Re: [RFC 3/3] stk1160: Use non-coherent buffers for USB transfers

[Christoph Hellwig]

> +     dma_sync_single_for_cpu(&urb->dev->dev, urb->transfer_dma,
> +             urb->transfer_buffer_length, DMA_FROM_DEVICE);

You can't ue dma_sync_single_for_cpu on non-coherent dma buffers,
which is one of the major issues with them.