Re: Comedi drivers and RTLinux

From: Calin A. Culianu <calin_at_ajvar.org> · Date: Thu, 12 Dec 2002 17:17:00 -0500 (EST)

On Thu, 12 Dec 2002, LEYRIE Jean-Michel wrote:

> Hello all,
>
> I have a newbie question :
> Are Comedie drivers suitable for RTLinux?
>
> If I use Comedi drivers, they are in user space so not real time.
> If I use KComedi drivers, they are in kernel space, but with RTLinux, the kernel is a low priority task.

Comedi is suitable for hard realtime with RTLinux.

Kcomedilib (if compiled with realtime support) is code that sits in
"kernel space" but is suitable for running under a realtime task.

Remember, even your own realtime code sits in kernel space but is
executed with (most) interrupts off as a realtime priority task.

Phrased another way.. the idea of your RT program's sitting inside kernel
memory space (as a kernel module) doesn't mean that it is running as
a linux task.

>
> Am I wrong?
>
> Regards,
> Jean-Michel.
>
>
>
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