pIn (PVOID)
Pointer to an allocate or register packet.
If the ulFunction field of the VRAMIN structure is set to
VRAM_ALLOCATE, VRAM_DEALLOCATE, or VRAM_QUERY, then pIn points to a
VRAMALLOCIN data structure.
If the ulFunction field of the VRAMIN structure is set to
VRAM_REGISTER or VRAM_DEGISTER, then pIn points to a VRAMREGISTERIN
data structure.