Re: USB Audio Passthrough

Gordan Bobic
Sun, 02 Jun 2013 10:10:12 -0000

On 06/02/2013 10:29 AM, Arjen wrote:
> On 02-06-13 11:06, Gordan Bobic wrote:
>> Hi,
>>
>> I''d like to ask if anyone managed to get USB audio passthrough
working?
>> In order to minimize PCI passthrough usage (I get audio dropouts on PCI
>> audio passthrough (Intel ICH audio) lasting 10-30 seconds every few
>> minutes), I got a generic USB audio adapter. It works fine on bare
metal
>> but in domU all I get is loud crackling noise instead of sound.
>>
>> Could this be related to Xen USB passthrough being limited to USB 1.1
>> and the USB audio possibly requiring more bandwidth than that?
>>
>> Has anyone got USB audio passthrough working successfully and reliably?
>> What USB sound module did you use?
>
> I worked around a possibly similar problem with built-in Intel HD audio
> by initializing it on the dom0 (instead of hiding it) before doing the
> PCI passthrough.

The odd thing is that it works fine initially, then at random intervals
every few minutes it will drop out completely and go silent, before
returning and continuing to work fine. If it was an initialization issue
I would have expected it to not work to begin with (or at all).



> Also got some helpful advice over USB audio before, see thread:
> http://lists.xen.org/archives/html/xen-users/2013-05/msg00166.html

As I said, I do have a generic (£3) USB audio adapter that works fine on
bare metal on 3 different machines, but when use with my domU, all I get
is loud crackling instead of sound. The crackling stops when the audio
playback stops, so I''m wondering if it could be an issue to do with the
device connecting as a USB 2.0 device to the host, but then being passed
as a USB 1.1 to the domU; and if that is the case, whether there is a
possible work-around.

Gordan