[LAU] USB, realtime, practical considerations

[nescivi]

Hiho,

On Wednesday 19 November 2008 20:16:24 Lee Revell wrote:
> > Whilst my 2.6.24.7-rt17 kernel and disabling all hardware and services
> > unneeded for audio seems to have gotten rid of those nasty xruns, I live
> > in fear that they will return.  My main worry is how I organise my USB
> > devices.
> >
> > My laptop (ThinkPad Z61m) has 3 USB ports.  I have several devices that
> > need to be connected to them, meaning that I need to use USB hubs.
> >
> > Here are some assumptions (or guesses) that I have made, on which I
> > would appreciate comment:
> >
> > * It would be best to balance the devices across the 3 ports.
> >
> > * My soundcard is a Behringer UCA202, capable of sampling at a maximum
> > of 48kHz @ 16bits x 2 channels.  I'm guessing that this will have the
> > greatest data rate of all attached devices.
> >  - Should it have its own port?
>
> Yes.  This will probably use more bandwidth than all the other devices
> combined.
>
> >  - Can USB 2.0 take more than this (like another device?)
>
> No USB 2.0 audio devices have Linux support AFAIK.

No USB 2.0 audio devices adhere to the usb-audio standard, and their 
manufacturers have not opened up their protocol.

sincerely,
Marije