Trying to build the tip of the Git drm code (master branch plus against 2.6.30-rc5, I get some compile failures.

1.
=====
In file included from drm/linux-core/drmP.h:84, 
                 from drm/linux-core/drm_drawable.c:38: 
drm/linux-core/drm_os_linux.h:36: error: conflicting types for 'irqreturn_t'
include/linux/irqreturn.h:16: error: previous declaration of 'irqreturn_t' was here
make[2]: *** [drm/linux-core/drm_drawable.o] Error 1
=====
I trivially commented it out, but probably need a better detection algorithm for older kernels where it might still be needed.

2.
=====
  CC [M]  drm/linux-core/drm_sysfs.o
drm/linux-core/drm_sysfs.c: In function 'drm_sysfs_device_add':
drm/linux-core/drm_sysfs.c:172: error: 'struct device' has no member named 'bus_id'
=====
The bus_id member is totally gone. The drm_sysfs.c code in 2.6.30-rc5 has it fixed up,