Comment 27 for bug 936539

have you ask the author of that patch ?

similar case is the four channel mic array of ps3 eye

USB Mixer information
!!---------------------------

USB Mixer: usb_id=0x14152000, ctrlif=1, ctlerr=0
Card: OmniVision Technologies, Inc. USB Camera-B4.04.27.1 at usb-0000:00:1d.7-4, high
  Unit: 3
    Control: name="Mic Capture Volume", index=0
    Info: id=3, control=2, cmask=0xf, channels=4, type="S16"
    Volume: min=0, max=1, dBmin=0, dBmax=0

https://www.libreoffice.org/bugzilla/show_bug.cgi?id=45813