Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934730AbYGCHL1 (ORCPT ); Thu, 3 Jul 2008 03:11:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753602AbYGCG6Q (ORCPT ); Thu, 3 Jul 2008 02:58:16 -0400 Received: from yw-out-2324.google.com ([74.125.46.28]:30805 "EHLO yw-out-2324.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754758AbYGCFLg (ORCPT ); Thu, 3 Jul 2008 01:11:36 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=LCKsVEBbHDzdKEkz1V2ksaJyOH1y2yyhE0rHzfdqH47sWpIvLUH36M01Dl5N+DKF3w iS+DLP/E2/p1Qg/m1bKm5cvp+829sXXtIOyfg1J7ehK+Y/9v8qG0xQD8lfuLXhIeJBFv rDx5SOpR6IxFtZkEjV0FCOcto/fo667D/RmdY= Message-ID: Date: Thu, 3 Jul 2008 14:11:22 +0900 From: "Magnus Damm" To: "Alan Cox" Subject: Re: [PATCH] uio: User IRQ Mode Cc: "=?ISO-8859-1?Q?Uwe_Kleine-K=F6nig?=" , "linux-kernel@vger.kernel.org" , "gregkh@suse.de" , "akpm@linux-foundation.org" , "hjk@linutronix.de" , "lethal@linux-sh.org" , "tglx@linutronix.de" In-Reply-To: <20080702123158.2c4fefc6@lxorguk.ukuu.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080702105951.22648.2197.sendpatchset@rx1.opensource.se> <20080702121153.4d464885@lxorguk.ukuu.org.uk> <20080702114224.GB6891@digi.com> <20080702123158.2c4fefc6@lxorguk.ukuu.org.uk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 882 Lines: 23 On Wed, Jul 2, 2008 at 8:31 PM, Alan Cox 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/