SB_DSP4_DMASETUP
status = snd_sbmixer_read(p->chip, SB_DSP4_DMASETUP);
snd_sbmixer_write(chip, SB_DSP4_DMASETUP, dmareg);
realdma = snd_sbmixer_read(chip, SB_DSP4_DMASETUP);
snd_sbmixer_write(chip, SB_DSP4_DMASETUP, SB_DMASETUP_DMA0);