[i915] Kernel does not compile when set to use i915 kernel mode-setting per default (CONFIG_DRM_I915_KMS=y)

[Zorael <zorael@gmail.com>]

(First post, so please CC to zorael@gmail.com in case it doesn't automatically.)


I'm trying to compile 2.6.30-rc6 to enable kernel mode-setting *per
default*, for my Intel 945GME video chipset. Alas, when compiling, it
halts with the following tidbit:

...
  LD      .tmp_vmlinux1
drivers/built-in.o: In function `intel_opregion_free':
/usr/src/linux/drivers/gpu/drm/i915/i915_opregion.c:422: undefined
reference to `acpi_video_exit'
drivers/built-in.o: In function `intel_opregion_init':
/usr/src/linux/drivers/gpu/drm/i915/i915_opregion.c:393: undefined
reference to `acpi_video_register'
make[1]: *** [.tmp_vmlinux1] Error 1
make[1]: Leaving directory `/usr/src/linux-2.6.29'
make: *** [debian/stamp/build/kernel] Error 2


grepping acpi_video_register recursively I see it's defined as an
empty function in ./include/acpi/video.h, and as a more proper
function in ./drivers/acpi/video.c. Does somehow setting it to use KMS
per default via CONFIG_DRM_I915_KMS=y stop it from reading those
files?

I used to run with KMS by default in the early -30rc*s, but at some
point (rc2?), it stopped compiling succesfully. If I don't enable it
per default, it *does* compile, though I don't know how to explicitly
enable it at boot-time. So I'm living without KMS for the time being.
Woe.

Anything obvious I'm doing wrong?

-- Zorael