snd_unit2d
#define CHN_DEV(x) (snd_unit2d((x)->unit))
dtype = snd_unit2d(unit);
switch (snd_unit2d(devunit)) {
if (devunit == -1 || snd_unit2d(devunit) == SND_DEV_DSPHW_VPLAY ||
snd_unit2d(devunit) == SND_DEV_DSPHW_VREC) {