I have the same problem, but the hardware for the audio is not recognized, so I can not go to configure the device. It doesn't exist. From dmesg after connecting:
[420740.288084] usb 2-4: new high speed USB device using ehci_hcd and address 5
[420740.637295] uvcvideo: Found UVC 1.00 device <unnamed> (046d:0825)
[420740.733957] input: UVC Camera (046d:0825) as /devices/pci0000:00/0000:00:1d.7/usb2/2-4/2-4:1.0/input/input14
Anyone have any ideas? I'd love for my C270 to have audio.
Bus 002 Device 005: ID 046d:0825 Logitech, Inc.