- ioctl AUDIO_GETFD/SETFD, AUDIO_GETCHAN/SETCHAN are obsoleted.
ossaudio is still using this, although I don't know if it's critical.
compat/ossaudio/ossaudio.c:779
case OSS_SNDCTL_DSP_SETDUPLEX:
idat = 1;
error = ioctlf(fp, AUDIO_SETFD, &idat);