int snd_usb_mixer_set_ctl_value(struct usb_mixer_elem_info *cval,
int request, int validx, int value_set);
+void snd_usb_mixer_inactivate(struct usb_mixer_interface *mixer);
+int snd_usb_mixer_activate(struct usb_mixer_interface *mixer);
#endif /* __USBMIXER_H */