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Commit 056c308d authored by Zhang Rui's avatar Zhang Rui Committed by Len Brown
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Show the physical device node of backlight class device. 



Create symbol link from backlight class device to ACPI video device.

More and more laptops are shipped with multiple ACPI
video devices, while we export only one of them to userspace.

With this patch applied, we can know which ACPI video device
is used by "cat /sys/class/backlight/acpi_video0/device/path".

Signed-off-by: default avatarZhang Rui <rui.zhang@intel.com>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent 07a2039b

drivers/acpi/video.c

+6 −0
Original line number Diff line number Diff line
@@ -976,6 +976,11 @@ static void acpi_video_device_find_cap(struct acpi_video_device *device) 
		device->backlight->props.max_brightness = device->brightness->count-3;

		kfree(name);



		result = sysfs_create_link(&device->backlight->dev.kobj,

					   &device->dev->dev.kobj, "device");

		if (result)

			printk(KERN_ERR PREFIX "Create sysfs link\n");



		device->cdev = thermal_cooling_device_register("LCD",

					device->dev, &video_cooling_ops);

		if (IS_ERR(device->cdev))
@@ -1990,6 +1995,7 @@ static int acpi_video_bus_put_one_device(struct acpi_video_device *device) 
	status = acpi_remove_notify_handler(device->dev->handle,

					    ACPI_DEVICE_NOTIFY,

					    acpi_video_device_notify);

	sysfs_remove_link(&device->backlight->dev.kobj, "device");

	backlight_device_unregister(device->backlight);

	if (device->cdev) {

		sysfs_remove_link(&device->dev->dev.kobj,