[LAU] Sound Devices USBPre2, UAC2 status

[alexander]

On 04/01/13 21:31, shal at free.fr wrote:
> Hi,
>
> Some old posts exist about the UAC2 support for the Sound Devices USBPre2 but some problem remains.
> The current status is that this sound card is supported as a USB 1.1 card in high-speed mode.
> But this card is not seen as a Usb Audio Class 2 on  Linux. On Mac OS X this card is recognized as UAC2.
>
>
> My principal problem is that the "device descriptor" provided by the card is always a USB1.1 class
> There is two modes of boot for the card (pressing the "1" button, the card is in full speed mode, without pressing in UAC2 mode)
> There is only one difference between these two modes in the lsusb -v : the "bInterval" go to 4 from 1.
>
> This is already view by Clemens on:
> http://lists.linuxaudio.org/pipermail/linux-audio-user/2011-October/081275.html
>
> In this another post, we can seen:
>
> Bernardo Barros wrote:
>> Ok, I reconnected without pressing "1".
>>
>> Bus 002 Device 002: ID 0926:0202
>> Device Descriptor:
>>    bNumConfigurations      2
> Strange, I have never 2 on bNumConfigurations !   Somebody can test it on its card ?
> This is perhaps my problem, my card only provides one "Configuration Descriptor".
> The second one is certainly the UAC2 "Configuration Descriptor".
>
>
> The lsusb without 1 pressed : http://pastebin.com/8yjjASv7
> The lsusb with 1 pressed : http://pastebin.com/pGFdjR4K
> The usbmon trace of the insertion of the usbpre2 (without "1")  : http://pastebin.com/pySC4Age
>
> This sound card is great, it is very disappointing to not be able to used it with all functionnalities.
>
> I search help in order to debug this problem.
> I am devlopper, I can test kernel patches without problem.
>
> Thank for any idea (or patch).
>
> Olivier
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>
Oliver check your SD thread 
http://forum.sounddevices.com/showthread.php?3785-Linux-status-for-usbPre2&highlight=linux 
Paul Isaacs of Sound Devices has posted a potentially helpful reply!