The comments under "config STUB_POULSBO" are close to correct,
but they are not being followed.  This patch updates them to reflect
the requirements for THERMAL.

This build error is caused by STUB_POULSBO selecting ACPI_VIDEO
when ACPI_VIDEO's config requirements are not met.

ERROR: "thermal_cooling_device_register" [drivers/acpi/video.ko] undefined!
ERROR: "thermal_cooling_device_unregister" [drivers/acpi/video.ko] undefined!
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Tested-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Remove the ACPI video output switching control as it never works.

With the patch applied,
ACPI video driver still catches the video output notification,
but it does nothing but raises the notification to userspace.
Signed-off-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

* Dave Airlie <airlied@linux.ie> wrote:

> > Lee, Chun-Yi (1):
> >       gpu: Add Intel GMA500(Poulsbo) Stub Driver

Today's -tip fails to build due to upstream commit e26fd119 ("gpu: Add Intel
GMA500(Poulsbo) Stub Driver"), committed two days ago and merged yesterday, on
x86 allmodconfig with BACKLIGHT_CLASS_DEVICE disabled:

 drivers/built-in.o: In function `acpi_video_bus_put_one_device':
 video.c:(.text+0x7d26f): undefined reference to `backlight_device_unregister'
 drivers/built-in.o: In function `acpi_video_switch_brightness':
 video.c:(.text+0x7d6f5): undefined reference to `backlight_force_update'
 drivers/built-in.o: In function `acpi_video_device_find_cap':
 video.c:(.text+0x7dfdb): undefined reference to `backlight_device_register'

drivers/gpu/stub/Kconfig selects ACPI_VIDEO, but ACPI_VIDEO is a complex interactive
Kconfig option with a lot of dependencies:

 config ACPI_VIDEO
	tristate "Video"
	depends on X86 && BACKLIGHT_CLASS_DEVICE && VIDEO_OUTPUT_CONTROL
	depends on INPUT
	select THERMAL
	help
	  This driver implements the ACPI Extensions For Display Adapters

and if any of its dependencies are not met, we get a build failure. This problem was
apparently realized in the driver at a certain stage:

 config STUB_POULSBO
        tristate "Intel GMA500 Stub Driver"
        depends on PCI
        # Poulsbo stub depends on ACPI_VIDEO when ACPI is enabled
        # but for select to work, need to select ACPI_VIDEO's dependencies, ick
        select ACPI_VIDEO if ACPI

but not fully understood and not fully fixed.

As a quick fix select these secondary dependencies, like drivers/gpu/drm/Kconfig
does:

 config DRM_I915
	tristate "i915 driver"
	depends on AGP_INTEL
	select SHMEM
	select DRM_KMS_HELPER
	select FB_CFB_FILLRECT
	select FB_CFB_COPYAREA
	select FB_CFB_IMAGEBLIT
	# i915 depends on ACPI_VIDEO when ACPI is enabled
	# but for select to work, need to select ACPI_VIDEO's dependencies, ick
	select VIDEO_OUTPUT_CONTROL if ACPI
	select BACKLIGHT_CLASS_DEVICE if ACPI
	select INPUT if ACPI
	select ACPI_VIDEO if ACPI
	select ACPI_BUTTON if ACPI
	help
	  Choose this option if you have a system that has Intel 830M, 845G,
	  852GM, 855GM 865G or 915G integrated graphics.  If M is selected, the

But it's arguably not particularly nice looking, so maybe this area of code is ripe
for a Kconfig restructuring/cleanup.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NDave Airlie <airlied@redhat.com>

Currently, there have no GMA500(Poulsbo) native video driver to support
intel opregion. So, use this stub driver to enable the acpi backlight
control sysfs entry files by requrest acpi_video_register.

[airlied: fix warnings]
Signed-off-by: NLee, Chun-Yi <jlee@novell.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>