atiixp_dma_desc_t
atiixp_dma_desc_t *caddr_v, *next_caddr_v;
bzero(caddr_v, sizeof(atiixp_dma_desc_t));
next_caddr_p = caddr_p + sizeof(atiixp_dma_desc_t);
error = auixp_allocmem(sc, DMA_DESC_CHAIN * sizeof(atiixp_dma_desc_t),