diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/misc/thinkpad_acpi.c | 39 |
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) { |