Re: Missing COMEDI Functions

On Tue, 2005-03-01 at 09:57 -0500, Kenneth Jacker wrote:
> Jan: 
> 
> OK, I'm going to start out *real* slow ...
> 
>   jg> I have a simple script modprobe'ing all necessary modules and
>   jg> issuing a comedi_config.
>   jg>
>   jg> Something like this:
>   jg> modprobe rtai_hal
> 
> I tried this:
> 
>    # modprobe rtai_hal
>    FATAL: Module rtai_hal not found.
> 
> How can 'modprobe' be made aware that RTAI's modules are in /usr/realtime/modules?
> Isn't it, by default, just looking in "/lib/modules/`uname -r`"?

On my system, RTAI modules were installed in 
/lib/modules/`uname -r`/rtai/ by the rtai-modules package I built from
comedi-source.

> Are you sure it is OK to call comedi_open() from init_module()?
> 
> I have a feeling I'm confusing "real-time priority" and executing in
> "kernel space" (which I believe is 'init_module()'s situation).

Your feeling's right. Only your RT_TASK started by rt_task_make_periodic
and friends is executed by the RT scheduler. init_module is executed as
a "normal" kernel process. (In fact the kernel doesn't know yet that
this is a RT module.)

You might really want to have a look at the RTAI programming guide even
though it's a little bit outdated (no 2.6 kernel etc.).

Regards,
Jan

Received on 2005-03-01Z16:27:52