Re: [LAU] USB on ThinkPad T520

From: Robin Gareus <robin@email-addr-hidden>
Date: Sun, 13 May 2012 20:15:49 +0200

> On 05/13/2012 07:45 PM, plutek wrote:
>> From: Robin Gareus <robin@email-addr-hidden>
>> Date: Sun, 13 May 2012 08:57:26 +0200
>>
>>> On 05/13/2012 03:13 AM, plutek wrote:
>>>> From: Karsten Wiese <fzuuzf@email-addr-hidden>
>>>> Date: Sat, 12 May 2012 23:18:22 +0200
>>>>
>>>>> 2012/5/12 Clemens Ladisch <clemens@email-addr-hidden>:
>>>>>> 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?
>
> No, not that I can tell. "0000:00:1d.0" is the USB hub/controller, right?

yes.

> The idea is to use the uhci_hcd (USB1) driver instead of ehci_hcd
> (USB2). -- Maybe the module is not loaded?
>
> `lsmod | grep uhci_hcd`

yeah... nothing.

> If they're modules: `rmmod ehci_hcd; modprobe uhci_hcd`; that'll force
> all USB ports into 1.X mode; may be worth a try before playing with
> dedicated per port bindings.

well, when i do that, this happens:

rmmod ehci_hcd
(lsmod shows neither ehci nor uhci)

modprobe uhci_hcd
(lsmod shows BOTH ehci and uhci)

rmmod uhci_hcd
(lsmod shows only ehci)
(USB devices don't appear in qjackctl)

i.e., it seems like USB devices show ONLY when ehci is loaded.

> Anyway, there might be something else going on: as both Karsten and
> Clemens noted, these "Intel Corporation Cougar Point [..] controllers
> use a different driver" and "There have been fixes recently. Try
> updating the kernel."

yeah, i'm starting to play with more recent kernels.... so far nothing does any better! :-(

cheers!
.pltk.
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Received on Mon May 14 00:15:02 2012