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path: root/drivers/acpi/video.c
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Diffstat (limited to 'drivers/acpi/video.c')
-rw-r--r--drivers/acpi/video.c51
1 files changed, 50 insertions, 1 deletions
diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c
index 05dff631591..b765790b32b 100644
--- a/drivers/acpi/video.c
+++ b/drivers/acpi/video.c
@@ -78,6 +78,13 @@ MODULE_LICENSE("GPL");
static int brightness_switch_enabled = 1;
module_param(brightness_switch_enabled, bool, 0644);
+/*
+ * By default, we don't allow duplicate ACPI video bus devices
+ * under the same VGA controller
+ */
+static int allow_duplicates;
+module_param(allow_duplicates, bool, 0644);
+
static int register_count = 0;
static int acpi_video_bus_add(struct acpi_device *device);
static int acpi_video_bus_remove(struct acpi_device *device, int type);
@@ -999,8 +1006,10 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device)
sprintf(name, "acpi_video%d", count++);
device->backlight = backlight_device_register(name,
NULL, device, &acpi_backlight_ops);
- device->backlight->props.max_brightness = device->brightness->count-3;
kfree(name);
+ if (IS_ERR(device->backlight))
+ return;
+ device->backlight->props.max_brightness = device->brightness->count-3;
result = sysfs_create_link(&device->backlight->dev.kobj,
&device->dev->dev.kobj, "device");
@@ -1979,6 +1988,10 @@ 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())
+ return 0;
+
if (!device->brightness)
goto out;
@@ -2233,11 +2246,47 @@ static int acpi_video_resume(struct acpi_device *device)
return AE_OK;
}
+static acpi_status
+acpi_video_bus_match(acpi_handle handle, u32 level, void *context,
+ void **return_value)
+{
+ struct acpi_device *device = context;
+ struct acpi_device *sibling;
+ int result;
+
+ if (handle == device->handle)
+ return AE_CTRL_TERMINATE;
+
+ result = acpi_bus_get_device(handle, &sibling);
+ if (result)
+ return AE_OK;
+
+ if (!strcmp(acpi_device_name(sibling), ACPI_VIDEO_BUS_NAME))
+ return AE_ALREADY_EXISTS;
+
+ return AE_OK;
+}
+
static int acpi_video_bus_add(struct acpi_device *device)
{
struct acpi_video_bus *video;
struct input_dev *input;
int error;
+ acpi_status status;
+
+ status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
+ device->parent->handle, 1,
+ acpi_video_bus_match, NULL,
+ device, NULL);
+ if (status == AE_ALREADY_EXISTS) {
+ printk(KERN_WARNING FW_BUG
+ "Duplicate ACPI video bus devices for the"
+ " same VGA controller, please try module "
+ "parameter \"video.allow_duplicates=1\""
+ "if the current driver doesn't work.\n");
+ if (!allow_duplicates)
+ return -ENODEV;
+ }
video = kzalloc(sizeof(struct acpi_video_bus), GFP_KERNEL);
if (!video)