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>

1 files changed, 74 insertions, 65 deletions

diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index fced27d8e42f..ff79dff371fd 100644
--- 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;
 }