4 files changed, 94 insertions, 9 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.
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index adb319b53ecd..cf188ab7051a 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1648,7 +1648,7 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
         if (INTEL_INFO(dev)->num_pipes) {
                 /* Must be done after probing outputs */
                 intel_opregion_init(dev);
-                acpi_video_register();
+                acpi_video_register_with_quirks();
         }
 
         if (IS_GEN5(dev))