Since we now subclass struct drm_device, we can save pointer dances by
noting the equivalence of struct drm_device and struct drm_i915_private,
i.e. by using to_i915().
text data bss dec hex filename 1073824 4562 416 1078802 107612 drivers/gpu/drm/i915/i915.ko 1068976 4562 416 1073954 106322 drivers/gpu/drm/i915/i915.ko