ACPI / video: Don't register acpi_video_resume notifier without backlight devices

If we're not going to be registering any backlight devices then
acpi_video_resume is always nop, so don't register it in that case.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index fced27d..ff79dff 100644 (file)
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -150,6 +150,7 @@ struct acpi_video_enumerated_device {
 
 struct acpi_video_bus {
        struct acpi_device *device;
+       bool backlight_registered;
        u8 dos_setting;
        struct acpi_video_enumerated_device *attached_array;
        u8 attached_count;
@@ -1666,88 +1667,89 @@ acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
 
 static void acpi_video_dev_register_backlight(struct acpi_video_device *device)
 {
-       if (acpi_video_verify_backlight_support()) {
-               struct backlight_properties props;
-               struct pci_dev *pdev;
-               acpi_handle acpi_parent;
-               struct device *parent = NULL;
-               int result;
-               static int count;
-               char *name;
-
-               result = acpi_video_init_brightness(device);
-               if (result)
-                       return;
-               name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
-               if (!name)
-                       return;
-               count++;
+       struct backlight_properties props;
+       struct pci_dev *pdev;
+       acpi_handle acpi_parent;
+       struct device *parent = NULL;
+       int result;
+       static int count;
+       char *name;
 
-               acpi_get_parent(device->dev->handle, &acpi_parent);
+       result = acpi_video_init_brightness(device);
+       if (result)
+               return;
+       name = kasprintf(GFP_KERNEL, "acpi_video%d", count);
+       if (!name)
+               return;
+       count++;
 
-               pdev = acpi_get_pci_dev(acpi_parent);
-               if (pdev) {
-                       parent = &pdev->dev;
-                       pci_dev_put(pdev);
-               }
+       acpi_get_parent(device->dev->handle, &acpi_parent);
 
-               memset(&props, 0, sizeof(struct backlight_properties));
-               props.type = BACKLIGHT_FIRMWARE;
-               props.max_brightness = device->brightness->count - 3;
-               device->backlight = backlight_device_register(name,
-                                                             parent,
-                                                             device,
-                                                             &acpi_backlight_ops,
-                                                             &props);
-               kfree(name);
-               if (IS_ERR(device->backlight))
-                       return;
+       pdev = acpi_get_pci_dev(acpi_parent);
+       if (pdev) {
+               parent = &pdev->dev;
+               pci_dev_put(pdev);
+       }
 
-               /*
-                * Save current brightness level in case we have to restore it
-                * before acpi_video_device_lcd_set_level() is called next time.
-                */
-               device->backlight->props.brightness =
-                               acpi_video_get_brightness(device->backlight);
+       memset(&props, 0, sizeof(struct backlight_properties));
+       props.type = BACKLIGHT_FIRMWARE;
+       props.max_brightness = device->brightness->count - 3;
+       device->backlight = backlight_device_register(name,
+                                                     parent,
+                                                     device,
+                                                     &acpi_backlight_ops,
+                                                     &props);
+       kfree(name);
+       if (IS_ERR(device->backlight))
+               return;
 
-               device->cooling_dev = thermal_cooling_device_register("LCD",
-                                       device->dev, &video_cooling_ops);
-               if (IS_ERR(device->cooling_dev)) {
-                       /*
-                        * Set cooling_dev to NULL so we don't crash trying to
-                        * free it.
-                        * Also, why the hell we are returning early and
-                        * not attempt to register video output if cooling
-                        * device registration failed?
-                        * -- dtor
-                        */
-                       device->cooling_dev = NULL;
-                       return;
-               }
+       /*
+        * Save current brightness level in case we have to restore it
+        * before acpi_video_device_lcd_set_level() is called next time.
+        */
+       device->backlight->props.brightness =
+                       acpi_video_get_brightness(device->backlight);
 
-               dev_info(&device->dev->dev, "registered as cooling_device%d\n",
-                        device->cooling_dev->id);
-               result = sysfs_create_link(&device->dev->dev.kobj,
-                               &device->cooling_dev->device.kobj,
-                               "thermal_cooling");
-               if (result)
-                       printk(KERN_ERR PREFIX "Create sysfs link\n");
-               result = sysfs_create_link(&device->cooling_dev->device.kobj,
-                               &device->dev->dev.kobj, "device");
-               if (result)
-                       printk(KERN_ERR PREFIX "Create sysfs link\n");
+       device->cooling_dev = thermal_cooling_device_register("LCD",
+                               device->dev, &video_cooling_ops);
+       if (IS_ERR(device->cooling_dev)) {
+               /*
+                * Set cooling_dev to NULL so we don't crash trying to free it.
+                * Also, why the hell we are returning early and not attempt to
+                * register video output if cooling device registration failed?
+                * -- dtor
+                */
+               device->cooling_dev = NULL;
+               return;
        }
+
+       dev_info(&device->dev->dev, "registered as cooling_device%d\n",
+                device->cooling_dev->id);
+       result = sysfs_create_link(&device->dev->dev.kobj,
+                       &device->cooling_dev->device.kobj,
+                       "thermal_cooling");
+       if (result)
+               printk(KERN_ERR PREFIX "Create sysfs link\n");
+       result = sysfs_create_link(&device->cooling_dev->device.kobj,
+                       &device->dev->dev.kobj, "device");
+       if (result)
+               printk(KERN_ERR PREFIX "Create sysfs link\n");
 }
 
 static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
 {
        struct acpi_video_device *dev;
 
+       if (!acpi_video_verify_backlight_support())
+               return 0;
+
        mutex_lock(&video->device_list_lock);
        list_for_each_entry(dev, &video->video_device_list, entry)
                acpi_video_dev_register_backlight(dev);
        mutex_unlock(&video->device_list_lock);
 
+       video->backlight_registered = true;
+
        video->pm_nb.notifier_call = acpi_video_resume;
        video->pm_nb.priority = 0;
        return register_pm_notifier(&video->pm_nb);
@@ -1775,13 +1777,20 @@ static void acpi_video_dev_unregister_backlight(struct acpi_video_device *device
 static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
 {
        struct acpi_video_device *dev;
-       int error = unregister_pm_notifier(&video->pm_nb);
+       int error;
+
+       if (!video->backlight_registered)
+               return 0;
+
+       error = unregister_pm_notifier(&video->pm_nb);
 
        mutex_lock(&video->device_list_lock);
        list_for_each_entry(dev, &video->video_device_list, entry)
                acpi_video_dev_unregister_backlight(dev);
        mutex_unlock(&video->device_list_lock);
 
+       video->backlight_registered = false;
+
        return error;
 }