ttm_mem_reg_is_pci
bool ttm_mem_reg_is_pci(struct ttm_bo_device *bdev, struct ttm_mem_reg *mem);
bool old_is_pci = ttm_mem_reg_is_pci(bdev, &bo->mem);
bool new_is_pci = ttm_mem_reg_is_pci(bdev, mem);