[LAU] 3.8 vs. 3.5 for realtime USB performance

[Fernando Lopez-Lezcano]

On 06/28/2013 10:23 AM, Fernando Lopez-Lezcano wrote:
> On 06/27/2013 04:24 PM, James Stone wrote:
>>
>>
>> On Sun, Jun 9, 2013 at 10:04 AM, Clemens Ladisch <clemens at ladisch.de
>> <mailto:clemens at ladisch.de>> wrote:
>>
>>     James Stone wrote:
>>     > I am struggling to get usable realtime performance <512 latency
>> on my
>>     > Ubuntu Studio "low latency" kernels 3.8... The 3.5 kernel in
>> contrast works
>>     > fine. I put a bugreport in with Ubuntu, but it seems like no-one
>> else is
>>     > reporting the same problem. Makes me wonder if I am doing
>> something wrong.
>>     > Is there anything additional I should be trying, or is this a
>> known problem
>>     > that is being worked on by the kernel devs?
>>
>>     You have to wait for the next stable kernel:
>>     <http://git.kernel.org/linus/e194401783>
>>
>> Hi Clemens (and everyone else),
>>
>> This didn't fix the bug. See:
>>
>> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1191603
>>
>> and:
>>
>> https://bugs.launchpad.net/ubuntu/+source/linux-lowlatency/+bug/1185563
>>
>> Do you have any thoughts? Is this a problem with alsa/jack (as seems to
>> be being implied) or with the kernel?
>
> I'm building a kernel with the fix that's here:
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1136110
> It seems that it fixes the problem.

I can get 128x3 with no problems or glitches on an VSL181 USB2 
interface. Anything lower does not work but this is perfectly usable (in 
a short test).

-- Fernando