This is a completely broken usage of the mmap interface. if you use mmap on a device file you must use the actual mmap for the data transfer. Our interface for zero copy reads/writes is O_DIRECT, and that requires not special memory allocation, just proper alignment. -- 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