From: "Magnus Damm" <magnus.damm@gmail.com>
To: "Alan Cox" <alan@lxorguk.ukuu.org.uk>
Cc: "Uwe Kleine-König" <Uwe.Kleine-Koenig@digi.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"gregkh@suse.de" <gregkh@suse.de>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"hjk@linutronix.de" <hjk@linutronix.de>,
"lethal@linux-sh.org" <lethal@linux-sh.org>,
"tglx@linutronix.de" <tglx@linutronix.de>
Subject: Re: [PATCH] uio: User IRQ Mode
Date: Thu, 3 Jul 2008 14:11:22 +0900 [thread overview]
Message-ID: <aec7e5c30807022211q3e06dbd9m143015cbf10cd81d@mail.gmail.com> (raw)
In-Reply-To: <20080702123158.2c4fefc6@lxorguk.ukuu.org.uk>
On Wed, Jul 2, 2008 at 8:31 PM, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
>> Note that the irq is disabled instead of acked. So this should not be a
>> problem. The userspace part then is responsible to ack (first) and
>> unmask the irq.
>
> That still doesn't make sense.
>
> If you call disable_irq in the IRQ handler you will deadlock because it
> waits until the IRQ handler has completed.
Right, the uio_userirq_handler() function should use
disable_irq_nosync() instead of disable_irq(). Otherwise we'll end up
waiting forever for IRQ_INPROGRESS to be cleared in synchronize_irq()
in the case of CONFIG_SMP.
Thanks!
/ magnus
next prev parent reply other threads:[~2008-07-03 7:11 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-02 10:59 Magnus Damm
2008-07-02 11:11 ` Alan Cox
2008-07-02 11:42 ` Uwe Kleine-König
2008-07-02 11:31 ` Alan Cox
2008-07-03 5:11 ` Magnus Damm [this message]
2008-07-03 10:23 ` Magnus Damm
2008-07-02 12:54 ` Hans J. Koch
2008-07-03 7:10 ` Uwe Kleine-König
2008-07-03 12:45 ` Hans J. Koch
2008-07-03 13:23 ` Paul Mundt
2008-07-03 19:55 ` Hans J. Koch
2008-07-04 2:55 ` Magnus Damm
2008-07-04 12:44 ` Hans J. Koch
2008-07-04 4:03 ` Magnus Damm
2008-07-04 6:01 ` Uwe Kleine-König
2008-07-04 7:48 ` Magnus Damm
2008-07-04 8:11 ` Uwe Kleine-König
2008-07-04 8:29 ` Paul Mundt
2008-07-04 13:39 ` Hans J. Koch
2008-07-04 8:16 ` Alan Cox
2008-07-04 13:32 ` Hans J. Koch
2008-07-04 13:26 ` Hans J. Koch
2008-07-04 22:51 ` Magnus Damm
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