[PATCH] backlight users need to select BACKLIGHT_CLASS_DEVICE

[Andy Whitcroft <apw@shadowen.org>]

I seem to have a similar issue, but with ACPI_TOSHIBA=y.  It does not
look like the backlight support is intended to be optional.  I also
note that ACPI_SONY is already select'ing BACKLIGHT_CLASS_DEVICE
directly.

The attached patch seems like the right thing.  I have tested this
with the config I had showing the problem.  My kernels now compile
again.

Seems that this change comes in from the following patch:
  add-support-for-the-generic-backlight-device-to-the-toshiba-acpi-driver

Does this seem sane?

Holger?

-apw

=== 8< ===
backlight users need to select BACKLIGHT_CLASS_DEVICE

When compiling 2.6.19-rc2-mm1 we get the following link
failures:

  drivers/built-in.o(.init.text+0x3076): In function `toshiba_acpi_init':
    : undefined reference to `backlight_device_register'
  drivers/built-in.o(.exit.text+0x170): In function `toshiba_acpi_exit':
    : undefined reference to `backlight_device_unregister'

When we build an ACPI module which provides backlight
support we need to ensure that the backlight class
device is selected.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
---
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 335da3e..819331d 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -179,7 +179,7 @@ config ACPI_NUMA
 config ACPI_ASUS
         tristate "ASUS/Medion Laptop Extras"
 	depends on X86
-	select BACKLIGHT_DEVICE
+	select BACKLIGHT_CLASS_DEVICE
         ---help---
           This driver provides support for extra features of ACPI-compatible
           ASUS laptops. As some of Medion laptops are made by ASUS, it may also
@@ -208,7 +208,7 @@ config ACPI_ASUS
 config ACPI_IBM
 	tristate "IBM ThinkPad Laptop Extras"
 	depends on X86
-	select BACKLIGHT_DEVICE
+	select BACKLIGHT_CLASS_DEVICE
 	---help---
 	  This is a Linux ACPI driver for the IBM ThinkPad laptops. It adds
 	  support for Fn-Fx key combinations, Bluetooth control, video
@@ -234,7 +234,7 @@ config ACPI_IBM_DOCK
 config ACPI_TOSHIBA
 	tristate "Toshiba Laptop Extras"
 	depends on X86
-	select BACKLIGHT_DEVICE
+	select BACKLIGHT_CLASS_DEVICE
 	---help---
 	  This driver adds support for access to certain system settings
 	  on "legacy free" Toshiba laptops.  These laptops can be recognized by