1 files changed, 39 insertions, 0 deletions

diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c
index 56a21e6b80a9..109bd2750439 100644
--- a/drivers/misc/thinkpad_acpi.c
+++ b/drivers/misc/thinkpad_acpi.c
@@ -3174,6 +3174,39 @@ static int __init brightness_check_levels(void)
         return (ACPI_SUCCESS(status) && found_node != NULL);
 }
 
+static acpi_status __init brightness_find_bcl(acpi_handle handle, u32 lvl,
+                                        void *context, void **rv)
+{
+        char name[ACPI_PATH_SEGMENT_LENGTH];
+        struct acpi_buffer buffer = { sizeof(name), &name };
+
+        if (ACPI_SUCCESS(acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer)) &&
+            !strncmp("_BCL", name, sizeof(name) - 1)) {
+                *rv = handle;
+                return AE_CTRL_TERMINATE;
+        } else {
+                return AE_OK;
+        }
+}
+
+static int __init brightness_check_std_acpi_support(void)
+{
+        int status;
+        void *found_node = NULL;
+
+        if (!vid_handle) {
+                IBM_ACPIHANDLE_INIT(vid);
+        }
+        if (!vid_handle)
+                return 0;
+
+        /* Search for a _BCL method, but don't execute it */
+        status = acpi_walk_namespace(ACPI_TYPE_METHOD, vid_handle, 3,
+                                     brightness_find_bcl, NULL, &found_node);
+
+        return (ACPI_SUCCESS(status) && found_node != NULL);
+}
+
 static int __init brightness_init(struct ibm_init_struct *iibm)
 {
         int b;
@@ -3186,6 +3219,12 @@ static int __init brightness_init(struct ibm_init_struct *iibm)
                 dbg_printk(TPACPI_DBG_INIT,
                            "brightness support disabled by module parameter\n");
                 return 1;
+        } else if (brightness_enable > 1) {
+                if (brightness_check_std_acpi_support()) {
+                        printk(IBM_NOTICE
+                               "standard ACPI backlight interface available, not loading native one...\n");
+                        return 1;
+                }
         }
 
         if (!brightness_mode) {