invalid address returned by usb_alloc_coherent on dockstar

[Martin Fuzzey]

>
> That's where it's going wrong.  Buffers allocated by dma_alloc_coherent()
> are already DMA coherent and must not be passed to dma_map_single().  I
> believe USB has some way to be told that the buffer is already suitable
> for DMA without needing additional handling.

Yes,
setting
urb->transfer_flags  = URB_NO_TRANSFER_DMA_MAP
will do this

Regards,

Martin