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From: Jan Kiszka <jan.kiszka@domain.hid>
To: Philippe Gerum <rpm@xenomai.org>
Cc: Alexis Berlemont <berlemont.hauw@domain.hid>, xenomai@xenomai.org
Subject: Re: [Xenomai-help] Analogy cmd_write example explanation
Date: Thu, 01 Apr 2010 23:39:37 +0200	[thread overview]
Message-ID: <4BB51299.7070500@domain.hid> (raw)
In-Reply-To: <1270157042.2418.406.camel@domain.hid>

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Philippe Gerum wrote:
> __xn_exec_current is actually carrying a MASSIVE bug potential:
> - stick __xn_current to your favourite syscall, and implement two
> versions of that syscall, depending on the current calling mode for the
> shadow thread.
> - let people think that they should control the current mode of that
> thread using rt_task_set_mode() and this freaking horror monster called
> T_PRIMARY, before calling the syscall in question, to get either
> implementation A or B.
> - run the stuff, and surprise, get a linux signal between
> rt_task_set_mode and the syscall. Your thread is now NRT. Too bad, you
> wanted the RT side to run. You are toast.

That's a non-issue if the driver gets informed about the capability of
the caller to execute a service also in RT. In that case, if an RT
variant of the invoked service exist, the driver can simply issue the
well-know ENOSYS, despite the fact that it could handle the call right
now in NRT as well.

Jan


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  reply	other threads:[~2010-04-01 21:39 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-10 15:26 [Xenomai-help] Analogy cmd_write example explanation Daniele Nicolodi
2010-03-12 23:40 ` Alexis Berlemont
2010-03-13  9:28   ` Philippe Gerum
2010-03-13 16:13     ` Alexis Berlemont
2010-03-13 16:33       ` Philippe Gerum
2010-03-13 23:34         ` Alexis Berlemont
2010-03-14 16:34           ` Philippe Gerum
2010-03-15  7:50             ` Jan Kiszka
2010-03-15 23:30               ` Alexis Berlemont
2010-03-16  8:59                 ` Jan Kiszka
2010-03-18 20:35                 ` Philippe Gerum
2010-03-18 21:14                   ` Alexis Berlemont
2010-03-18 21:39                     ` Philippe Gerum
2010-04-01 19:47             ` Gilles Chanteperdrix
2010-04-01 21:13               ` Jan Kiszka
2010-04-01 21:22                 ` Philippe Gerum
2010-04-01 21:26                   ` Jan Kiszka
2010-04-01 21:31                     ` Philippe Gerum
2010-04-01 21:36                       ` Jan Kiszka
2010-04-01 21:48                         ` Philippe Gerum
2010-04-01 21:54                           ` Jan Kiszka
2010-04-01 22:00                             ` Philippe Gerum
2010-04-01 22:07                               ` Jan Kiszka
2010-04-01 22:53                                 ` Gilles Chanteperdrix
2010-04-01 22:58                                   ` Jan Kiszka
2010-04-01 23:08                                     ` Gilles Chanteperdrix
2010-04-02  0:04                                       ` Jan Kiszka
2010-04-02 10:39                                         ` [Xenomai-core] " Gilles Chanteperdrix
2010-04-02 11:11                                           ` Jan Kiszka
2010-04-02 11:14                                             ` Gilles Chanteperdrix
2010-04-02 11:28                                               ` Jan Kiszka
2010-04-13 20:41                                                 ` Philippe Gerum
2010-04-13 23:05                                                   ` Jan Kiszka
2010-04-14  7:22                                                     ` Philippe Gerum
2010-04-14  7:37                                                       ` Jan Kiszka
2010-04-14  7:51                                                         ` Jan Kiszka
2010-04-14  9:04                                                         ` Philippe Gerum
2010-04-14 17:13                                                           ` Gilles Chanteperdrix
2010-04-14 19:35                                                           ` Jan Kiszka
2010-04-14  8:24                                                   ` Gilles Chanteperdrix
2010-04-01 21:24               ` Philippe Gerum
2010-04-01 21:39                 ` Jan Kiszka [this message]
2010-04-01 21:59                   ` Philippe Gerum
2010-04-01 22:12                     ` Jan Kiszka
2010-04-01 21:50               ` Jan Kiszka
2010-04-01 21:54                 ` Gilles Chanteperdrix

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