SB_DSP_STEREO_SW
mixreg = snd_sbmixer_read(chip, SB_DSP_STEREO_SW);
snd_sbmixer_write(chip, SB_DSP_STEREO_SW, mixreg | 0x02);
snd_sbmixer_write(chip, SB_DSP_STEREO_SW, chip->force_mode16 & ~0x02);