From 056c308d3e4859334b519033d62ef050f0e0e261 Mon Sep 17 00:00:00 2001 From: Zhang Rui Date: Mon, 22 Jun 2009 11:31:14 +0800 Subject: 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: Zhang Rui Signed-off-by: Len Brown --- drivers/acpi/video.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'drivers/acpi') diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index 1bdfb37377e..9de143af362 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -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, -- cgit v1.2.3