drm git doesn't build against 2.6.21-rc1

make DRM_MODULES=i915.o modules
make[1]: Entering directory `/home/inst/drm/linux-core'
sh ../scripts/create_linux_pci_lists.sh < ../shared-core/drm_pciids.txt
make -C /lib/modules/2.6.21-0224/source  SUBDIRS=`pwd` DRMSRCDIR=`pwd` modules
make[2]: Entering directory `/usr/src/linux-2.6.20'
  CC [M]  /home/inst/drm/linux-core/drm_auth.o
  CC [M]  /home/inst/drm/linux-core/drm_bufs.o
  CC [M]  /home/inst/drm/linux-core/drm_context.o
  CC [M]  /home/inst/drm/linux-core/drm_dma.o
  CC [M]  /home/inst/drm/linux-core/drm_drawable.o
  CC [M]  /home/inst/drm/linux-core/drm_drv.o
include/linux/pci.h: In function `drm_init':
/home/inst/drm/linux-core/drm_drv.c:333: warning: ignoring return value of `pci_register_driver', declared with attribute warn_unused_result
  CC [M]  /home/inst/drm/linux-core/drm_fops.o
  CC [M]  /home/inst/drm/linux-core/drm_ioctl.o
  CC [M]  /home/inst/drm/linux-core/drm_irq.o
  CC [M]  /home/inst/drm/linux-core/drm_lock.o
  CC [M]  /home/inst/drm/linux-core/drm_memory.o
  CC [M]  /home/inst/drm/linux-core/drm_proc.o
  CC [M]  /home/inst/drm/linux-core/drm_stub.o
/home/inst/drm/linux-core/drm_stub.c: In function `drm_get_dev':
/home/inst/drm/linux-core/drm_stub.c:236: warning: ignoring return value of `pci_request_regions', declared with attribute warn_unused_result
/home/inst/drm/linux-core/drm_stub.c:239: warning: ignoring return value of `pci_enable_device', declared with attribute warn_unused_result
  CC [M]  /home/inst/drm/linux-core/drm_vm.o
/home/inst/drm/linux-core/drm_vm.c:740: warning: "struct fault_data" declared inside parameter list
/home/inst/drm/linux-core/drm_vm.c:740: warning: its scope is only this definition or declaration, which is probably not what you want
/home/inst/drm/linux-core/drm_vm.c: In function `drm_bo_vm_fault':
/home/inst/drm/linux-core/drm_vm.c:742: error: dereferencing pointer to incomplete type
/home/inst/drm/linux-core/drm_vm.c:759: error: dereferencing pointer to incomplete type
/home/inst/drm/linux-core/drm_vm.c:796: error: dereferencing pointer to incomplete type
/home/inst/drm/linux-core/drm_vm.c:803: error: dereferencing pointer to incomplete type
/home/inst/drm/linux-core/drm_vm.c:812: error: dereferencing pointer to incomplete type
/home/inst/drm/linux-core/drm_vm.c:829: error: dereferencing pointer to incomplete type
/home/inst/drm/linux-core/drm_vm.c:839: error: dereferencing pointer to incomplete type
/home/inst/drm/linux-core/drm_vm.c:841: error: dereferencing pointer to incomplete type
/home/inst/drm/linux-core/drm_vm.c: At top level:
/home/inst/drm/linux-core/drm_vm.c:900: error: unknown field `fault' specified in initializer
/home/inst/drm/linux-core/drm_vm.c:900: warning: initialization from incompatible pointer type
make[3]: *** [/home/inst/drm/linux-core/drm_vm.o] Error 1
make[2]: *** [_module_/home/inst/drm/linux-core] Error 2
make[2]: Leaving directory `/usr/src/linux-2.6.20'
make[1]: *** [modules] Error 2
make[1]: Leaving directory `/home/inst/drm/linux-core'
make: *** [i915.o] Error 2