PROBLEM: USB isochronous urb leak on EHCI driver

[Alan Stern]

On Tue, 6 Jan 2015, Michael Tessier wrote:

> > > That is interresting, however, I have an older kernel running an OHCI 
> > > driver which is able to handle 4 codecs. Same usb hardware (codecs and 
> > > hub), but older kernel on a different CPU, with much less power. This 
> > > makes me believe that there's a solution to make it work...
> > 
> > Of course there is: Install an OHCI host controller and use it to drive your codecs.  It should work fine.
> > 
> > The periodic scheduling algorithm for OHCI is very different from the algorithm for EHCI.
> 
> According to your knowledge, how much time would you think it takes to
> change the EHCI driver with an OHCI one?

I don't understand the question.

>  And can you tell if the OHCI driver
> will work on my hardware given that the Host controller of the i.MX512 is
> a USB2.0 host controller? (OHCI was implemented for USB 1.x from what I
> understand)

The OHCI driver works with OHCI hardware and the EHCI driver works with 
EHCI hardware.  OHCI is USB-1.1 and EHCI is USB-2.  They are not 
interchangeable.

> I tried to do so several days ago with the built-in configurator
> (I am using "ltib"), but the configurator does not allow selecting the
> OHCI driver; I tried manually but it turned into compiler errors...

It looks like the configurator is smart; it won't let you select the 
wrong driver for your hardware.

Alan Stern