Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758734AbYFWOij (ORCPT ); Mon, 23 Jun 2008 10:38:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756068AbYFWOic (ORCPT ); Mon, 23 Jun 2008 10:38:32 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:48575 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755459AbYFWOib (ORCPT ); Mon, 23 Jun 2008 10:38:31 -0400 Date: Mon, 23 Jun 2008 15:20:45 +0100 From: Alan Cox To: David Brownell Cc: lkml , Thomas Gleixner , Ingo Molnar , hpa@zytor.com Subject: Re: [patch] x86 supports NO_IRQ convention Message-ID: <20080623152045.07a21216@lxorguk.ukuu.org.uk> In-Reply-To: <200806230429.36298.david-b@pacbell.net> References: <200806221953.18849.david-b@pacbell.net> <20080623100823.61213c3f@lxorguk.ukuu.org.uk> <200806230429.36298.david-b@pacbell.net> X-Mailer: Claws Mail 3.4.0 (GTK+ 2.12.8; x86_64-redhat-linux-gnu) Organization: Red Hat UK Cyf., Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, Y Deyrnas Gyfunol. Cofrestrwyd yng Nghymru a Lloegr o'r rhif cofrestru 3798903 Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 769 Lines: 23 On Mon, 23 Jun 2008 04:29:36 -0700 David Brownell wrote: > On Monday 23 June 2008, Alan Cox wrote: > > Zero is not a valid IRQ in the kernel mapping of things. > > That's counter-factual: There are historical reasons for the timer tick (which isn't visible outside arch code) being 0 on x86. > I certainly agree it'd be convenient to be able to just test > for IRQ being nonzero. 0 means "no IRQ" in things like dev->irq. Lots of driver code assumes this and it has been decreed 'correct'. Alan -- 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/