[LAU] reducing xruns (System configuration)

[Max]

On 20.07.2018 11:24, David Kastrup wrote:
> Ralf Mardorf <ralf.mardorf at alice-dsl.net> writes:
> 
>> On Thu, 2018-07-19 at 22:44 +0200, David Kastrup wrote:
>>> You are babbling. [snip]
>>>
>>> A lot of people get setups like that to work without rtirq .
>>
>> Hi,
>>
>> the OP on Wed, 2018-07-18 at 21:28 +0200 wrote "64 buffer size at 48kHz
>> 2 Periods/Buffer" and the OP on Thu, 2018-07-19 at 14:32 +0200 wrote
>> "Bus 003 Device 002: ID 08bb:29c2 Texas Instruments PCM2902C Audio CODEC".
>>
>> I'm not aware that a lot of people got this to work at all.
> 
> I missed the PCM2902C bit.  That chip is described in
> http://www.ti.com/product/PCM2902C/technicaldocuments and is USB full
> speed (namely USB1.1 speeds).  It is described as
> 
>      – USB Adaptive Mode for Playback
>      – USB Asynchronous Mode for Record
> 
> It sports something like 16bit/48kHz with 89dB SNR.  That is both with
> regard to attainable sound quality as well as USB bus behavior
> completely lacklustre.  I'd expect this kind of interface to be mostly
> soldered to mainboards directly where one would not expect to be able to
> change buses at all.
> 
> Or be part of some USB sound interface in the $10 price class.
> 
> So the idea to take this into low-latency realms with a view on realtime
> effects seems a bit optimistic indeed.  Actually out of place.  Maybe
> this isn't actually the interface we are dealing with but just something
> hardwired to the motherboard and thus cropping up in the lsusb output?

It's actually a behringer mixer (now legacy model afaik)... all right I 
will try a different card.

I bought the docking station which has 6 more USB ports (4 USB 3.0 and 2 
USB 2.0)

however:

  lsusb
Bus 002 Device 002: ID 8087:8000 Intel Corp.
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 8087:8008 Intel Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 004: ID 17ef:304f Lenovo
Bus 004 Device 003: ID 2109:0812 VIA Labs, Inc. VL812 Hub
Bus 004 Device 002: ID 2109:0812 VIA Labs, Inc. VL812 Hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 003: ID 8087:07dc Intel Corp.
Bus 003 Device 011: ID 046a:b090 Cherry GmbH
Bus 003 Device 030: ID 1686:0045 ZOOM Corporation H4 Digital Recorder
Bus 003 Device 028: ID 0fce:01e1 Sony Ericsson Mobile Communications AB
Bus 003 Device 010: ID 0424:2640 Standard Microsystems Corp. USB 2.0 Hub
Bus 003 Device 009: ID 0424:2514 Standard Microsystems Corp. USB 2.0 Hub
Bus 003 Device 006: ID 1a40:0101 Terminus Technology Inc. Hub
Bus 003 Device 008: ID 17ef:304e Lenovo
Bus 003 Device 007: ID 08bb:29c2 Texas Instruments PCM2902C Audio CODEC
Bus 003 Device 004: ID 2109:2812 VIA Labs, Inc. VL812 Hub
Bus 003 Device 002: ID 2109:2812 VIA Labs, Inc. VL812 Hub
Bus 003 Device 005: ID 0bda:5719 Realtek Semiconductor Corp.
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

no matter where I plug in the devices I can't seem to find how to use 
the Bus 4 USB 3.0. Could it be that it is only on the motherboard but 
not actually available to the user?

m.