--- a/src/VBox/Additions/linux/drm/Makefile.module.kms
+++ b/src/VBox/Additions/linux/drm/Makefile.module.kms
@@ -43,7 +43,7 @@ else
  MANGLING := $(KBUILD_EXTMOD)/include/VBox/VBoxGuestMangling.h
 endif
 MOD_CFLAGS = -Wno-declaration-after-statement -fshort-wchar -include $(MANGLING) -fno-pie
-MOD_INCL   = $(addprefix -I$(KBUILD_EXTMOD),/ /include)
+MOD_INCL   = $(addprefix -I$(KBUILD_EXTMOD),/ /include /r0drv/linux)
 # What on earth is this?
 MOD_INCL  += $(addprefix -I$(KBUILD_EXTMOD)/vboxvideo,/ /include)
 MOD_INCL  += -Iinclude/drm