iPod Nano (2nd) USB fun...
I just stumbled over that, and it seems that nobody else did yet (at least, I couldn’t find anything on google):
Bus 001 Device 007: ID 05ac:1260 Apple Computer, Inc.
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x05ac Apple Computer, Inc.
idProduct 0x1260
bcdDevice 0.02
iManufacturer 1 Apple
iProduct 2
iSerial 3 000A2700188443C7
bNumConfigurations 2
Configuration Descriptor:
[…]
Interface Descriptor:
[…]
bInterfaceClass 8 Mass Storage
[…]
Configuration Descriptor:
[…]
iConfiguration 4 iPod USB Interface
Interface Descriptor:
[…]
bInterfaceClass 1 Audio
[…]
AudioControl Interface Descriptor:
[…]
wTerminalType 0x0201 Microphone
[…]
bDescriptorSubtype 3 (OUTPUT_TERMINAL)
wTerminalType 0x0101 USB Streaming
[…]
Interface Descriptor:
[…]
bInterfaceClass 3 Human Interface Devices
It really looks like the iPod is exposing its Audio interface (and possibly the keys?) over USB as an alternate configuration. The linux snd-usb-sound didn’t worked out-of-the-box, so further investigation is required.