Is there a better way (FIFOs)

[James Buckle]

>From: "Paolo Mantegazza" <mante at aero.polimi.it>
>
>As I said if one has just the need to set up a real time interrupt handler 
>then (s)he needs just rtai_hal.ko to be installed. It is possible to go 
>even further as shown in showroom: kernel/i386/rawirq and 
>kernel/i386/irqlat. In such a situation if it is further needed to 
>communicate back/forth the handler and user space rtai_fifos are enough. 
>That means you need to install just rtai_hal and rtai_fifos and nothing 
>else; no RTAI scheduler, no synch or any other interprocess communication 
>API.
>
>However rtai_fifos can use their kernel APIs in user space also through an 
>LXRT extension. Such an extension is enabled by default so if you insmod 
>fifos without disabling it you need the RTAI scheduler also. To disable 
>such an extension there is the need to follow what I suggested you above 
>(right now in both magma and vulcano CVSes there is a module param to do 
>that).
>
>I hope it is clearer now.
>
>If you decide to use the whole of RTAI for your application instead, then 
>avoid using fifos and use: maiboxes, msgq, intertask processes, mq, scbs 
>(at your choice). In showroom there is an example for almost any of them.
>
>Paolo.
>


Thanks for clearing all of that up - i think i follow now :)

I had a crack at using the FIFO signalling but couldnt get the GUI to accept 
signals despite knowing that the FIFO is being fed data (i can read bytes 
from it). I know someone else had the same problem (their post dated Mon, 11 
Nov 2002 10:21:44 +1100 in the archives) but I havent been able to contact 
them yet to see if they resolved it.  I'll keep trying but any hints are 
very welcome!

James