From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
To: JK.Behnke@web.de
Cc: xenomai@xenomai.org
Subject: Re: [Xenomai] rtdm driver open_rt/nrt handler question
Date: Thu, 26 Nov 2015 10:10:52 +0100 [thread overview]
Message-ID: <20151126091052.GC19641@hermes.click-hack.org> (raw)
In-Reply-To: <trinity-1b427f3b-dabe-48c1-a434-82562a3226e1-1448528416329@3capp-webde-bs12>
On Thu, Nov 26, 2015 at 10:00:16AM +0100, JK.Behnke@web.de wrote:
> Xenomai 2.6.3 documentation states, that the usage of open_rt handlers
> is deprecated
> as this feature will be removed in the future.
Xenomai 2.6.3 is very old now. It is not even the latest release in
the 2.6 branch. open_rt has been removed from Xenomai 3.
> As a consequence one cannot use rtdm_mutex_lock inside an nrt_open
> handler
> to synchronize multiple callers, as this will result in a
> (!xnpod_unblockable_p()) assertion.
> So using a spinlock would be the only solution in that situation.
> Is that true?
No, the caller is a Linux task, or a Xenomai task running in
secondary mode. As such, any Linux service can be used, such as
mutex or semaphores (the Linux ones).
>
> By the way, if an rtdm driver only supports RTDM_EXCLUSIVE mode, is
> there
> a need to synchronize concurrent calls to rt_dev_open on this device at
> all?
> I guess not, because the second caller will be refused.
> Is that also true?
Yes.
--
Gilles.
https://click-hack.org
next prev parent reply other threads:[~2015-11-26 9:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-26 9:00 [Xenomai] rtdm driver open_rt/nrt handler question JK.Behnke
2015-11-26 9:10 ` Gilles Chanteperdrix [this message]
2015-11-26 9:39 ` JK.Behnke
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