Re: [rtl] help for a newbie

[Loren Frank <loren@neurostat.mgh.harvard.edu>]

> 
> We use Matrox video cards which have a standard Linux driver. I modified
> the driver slightly so that whenever a frame is ready a task in the RT
> area is called. In this way I close a telescope acquisition servo at the
> nominal 30Hz frame rate. As Ron says, the user space driver can easily
> handle the full frame rate, it was just convenient to link it with
> Rt-Linux as I already had so much code for the telescope drive running
> under Rt.
> 
> 	Theo

That sounds very much like what I need to do. So ... it seems I have two
options:

1. modify the driver to ensure that only RT-Linux friendly calls are made in
the ISR (this seems very non trivial to me).

2. Set up an RT ISR that services the interrupt and then causes the normal
kernel space driver to be called.

For this second option, I can image one easy way to do it. I could set up
the RT process to handle the interrupt and then have the RT ISR raise a soft
interrupt of some other number which would then be serviced by the normal
driver ISR. That seems fairly easy to set up, but wasteful of interrups. 
Are there any other relatively simple approaches?


Thanks,


Loren