Re: [Xenomai-help] help: pipe + event flag group (or other synchronisation mechanism

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

Filip Van Rillaer wrote:
> Hello, 
> 
> Our application is written with some kind of super-loop scheduling : we
> have many drivers that call rt_event_signal (when data have been written
> to the hardware or new data are available to be processed) and 1 task
> that is calling rt_event_wait. After receiving an event, the superloop
> task is then reading/writing the data from/to the appropriate driver.
> Those calls to the drivers must never block (except to some locking to
> protect the consistency of data-structures) to garantuee the real-time
> behaviour of the application.
> Now we want to communicate with the Linux-domain and thought we have to
> use the Xenomai pipe-object for that purpose.
> 
> How can the superloop task in Xenomai receive an event from the
> pipe-object when data are available to be read/written (so without
> already reading the data)?
> 
> The ideal solution would be if one can ask the pipe-driver to call a
> user-callback function when there is a change in the status (read/write)
> or an equivalent system to the EPOLL interface (from the uclinux
> domain).

Xenomai posix skin has support for the "select" call, which requires
some support from each driver, and you can already select from a posix
message queue. This is another solution.

-- 


					    Gilles.