HDA_DMA_ALIGNMENT
blksz -= blksz % lcm(HDA_DMA_ALIGNMENT, ch->b->align);
HDA_DMA_ALIGNMENT, /* alignment */
roundsz = roundup2(size, HDA_DMA_ALIGNMENT);
HDA_DMA_ALIGNMENT, /* alignment */
#define HDA_BLK_MIN HDA_DMA_ALIGNMENT