[Xenomai] Xenomai-3 and native RTDM question

[Xenomai] Xenomai-3 and native RTDM question

[Anders Blomdell]

With Xenomai-3, will it be possible to use the native RTDM an a vanilla kernel, or
only on PREEMPT_RT kernels? The reason that I ask, is that I need to upgrade the
software in our labs (vanilla kernels, mostly) and would like to get comedi 
(www.comedi.org) to work with RTDM (so I get all the drivers from comedi,
the analogy double effort seems like a bad idea to me).

In the best of worlds, native RTDM could be pushed into the kernel staging area 
where comedi currently lives, and perhaps make the RTAI part of comedi easier
to support.

/Anders


-- 
Anders Blomdell                  Email: anders.blomdell@control.lth.se
Department of Automatic Control
Lund University                  Phone:    +46 46 222 4625
P.O. Box 118                     Fax:      +46 46 138118
SE-221 00 Lund, Sweden

Re: [Xenomai] Xenomai-3 and native RTDM question

[Philippe Gerum]

On 02/28/2014 01:03 PM, Anders Blomdell wrote:
> With Xenomai-3, will it be possible to use the native RTDM an a vanilla kernel, or
> only on PREEMPT_RT kernels?

Any kernel will do, provided it fits the user requirements in terms of 
response and execution time. PREEMPT_RT is not a pre-requisite for x3, 
it's an option, just like the Cobalt co-kernel is. There are projects 
currently based on x3 over plain 3.x kernels, only to leverage the 
legacy RTOS emulation capabilities.

  The reason that I ask, is that I need to upgrade the
> software in our labs (vanilla kernels, mostly) and would like to get comedi
> (www.comedi.org) to work with RTDM (so I get all the drivers from comedi,
> the analogy double effort seems like a bad idea to me).

In all fairness, Alex - the Analogy author - tried hard to contribute to 
Comedi at a time when the project was stalled, and also to avoid 
duplicate effort:
http://osdir.com/ml/comedi/2006-04/msg00017.html
https://lkml.org/lkml/2009/5/6/543

The intent was to port Comedi over RTDM since day one. Apparently, it 
turned out that Alex could not find anyone to work with from the Comedi 
team for evolving the code, hence Analogy.

-- 
Philippe.

Re: [Xenomai] Xenomai-3 and native RTDM question

[Anders Blomdell]

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On 2014-02-28 16:02, Philippe Gerum wrote:
> On 02/28/2014 01:03 PM, Anders Blomdell wrote:
>> With Xenomai-3, will it be possible to use the native RTDM an a
>> vanilla kernel, or only on PREEMPT_RT kernels?
> 
> Any kernel will do, provided it fits the user requirements in terms
> of response and execution time. PREEMPT_RT is not a pre-requisite for
> x3, it's an option, just like the Cobalt co-kernel is. There are
> projects currently based on x3 over plain 3.x kernels, only to
> leverage the legacy RTOS emulation capabilities.
> 
> The reason that I ask, is that I need to upgrade the
>> software in our labs (vanilla kernels, mostly) and would like to
>> get comedi (www.comedi.org) to work with RTDM (so I get all the
>> drivers from comedi, the analogy double effort seems like a bad
>> idea to me).
> 
> In all fairness, Alex - the Analogy author - tried hard to contribute
> to Comedi at a time when the project was stalled, and also to avoid
> duplicate effort: http://osdir.com/ml/comedi/2006-04/msg00017.html 
> https://lkml.org/lkml/2009/5/6/543
> 
> The intent was to port Comedi over RTDM since day one. Apparently, it
> turned out that Alex could not find anyone to work with from the
> Comedi team for evolving the code, hence Analogy.
Yes, that comedi got into the kernel staging area really made realtime stuff hard. If I 
understand it correctly, RTDM was also not possible for vanilla kernels at that time?

I think it might be worth a new try.

/Anders
- -- 
Anders Blomdell                  Email: anders.blomdell@control.lth.se
Department of Automatic Control
Lund University                  Phone:    +46 46 222 4625
P.O. Box 118                     Fax:      +46 46 138118
SE-221 00 Lund, Sweden

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