For what it's worth, I tried force ing USB 1.1 mode on the pi with my UA-25 and 
that resulted in a hard lock as well. Disappointing at this point since I've 
worked with audio on slower embedded machines before ...

On Jul 26, 2013, at 7:19 PM, John Canning <[email protected]> wrote:

> Thanks for getting back to me Dan
> 
> 
> On Fri, Jul 26, 2013 at 11:50 PM, Dan Wilcox <[email protected]> wrote:
> Actually I miss-typed. The issue is with "Isochronous" usb mode: 
> http://www.raspberrypi.org/phpBB3/viewtopic.php?f=28&t=29226 Looks like 
> things should be better for USB 2 audio devices, but still issues with USB 
> 1.1 devices (aka mine :P):
> 
>> While Isoc has improved for pretty much everyone using USB2.0 devices 
>> (USB1.1 will still suffer from lost packets due to split transaction 
>> breakage noted elsewhere) I'm still annoyed at my webcams "kinda working" - 
>> I get 1-2 seconds of uninterrupted video and then a half-garbled frame.
> 
> 
> On Jul 26, 2013, at 6:35 PM, Dan Wilcox <[email protected]> wrote:
> 
>> Sure, but that's only for certain types of USB devices. Some are working and 
>> others aren't. More "professional" sound cards require lower-latency/burst 
>> mode over USB which the PI firmware currently doesn't allow and/or doesn't 
>> set the correct priority for. The issue AFAICT is that essentially the usb 
>> host is software defined on the SOC and they haven't optimized it for usb 
>> audio, or something like that.
>> 
>> For instance, I can get stereo out in Pd working fine with my Edirol UA-25 . 
>> If I enable an audio input, I get instant dropouts. Yeah, I guess it 
>> "works", but not well enough for me.
>> 
>> On Jul 26, 2013, at 6:27 PM, John Canning <[email protected]> 
>> wrote:
>> 
>>> Hi Dan,
>>> 
>>> Thanks for getting back to me. I'm still very new to the Pi but have found 
>>> this post that seems to say that it can work. I'm confused. What do you 
>>> reckon?
>>> 
>>> 
>>> 
>>> On Fri, Jul 26, 2013 at 11:02 PM, Dan Wilcox <[email protected]> wrote:
>>> Simply put, the RPI firmware does not work with USB audio correctly yet. 
>>> See this thread: 
>>> http://lists.puredata.info/pipermail/pd-list/2013-07/103261.html
>>> 
>>> I keep looking for fixes, but the way USB is handled, the only way for it 
>>> to work without dropouts is to have *nothing* else plugged into the usb bus 
>>> and ethernet disabled ... sucks.
>>> 
>>> On Jul 26, 2013, at 5:41 PM, [email protected] wrote:
>>> 
>>>> From: John Canning <[email protected]>
>>>> Subject: [PD] Raspberry Pi Behringer UCA222 boot problems
>>>> Date: July 26, 2013 5:40:49 PM EDT
>>>> To: Pure Data <[email protected]>
>>>> 
>>>> 
>>>> Hi Folks,
>>>> 
>>>> I have been trying for quite a while to get my Raspberry Pi to work in 
>>>> full duplex with Pd. I have installed the OS on the PdPi site and updated 
>>>> it. I am using a Behringer UCA222 for audio. When I change the USB speed 
>>>> down to 1 (dwc_otg.speed=1) in /boot/cmdline.txt my Pi won't boot with the 
>>>> soundcard plugged in. If I unplug the soundcard the Pi will boot but as 
>>>> soon as I plug it in the Pi crashes. Has anyone got any suggestions about 
>>>> why this is happening? 
>>>> 
>>>> Thanks,
>>>> John
>>> 
>>> --------
>>> Dan Wilcox
>>> @danomatika
>>> danomatika.com
>>> robotcowboy.com
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>> 
>> --------
>> Dan Wilcox
>> @danomatika
>> danomatika.com
>> robotcowboy.com
>> 
>> 
>> 
>> 
>> 
> 
> --------
> Dan Wilcox
> @danomatika
> danomatika.com
> robotcowboy.com
> 
> 
> 
> 
> 
> 

--------
Dan Wilcox
@danomatika
danomatika.com
robotcowboy.com





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