> so you mean to use a chdev isnt a good idea! Why? Speed? For your requirement its best to let the drivers do the data collection and sharing!! Leave out the user-space application to just know the result (success/failure). > I have read some books and has made a chdev to communicate with > userspace, but now i dont know how fast this is. As mentioned i need > throughput... :( If you have to share data between the user and kernel space then you have copy_to_user and copy_from_user APIs.. If you need the through put do the communication at the driver level.. don't let the buffers come to user space and then pass it again to the next device.. ;) -Jinu -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/