Intro and question about High speed Isochronous

Engineering ee at
Thu May 1 23:48:34 UTC 2008

> -----Original Message-----
> From: owner-freebsd-usb at
> >  I started using ugen and got most of the code ported. Then I
> > found out ehci does not support isochronous!
> How did you try to use this?

It fails with EIO when I open ugen0.1 - which is the isochronous endpoint.
If I go through a hub to force it to be USB 1.0, it works fine. Looking
throught the ehci source seems to confirm that it just doesn't handles
isochronous, and throws an error

> > 	Is there a new USB stack coming with high-speed iso? Will
> it work with
> > ugen? If not ugen, how do I get at it?
> My advice would be not to use libusb, just prepare your own kernel
> module. In most cases it is much simpler than ugen. Have a look at
> simple drivers like uscanner to see how to start with the USB
> kernel driver.

Thanks. I will take a look at uscanner, but if it uses ehci I will be in the
same boat.

> > 	Is anyone working on a UVC driver? I don't need all the
> features, just to
> > get at the stream data.
> You might want to have a look at Luigi Rizzo's work on video:

Yes, I've been looking at that with a lot of interest. Unfortunately, my
cameras are not supported, and I'm looking to use UVC cameras, as I believe
this will be the standard soon.


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