const struct dmi_system_id video_vendor_dmi_table[] = {
 			DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5750"),
 		},
 	},
+	{
+		.callback = video_set_backlight_video_vendor,
+		.ident = "Acer Aspire 5741",
+		.matches = {
+			DMI_MATCH(DMI_BOARD_VENDOR, "Acer"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 5741"),
+		},
+	},
 	{}
 };
 
@@ -2228,7 +2236,7 @@ static int __init acer_wmi_init(void)
 		pr_info("Brightness must be controlled by acpi video driver\n");
 	} else {
 		pr_info("Disabling ACPI video driver\n");
-		acpi_video_unregister();
+		acpi_video_unregister_backlight();
 	}
 
 	if (wmi_has_guid(WMID_GUID3)) {

drivers/video/backlight/backlight.c

@@ -23,6 +23,7 @@
 
 static struct list_head backlight_dev_list;
 static struct mutex backlight_dev_list_mutex;
+static struct blocking_notifier_head backlight_notifier;
 
 static const char *const backlight_types[] = {
 	[BACKLIGHT_RAW] = "raw",
@@ -370,6 +371,9 @@ struct backlight_device *backlight_device_register(const char *name,
 	list_add(&new_bd->entry, &backlight_dev_list);
 	mutex_unlock(&backlight_dev_list_mutex);
 
+	blocking_notifier_call_chain(&backlight_notifier,
+				     BACKLIGHT_REGISTERED, new_bd);
+
 	return new_bd;
 }
 EXPORT_SYMBOL(backlight_device_register);
@@ -413,6 +417,10 @@ void backlight_device_unregister(struct backlight_device *bd)
 		pmac_backlight = NULL;
 	mutex_unlock(&pmac_backlight_mutex);
 #endif
+
+	blocking_notifier_call_chain(&backlight_notifier,
+				     BACKLIGHT_UNREGISTERED, bd);
+
 	mutex_lock(&bd->ops_lock);
 	bd->ops = NULL;
 	mutex_unlock(&bd->ops_lock);
@@ -437,6 +445,36 @@ static int devm_backlight_device_match(struct device *dev, void *res,
 	return *r == data;
 }
 
+/**
+ * backlight_register_notifier - get notified of backlight (un)registration
+ * @nb: notifier block with the notifier to call on backlight (un)registration
+ *
+ * @return 0 on success, otherwise a negative error code
+ *
+ * Register a notifier to get notified when backlight devices get registered
+ * or unregistered.
+ */
+int backlight_register_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&backlight_notifier, nb);
+}
+EXPORT_SYMBOL(backlight_register_notifier);
+
+/**
+ * backlight_unregister_notifier - unregister a backlight notifier
+ * @nb: notifier block to unregister
+ *
+ * @return 0 on success, otherwise a negative error code
+ *
+ * Register a notifier to get notified when backlight devices get registered
+ * or unregistered.
+ */
+int backlight_unregister_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&backlight_notifier, nb);
+}
+EXPORT_SYMBOL(backlight_unregister_notifier);
+
 /**
  * devm_backlight_device_register - resource managed backlight_device_register()
  * @dev: the device to register
@@ -544,6 +582,8 @@ static int __init backlight_class_init(void)
 	backlight_class->pm = &backlight_class_dev_pm_ops;
 	INIT_LIST_HEAD(&backlight_dev_list);
 	mutex_init(&backlight_dev_list_mutex);
+	BLOCKING_INIT_NOTIFIER_HEAD(&backlight_notifier);
+
 	return 0;
 }
 

include/acpi/video.h

@@ -19,11 +19,13 @@ struct acpi_device;
 #if (defined CONFIG_ACPI_VIDEO || defined CONFIG_ACPI_VIDEO_MODULE)
 extern int acpi_video_register(void);
 extern void acpi_video_unregister(void);
+extern void acpi_video_unregister_backlight(void);
 extern int acpi_video_get_edid(struct acpi_device *device, int type,
 			       int device_id, void **edid);
 #else
 static inline int acpi_video_register(void) { return 0; }
 static inline void acpi_video_unregister(void) { return; }
+static inline void acpi_video_unregister_backlight(void) { return; }
 static inline int acpi_video_get_edid(struct acpi_device *device, int type,
 				      int device_id, void **edid)
 {

include/linux/backlight.h

@@ -40,6 +40,11 @@ enum backlight_type {
 	BACKLIGHT_TYPE_MAX,
 };
 
+enum backlight_notification {
+	BACKLIGHT_REGISTERED,
+	BACKLIGHT_UNREGISTERED,
+};
+
 struct backlight_device;
 struct fb_info;
 
@@ -133,6 +138,8 @@ extern void devm_backlight_device_unregister(struct device *dev,
 extern void backlight_force_update(struct backlight_device *bd,
 				   enum backlight_update_reason reason);
 extern bool backlight_device_registered(enum backlight_type type);
+extern int backlight_register_notifier(struct notifier_block *nb);
+extern int backlight_unregister_notifier(struct notifier_block *nb);
 
 #define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)