[LAU] usb-audio-2.0 / class compliance question

[Florian Hanisch]

Dear all,

I already posted this question on other lists, so maybe one or the  
other has seen it, I apologize for sending it again.

I have been trying to connect a friend's soundcard (RME fireface UCX)
to my linux computer (recent ubuntu 12.04 installation - NOT ubuntu
studio, kernel 3.2.0-29-generic, ALSA version 1.0.25). RME claims that  
the device has a class compliance mode, so that it should be able to  
communicate with a linux system just using the USB-audio-2.0 standard  
(which, to my
knowledge, is available on linux). This class compliance mode works
when the device is connected to an apple computer.

Pluging the device, I get the following messages from dmesg:

[  864.024093] usb 1-1: new high-speed USB device number 5 using ehci_hcd
[  864.162776] usbaudio: unit 2: invalid UAC_FEATURE_UNIT descriptor
[  864.162831] snd-usb-audio: probe of 1-1:1.0 failed with error -5

The "lsusb - v" (quite lengthy, so I don't include it here) output  
lists the device, so it seems that it is recognized but can not be  
properly connected. It does not appear neither appear in the system  
settings nor in JACK.

Am I missing some extra packages, libaries, ... to be able to have
full USB-audio-2.0 support ? Do I have to change some kernel options ?
Any other ideas ?

Thanks,

Florian