Hello, Correct me if I'm wrong, but there is no user space interface, similar to the dma_buf_start_cpu_access()/dma_buf_end_cpu_access() to handle IO coherency. That is, on the platforms, where the SW is responsible for IO coherency handling, the following sequences: - write to the buffer - DMA read or - DMA write - read from the buffer may be problematic. Thanks, Alexey _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel