+static int __init tpacpi_query_bcll_levels(acpi_handle handle)
+{
+ struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+ union acpi_object *obj;
+ int rc;
+
+ if (ACPI_SUCCESS(acpi_evaluate_object(handle, NULL, NULL, &buffer))) {
+ obj = (union acpi_object *)buffer.pointer;
+ if (!obj || (obj->type != ACPI_TYPE_PACKAGE)) {
+ printk(IBM_ERR "Unknown BCLL data, "
+ "please report this to %s\n", IBM_MAIL);
+ rc = 0;
+ } else {
+ rc = obj->package.count;
+ }
+ } else {
+ return 0;
+ }
+
+ kfree(buffer.pointer);
+ return rc;
+}
+
+static acpi_status __init brightness_find_bcll(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("BCLL", name, sizeof(name) - 1)) {
+ if (tpacpi_query_bcll_levels(handle) == 16) {
+ *rv = handle;
+ return AE_CTRL_TERMINATE;
+ } else {
+ return AE_OK;
+ }
+ } else {
+ return AE_OK;
+ }
+}
+
+static int __init brightness_check_levels(void)
+{
+ int status;
+ void *found_node = NULL;
+
+ if (!vid_handle) {
+ IBM_ACPIHANDLE_INIT(vid);
+ }
+ if (!vid_handle)
+ return 0;
+
+ /* Search for a BCLL package with 16 levels */
+ status = acpi_walk_namespace(ACPI_TYPE_PACKAGE, vid_handle, 3,
+ brightness_find_bcll, NULL, &found_node);
+
+ 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);
+}
+