linuxaudio.org

On 05/25/2011 01:36 AM, Aurélien Leblond wrote:

quoted text
>>> * The USB Controller is the dreaded EHCI USB Controller: Intel*>>* Corporation 5 Series/3400 Series Chipset USB2 Enhanced Host Controller*>>* (rev 05)*>>* But the soundcard I'm usins is USB2, not USB 1.*>Hello Aurélien,

>> Afaik this doesn't matter, both USB2 and USB1 cards have issues when>used with full duplex on this USB controller or this Rate Matching hub>thing. But maybe this needs some digging in old mails/forum threads, I

>

>> could be wrong on this.

>

>

> Damn, as far as my research went, I only thought the problem was only

> when mixing USB1 and USB2 devices on these ports...

>

> I actually did some research... I knew these ports had issue with USB1

> but couldn't find anything about USB2...

>

http://lists.linuxaudio.org/pipermail/linux-audio-user/2010-June/070353....
So not mixing USB1 and USB2 devices but mixing a device performing

Full-Speed isochronous-out transactions with a device performing

asynchronous transactions. I've tested my Edirol UA-25 with this chipset

too and no matter what I tried, full duplex wouldn't work. Does your

machine have a Rate Matching Hub? If so could this be the device that

does asynchronous transactions maybe? Just guessing here. Or is USB2

isochronous and USB1 asynchronous?
Best,
Jeremy

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