Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757575AbYFWLaC (ORCPT ); Mon, 23 Jun 2008 07:30:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753097AbYFWL3n (ORCPT ); Mon, 23 Jun 2008 07:29:43 -0400 Received: from smtp122.sbc.mail.sp1.yahoo.com ([69.147.64.95]:26096 "HELO smtp122.sbc.mail.sp1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752341AbYFWL3m (ORCPT ); Mon, 23 Jun 2008 07:29:42 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=pacbell.net; h=Received:X-YMail-OSG:X-Yahoo-Newman-Property:From:To:Subject:Date:User-Agent:Cc:References:In-Reply-To:MIME-Version:Content-Disposition:Message-Id:Content-Type:Content-Transfer-Encoding; b=ssDIbEGlMFXOmC5xHDWscPv+mN9Quj/6op46NTCTmT5Visc2dOxrhSOGpWxQC3lwWROWCjKcA26qXV3+6Dimy011M5fQo8vk4etMQZHAPACejGlgWBepzEib0avQeIFhFzWi12IjU6kMAiGiZ9+PU8HiylJvOJGcXpOEVpgY5ww= ; X-YMail-OSG: oGRnkvUVM1ku5PAZzOhs_SbgkgD2DxLYpwfEtm6ica79fSq2DtbtmyviMrKPOKknh1Ko9pspunbNjiQYFx9txO.uvhTyRe4OgZ575BxkHyPErPdPYr7U3ZC5QeMGTPDTKKs- X-Yahoo-Newman-Property: ymail-3 From: David Brownell To: Alan Cox Subject: Re: [patch] x86 supports NO_IRQ convention Date: Mon, 23 Jun 2008 04:29:36 -0700 User-Agent: KMail/1.9.9 Cc: lkml , Thomas Gleixner , Ingo Molnar , hpa@zytor.com References: <200806221953.18849.david-b@pacbell.net> <20080623100823.61213c3f@lxorguk.ukuu.org.uk> In-Reply-To: <20080623100823.61213c3f@lxorguk.ukuu.org.uk> MIME-Version: 1.0 Content-Disposition: inline Message-Id: <200806230429.36298.david-b@pacbell.net> 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: 1048 Lines: 28 On Monday 23 June 2008, Alan Cox wrote: > Zero is not a valid IRQ in the kernel mapping of things. That's counter-factual: CPU0 CPU1 0: 42851354 6500253 IO-APIC-edge timer 1: 475459 45904 IO-APIC-edge i8042 8: 0 1 IO-APIC-edge rtc0 9: 135 18 IO-APIC-fasteoi acpi 12: 5232181 495206 IO-APIC-edge i8042 ... That's on x86. A quick survey of other boards around here shows many that use IRQ 0 too. I certainly agree it'd be convenient to be able to just test for IRQ being nonzero. Presumably only one driver would ever end up using IRQ 0 on x86, so other drivers could ignore the fact that testing for nonzero would mean "not the timer irq" rather than "no irq assigned". - Dave -- 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/