3 files changed, 93 insertions, 8 deletions

diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 3a50a34fe176..227aca77ee1e 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -164,4 +164,15 @@ struct platform_device;
 int acpi_create_platform_device(struct acpi_device *adev,
 				const struct acpi_device_id *id);
 
+/*--------------------------------------------------------------------------
+					Video
+  -------------------------------------------------------------------------- */
+#if defined(CONFIG_ACPI_VIDEO) || defined(CONFIG_ACPI_VIDEO_MODULE)
+bool acpi_video_backlight_quirks(void);
+bool acpi_video_verify_backlight_support(void);
+#else
+static inline bool acpi_video_backlight_quirks(void) { return false; }
+static inline bool acpi_video_verify_backlight_support(void) { return false; }
+#endif
+
 #endif /* _ACPI_INTERNAL_H_ */
diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index f236e172d948..e9d4bb60c35c 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -44,6 +44,8 @@
 #include <linux/suspend.h>
 #include <acpi/video.h>
 
+#include "internal.h"
+
 #define PREFIX "ACPI: "
 
 #define ACPI_VIDEO_BUS_NAME		"Video Bus"
@@ -901,7 +903,7 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device)
 	if (acpi_video_init_brightness(device))
 		return;
 
-	if (acpi_video_backlight_support()) {
+	if (acpi_video_verify_backlight_support()) {
 		struct backlight_properties props;
 		struct pci_dev *pdev;
 		acpi_handle acpi_parent;
@@ -1356,8 +1358,8 @@ acpi_video_switch_brightness(struct acpi_video_device *device, int event)
 	unsigned long long level_current, level_next;
 	int result = -EINVAL;
 
-	/* no warning message if acpi_backlight=vendor is used */
-	if (!acpi_video_backlight_support())
+	/* no warning message if acpi_backlight=vendor or a quirk is used */
+	if (!acpi_video_verify_backlight_support())
 		return 0;
 
 	if (!device->brightness)
@@ -1859,6 +1861,46 @@ static int acpi_video_bus_remove(struct acpi_device *device)
 	return 0;
 }
 
+static acpi_status video_unregister_backlight(acpi_handle handle, u32 lvl,
+					      void *context, void **rv)
+{
+	struct acpi_device *acpi_dev;
+	struct acpi_video_bus *video;
+	struct acpi_video_device *dev, *next;
+
+	if (acpi_bus_get_device(handle, &acpi_dev))
+		return AE_OK;
+
+	if (acpi_match_device_ids(acpi_dev, video_device_ids))
+		return AE_OK;
+
+	video = acpi_driver_data(acpi_dev);
+	if (!video)
+		return AE_OK;
+
+	acpi_video_bus_stop_devices(video);
+	mutex_lock(&video->device_list_lock);
+	list_for_each_entry_safe(dev, next, &video->video_device_list, entry) {
+		if (dev->backlight) {
+			backlight_device_unregister(dev->backlight);
+			dev->backlight = NULL;
+			kfree(dev->brightness->levels);
+			kfree(dev->brightness);
+		}
+		if (dev->cooling_dev) {
+			sysfs_remove_link(&dev->dev->dev.kobj,
+					  "thermal_cooling");
+			sysfs_remove_link(&dev->cooling_dev->device.kobj,
+					  "device");
+			thermal_cooling_device_unregister(dev->cooling_dev);
+			dev->cooling_dev = NULL;
+		}
+	}
+	mutex_unlock(&video->device_list_lock);
+	acpi_video_bus_start_devices(video);
+	return AE_OK;
+}
+
 static int __init is_i740(struct pci_dev *dev)
 {
 	if (dev->device == 0x00D1)
@@ -1890,14 +1932,25 @@ static int __init intel_opregion_present(void)
 	return opregion;
 }
 
-int acpi_video_register(void)
+int __acpi_video_register(bool backlight_quirks)
 {
-	int result = 0;
+	bool no_backlight;
+	int result;
+
+	no_backlight = backlight_quirks ? acpi_video_backlight_quirks() : false;
+
 	if (register_count) {
 		/*
-		 * if the function of acpi_video_register is already called,
-		 * don't register the acpi_vide_bus again and return no error.
+		 * If acpi_video_register() has been called already, don't try
+		 * to register acpi_video_bus, but unregister backlight devices
+		 * if no backlight support is requested.
 		 */
+		if (no_backlight)
+			acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
+					    ACPI_UINT32_MAX,
+					    video_unregister_backlight,
+					    NULL, NULL, NULL);
+
 		return 0;
 	}
 
@@ -1913,7 +1966,7 @@ int acpi_video_register(void)
 
 	return 0;
 }
-EXPORT_SYMBOL(acpi_video_register);
+EXPORT_SYMBOL(__acpi_video_register);
 
 void acpi_video_unregister(void)
 {
diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c
index e6bd910bc6ed..826e52def080 100644
--- a/drivers/acpi/video_detect.c
+++ b/drivers/acpi/video_detect.c
@@ -38,6 +38,8 @@
 #include <linux/dmi.h>
 #include <linux/pci.h>
 
+#include "internal.h"
+
 #define PREFIX "ACPI: "
 
 ACPI_MODULE_NAME("video");
@@ -234,6 +236,17 @@ static void acpi_video_caps_check(void)
 		acpi_video_get_capabilities(NULL);
 }
 
+bool acpi_video_backlight_quirks(void)
+{
+	if (acpi_gbl_osi_data >= ACPI_OSI_WIN_8) {
+		acpi_video_caps_check();
+		acpi_video_support |= ACPI_VIDEO_SKIP_BACKLIGHT;
+		return true;
+	}
+	return false;
+}
+EXPORT_SYMBOL(acpi_video_backlight_quirks);
+
 /* Promote the vendor interface instead of the generic video module.
  * This function allow DMI blacklists to be implemented by externals
  * platform drivers instead of putting a big blacklist in video_detect.c
@@ -278,6 +291,14 @@ int acpi_video_backlight_support(void)
 }
 EXPORT_SYMBOL(acpi_video_backlight_support);
 
+/* For the ACPI video driver use only. */
+bool acpi_video_verify_backlight_support(void)
+{
+	return (acpi_video_support & ACPI_VIDEO_SKIP_BACKLIGHT) ?
+		false : acpi_video_backlight_support();
+}
+EXPORT_SYMBOL(acpi_video_verify_backlight_support);
+
 /*
  * Use acpi_backlight=vendor/video to force that backlight switching
  * is processed by vendor specific acpi drivers or video.ko driver.