Maulik Mankad wrote: > The USB stack maps the buffer for DMA if the controller supports DMA. > MUSB controller can perform DMA as well as PIO transfers. > The buffer needs to be unmapped before CPU can perform > PIO data transfers. > > Export unmap_urb_for_dma() so that drivers can perform > the DMA unmapping in a sane way. Don't you also need to remap it when the transfer is complete to prevent usb core from unmapping something that's not mapped? David -- David Vrabel, Senior Software Engineer, Drivers CSR, Churchill House, Cambridge Business Park, Tel: +44 (0)1223 692562 Cowley Road, Cambridge, CB4 0WZ http://www.csr.com/ Member of the CSR plc group of companies. CSR plc registered in England and Wales, registered number 4187346, registered office Churchill House, Cambridge Business Park, Cowley Road, Cambridge, CB4 0WZ, United Kingdom -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
