PROBLEM: USB isochronous urb leak on EHCI driver

Michael Tessier michael.tessier at axiontech.ca
Tue Feb 10 10:21:45 AEDT 2015


> > > > > > 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.
> > 
> > What do you mean by that? The host controller is embedded in the i.MX CPU...
> > Changing the CPU is not really an option to me. Unless I am missing 
> > something?
>
> I didn't realize you were talking about an i.MX-based system.  On a computer with a free PCI slot, it's easy to add an OHCI controller.  
> iMX isn't as accomodating.
>
> If there's no way to add an extra USB controller to your system then the only choice is to upgrade the driver software.
>
> Alan Stern

Okay; I did my homeworks. We've loaded kernel V3.16 (Oct 14th, 2015) on an i.MX51 plattform and the problem is still there. Unless an important change occured in V3.19, it appears that the latest kernel is not the solution for us. So we're still not able to use 4 codecs on our i.MX plattform.

So just to make things clearer:
- We have customers waiting for a solution with that hardware (this hardware is already delivred AND used);
- We have important comittments and severe penalties ($$$) if we're not able to deliver on time (due for March 15th);
- We've already looked at a hardware solution, which corresponds to replace current units ($$$$$), so that is not really an option for us;

So as a last resort, I'm wondering, where is the USB expert who could help us solving our problem? Any suggestions?

If we are to get into debugging the USB driver, we would do it with the current kernel used (V2.6.31). What are the better tools to get into that? I guess a USB analyzer (hardware) would be the smart thing? Any brand name to suggest?

Any other ideas for a solution will be really appreciated.

Regards,
Michael Tessier.


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