Re: [Xenomai-help] newbie question

[Philippe Gerum <rpm@xenomai.org>]

Ignacio García Pérez wrote:
> Hi,
> 
> I'm quite new to xenomai (switching from RTAI). I noticed that the
> latency_rt.ko module fails to start the timer if the posix skin module
> (xeno_posix.ko) is loaded. Is this the expected behaviour?
>

Yes and no. There is a change pending in my tree that makes rt_time_start() a 
bit smarter, trying its best effort to check whether the requested setting fits 
any current one, in which case the call returns without error. In the case you 
mentioned, both timer setups at nucleus level asked for oneshot, so this should 
have been ok with this patch, instead of bailing out on error rather uselessly. 
The UVM skin already enforces this for instance. I have just committed it to the 
SVN repo.

But on the long-term, I recall that Jan once asked for a normalized approach, 
allowing the timer to be set at configuration/loadup time for each skin, just 
keeping the system call as is for legacy/unusual/dynamic purposes. I agree with 
that, most of us don't really need to fiddle with the timer settings while the 
application runs, so having it statically configurable is more user-friendly and 
less error-prone.

-- 

Philippe.