[LAU] USB on ThinkPad T520

[plutek]

From: Robin Gareus <robin at gareus.org>
Date: Sun, 13 May 2012 08:57:26 +0200

> On 05/13/2012 03:13 AM, plutek wrote:
>> From: Karsten Wiese <fzuuzf at googlemail.com>
>> Date: Sat, 12 May 2012 23:18:22 +0200
>> 
>>> 2012/5/12 Clemens Ladisch <clemens at ladisch.de>:
>>>> plutek wrote:
>>>>> i've been running AVLinux5.0.3 on a ThinkPad T61p for a while now....
>>>>> with an ART USB Dual Tube Pre, i can run Jack at 64 frames, 2 periods
>>>>>
>>>>> now i've got a new ThinkPad T520, and if i start jack on USB at 64*2
>>>>> i get hundreds of xruns in seconds.
>>>>
>>>> Both machines run (I assume) the same software?  Then the problem is
>>>> with the hardware, or its drivers.
>>>>
>>>> Please show the output of lspci and the contents of /proc/interrupts.
>>>>
>>>
>>> Thinkwiki says its got a QM67. That does USB 1.1 via the "Rate
>>> matching hub" and EHCI.
>>> I guess linux's hub driver is the culprit.
>> 
>> hmmmm.... shame.... lenovo specs said, of course, "USB 2.0".
>> mrph.
>> 
>> any way around this currently?
> 
> yes,
> 
> http://lists.linuxaudio.org/pipermail/linux-audio-dev/2010-October/029511.html

after i do:

# cd /sys/bus/pci/drivers/ehci_hcd/
# echo -n 0000:00:1d.0 > unbind

...the USB audio device no longer shows up in qjackctl.

did i misunderstand?

thanks... cheers!
.pltk.