From: Philippe Gerum <rpm@xenomai.org>
To: Michael Smith <2michael.smith@gmail.com>, xenomai@xenomai.org
Subject: Re: [Xenomai] RTDM !xnpod_unblockable_p() question
Date: Wed, 13 Aug 2014 14:52:45 +0200 [thread overview]
Message-ID: <53EB5F9D.8000905@xenomai.org> (raw)
In-Reply-To: <CANWkrRN=ExZ4qgcXp8+d2NOzBHUvWb2u6Zu8twmr8Vo2VZnnqg@mail.gmail.com>
On 08/13/2014 02:28 PM, Michael Smith wrote:
> Hi
> I have been struggling with this problem for days on end, but there is just
> not enough information in the code
> or documentation for me to solve it.
> I am calling rtdm_mutex_lock() inside a device driver module. It is called
> by my PCI probe function as
> the driver is initializing.
> I keep on getting the error message:
> Xenomai: assertion failed at kernel/xenomai/skins/rtdm/drvlib.c:1534
> (!xnpod_unblockable_p())
> And the resultant -EPERM error message from the return of the function.
>
> I know these checks were inserted to stop any call from an incorrect
> context. But as far as the documentation states
> it can be called from a kernel module.
The doc (2.6) reads:
* This service can be called from:
*
* - Kernel-based task
* - User-space task (RT)
The generic "kernel module" context is not mentioned. You get -EPERM
because you cannot call this from a probe() routine, which runs in
secondary/pure linux mode. Acquiring a RTDM mutex requires the caller to
run in real-time mode.
> Also as the mail form March 2006 states
> http://www.xenomai.org/pipermail/xenomai/2006-March/003116.html
>
> !xnpod_unblockable_p():
> - allows blockable RT-context (kernel and user threads)
> - rejects user threads in secondary mode
> - rejects Linux threads
>
> Is there something I'm missing with regards to the calling context?
> Are there any other situations this could also produce this return?
> Because as far as I can see it should fine being called in a kernel module.
>
> Thanks
> Michael Smith
> _______________________________________________
> Xenomai mailing list
> Xenomai@xenomai.org
> http://www.xenomai.org/mailman/listinfo/xenomai
>
--
Philippe.
next prev parent reply other threads:[~2014-08-13 12:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-13 12:28 [Xenomai] RTDM !xnpod_unblockable_p() question Michael Smith
2014-08-13 12:52 ` Philippe Gerum [this message]
2014-08-13 12:55 ` Philippe Gerum
2014-08-13 20:04 ` Gilles Chanteperdrix
[not found] ` <CANWkrROgE=AVv_Qq9hkvS+kJ+Wx1zepOjJQ2gAX7qwNYJqhYBw@mail.gmail.com>
2014-08-14 7:02 ` [Xenomai] Fwd: " Michael Smith
2014-08-14 7:20 ` Philippe Gerum
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