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@ladisch.de
<mailto:clemens@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