Re: USB Audio Passthrough

David Sutton
Sun, 02 Jun 2013 14:05:35 -0000

Hi Gordan,

On Sun, Jun 2, 2013 at 5:10 AM, Gordan Bobic <gordan@bobich.net> wrote:

> 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<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
>

I ''cheated'' in that I just passed one of the USB controllers
through to my
windows domU, then use a pair of USB headphones that I switch from one port
to another, depending on which VM i''m currently using. Not had any
issues
with it that way.

Regards,

  David


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