From: Jan Kiszka <jan.kiszka@siemens.com>
To: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
Cc: "Mauerer, Wolfgang" <wolfgang.mauerer@siemens.com>,
Xenomai <xenomai@xenomai.org>
Subject: Re: [Xenomai] [PATCH] Revert "ipipe: ipipe_request_irq(), ipipe_free_irq() are root-only services"
Date: Thu, 20 Sep 2012 15:15:23 +0200 [thread overview]
Message-ID: <505B16EB.3040800@siemens.com> (raw)
In-Reply-To: <505B13B0.9020302@xenomai.org>
On 2012-09-20 15:01, Gilles Chanteperdrix wrote:
> On 09/20/2012 01:15 PM, Jan Kiszka wrote:
>
>> On 2012-09-20 12:57, Jan Kiszka wrote:
>>> On 2012-09-20 12:56, Jan Kiszka wrote:
>>>> On 2012-09-20 12:49, Philippe Gerum wrote:
>>>>> On 09/20/2012 12:37 PM, Jan Kiszka wrote:
>>>>>> This reverts commit 073ff1e8045d0311b8cf390687c0ba3619681672.
>>>>>>
>>>>>> Both service are NOT just root-only services. E.g., rtdm_irq_request
>>>>>> requires by specification support also over non-Linux contexts.
>>>>>
>>>>> Nack. We can't run the enable code for MSIs over non-root, and
>>>>> that code typically follows the irq request. Besides, we want to mask
>>>>> the source upon irq free to handle the SMP case properly, which we could
>>>>> not do from non-root with MSIs.
>>>>>
>>>>> So either we have both request+enable and free usable over non-root, or
>>>>> there is no point.
>>>>
>>>> OK, I get the point with legacy MSI. Then we have two other bugs to solve:
>>>> - in I-pipe as it holds a hardened spin lock across enable/disable (of
>>>> MSIs)
>>
>> I think this bug may only manifest over ARM as that arch does
>> enable/disable_irq() inside __ipipe_enable/disable_irqdesc - unless
>> something prevents that enabling will ever happen for interrupts that
>> need Linux locks to work. Is that assured?
>
>
> ARM does that because otherwise interrupts are not enabled after a call
> to eg. rtdm_irq_request, and calling rtdm_irq_enable does not work,
> calling request_irq is required to get them working.
The generic pattern Xenomai currently uses is xnintr_attach +
xnintr_enable. The latter happens to be rtdm_irq_enable as well. So,
doesn't xnintr_enable work at all? Or is it only not suited as interrupt
startup? Then, is that a new issue or something core-3.x specific?
Finally, can't we address it in xnarch_enable_irq?
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux
next prev parent reply other threads:[~2012-09-20 13:15 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-20 10:37 [Xenomai] [PATCH] Revert "ipipe: ipipe_request_irq(), ipipe_free_irq() are root-only services" Jan Kiszka
2012-09-20 10:49 ` Philippe Gerum
2012-09-20 10:56 ` Jan Kiszka
2012-09-20 10:57 ` Jan Kiszka
2012-09-20 11:06 ` Philippe Gerum
2012-09-20 11:15 ` Jan Kiszka
2012-09-20 11:27 ` Jan Kiszka
2012-09-20 13:01 ` Gilles Chanteperdrix
2012-09-20 13:15 ` Jan Kiszka [this message]
2012-09-20 14:12 ` Gilles Chanteperdrix
2012-09-20 15:00 ` Jan Kiszka
2012-09-20 15:13 ` Gilles Chanteperdrix
2012-09-20 13:10 ` Philippe Gerum
2012-09-20 13:54 ` Jan Kiszka
2012-09-20 14:05 ` Philippe Gerum
2012-09-20 15:07 ` Jan Kiszka
2012-09-20 15:16 ` Philippe Gerum
2012-09-20 15:45 ` Jan Kiszka
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