On Sat, 10 Aug 2013, Thomas Richter wrote:

> Which modules are relevant for handling the communication with the 
> device, and where would you suggest to start looking? I assume 
> yenta_socket is one thing for the cartbus adapter, then we have ehci_hcd 
> and ehci_pci. Do I assume correctly that we can rule out the ohci_hcd 
> module since that is not involved?

That's right.

>  What about other usb modules? I would 
> probably need a short recap on through which modules the user data flows 
> before the write is triggered, and which modules are involved in the 
> configuration of the NEC ehci host adapter.

Start with just the ones you have identified.  If that doesn't fix the 
problem then we can look further.

Alan Stern