Drivers that need to allocate large chunks of memory need to make special arrangements, especially if that memory must be physically contiguous. The memory must be allocated very early in the system start-up process or it is unlikely that large chunks of physically contiguous memory will be available.
DDI drivers that allocate large chunks of memory should be statically configured, or split into two drivers:
All ODDI drivers are statically configured, so can allocate large chunks of physically contiguous memory in their init(D2oddi) or start(D2oddi) routines.
For information about supporting large driver mappings,