GPMODE_AUDIO_CTL_PAGE
ret = cdrom_mode_sense(cdi, cgc, GPMODE_AUDIO_CTL_PAGE, 0);
GPMODE_AUDIO_CTL_PAGE, 0);
if ((buffer[offset] & 0x3f) != GPMODE_AUDIO_CTL_PAGE ||
ret = cdrom_mode_sense(cdi, cgc, GPMODE_AUDIO_CTL_PAGE, 1);