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Date: Tue, 10 Jul 2012 11:10:47 +0200
From: Philippe Gerum <rpm@xenomai.org>
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Subject: Re: [Xenomai] XDDP and inter-driver API.
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To: Sunetra Sashi <snmgmt19@gmail.com>
Cc: xenomai@xenomai.org

On 07/10/2012 11:03 AM, Sunetra Sashi wrote:
>
>
> On Tue, Jul 10, 2012 at 4:40 AM, Philippe Gerum <rpm@xenomai.org
> <mailto:rpm@xenomai.org>> wrote:
>
>     On 07/10/2012 04:30 AM, Sunetra Sashi wrote:
>
>         Hi,
>
>         I am trying to use the XDDP module in order to achieve
>         linux-xenomai domain
>         cross communication. However, when I install my module which
>         creates a
>         socket and binds its to the XDDP port, via the
>         *rtdm_socket(AF_RTIPC,
>         SOCK_DGRAM, IPCPROTO_XDDP)* call, it fails. Also, when I try to
>         open the
>         device on the linux side, via an *rtdm_open("/dev/rtp0",
>         O_RDWR)*, it also
>         fails.
>
>
>     Please report issues with all details, typically error codes and
>     return values. "call fails" is not enough.
>
>
> rtdm_socket call fails with error code 97. The rtdm_open fails with
> error code 19.
>
>
>     Although using rtdm_open() for /dev/rtp0 may work, this

Actually, no it won't. What would work is opening a RTDM device via the 
wrapped open() call routed to the Xenomai system, which is the converse way.

>     pseudo-device file should be opened using a plain open(2) call,
>     since we want to open the regular linux-side endpoint for the
>     communication.
>
>
> I am making these calls from within the kernel, not from user space.
> Hence I ended up using rtdm calls instead


/dev/rtp0 is a non-real-time user-space endpoint for the communication, 
between a regular linux application and a real-time component. It does 
not make sense to open it from kernel space.

>
>
>
>         Do I need to install any specific xenomai modules for this to work?
>
>
>     Obviously, yes. Check IPC drivers in the "Drivers" sub-menu of the
>     Xenomai configuration. You need to have
>     CONFIG_XENO_DRIVERS_RTIPC_XDDP enabled.
>
>
> I already checked this in the configuration, It is enabled. Should this
> also be set to y? CONFIG_XENO_DRIVERS_RTIPC. In my configuration it is
> set to m.

Did you load the xeno_rtipc module then?

> Should I see any modules loaded in /proc/xenomai/rtdm/protocol_devices?

Yes.

>
>
>
>         Thanks
>         Shweta
>         _________________________________________________
>         Xenomai mailing list
>         Xenomai@xenomai.org <mailto:Xenomai@xenomai.org>
>         http://www.xenomai.org/__mailman/listinfo/xenomai
>         <http://www.xenomai.org/mailman/listinfo/xenomai>
>
>
>
>     --
>     Philippe.
>
>
>


-- 
Philippe.