Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757932AbYHRWEk (ORCPT ); Mon, 18 Aug 2008 18:04:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754031AbYHRWEa (ORCPT ); Mon, 18 Aug 2008 18:04:30 -0400 Received: from accolon.hansenpartnership.com ([76.243.235.52]:55758 "EHLO accolon.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752968AbYHRWE3 (ORCPT ); Mon, 18 Aug 2008 18:04:29 -0400 Subject: Re: [PATCH] pci: change msi-x vector to 32bit From: James Bottomley To: "Eric W. Biederman" Cc: Yinghai Lu , Alan Cox , "H. Peter Anvin" , Jesse Barnes , Ingo Molnar , Thomas Gleixner , Andrew Morton , linux-kernel@vger.kernel.org, Andrew Vasquez In-Reply-To: References: <200808160326.m7G3QR1G012726@terminus.zytor.com> <86802c440808152342m772d5eabs59a9c93ffe4cf557@mail.gmail.com> <1218898238.3940.6.camel@localhost.localdomain> <20080816163945.74d487e9@lxorguk.ukuu.org.uk> <1218903209.3940.14.camel@localhost.localdomain> <86802c440808161156rf48f23ai9d77ce3cab36f02a@mail.gmail.com> <1218918341.3940.49.camel@localhost.localdomain> <86802c440808161334q75a7d019ofade0b6cabf3f74d@mail.gmail.com> <1218919547.3940.57.camel@localhost.localdomain> <86802c440808161517y1eaa5a4eo817b8a1bf75945be@mail.gmail.com> <1218928162.3940.62.camel@localhost.localdomain> <1219093158.3261.70.camel@localhost.localdomain> Content-Type: text/plain Date: Mon, 18 Aug 2008 17:04:21 -0500 Message-Id: <1219097061.3261.76.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 (2.22.3.1-1.fc9) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1598 Lines: 37 On Mon, 2008-08-18 at 14:45 -0700, Eric W. Biederman wrote: > > Yes, agree with the above except the static irq number ... although once > > that's hidden from the user, I suppose I really don't care any more. > > There is no point at all in having an irq number if it is not visible > to user space. > > Reaching a point where we don't export irq numbers to user space is > a hard problem. We have the irq balancer in user space (gag) and as > well as interfaces like /proc/interrupts, and for old ISA devices > there is no way to autodetect the configuration. So it requires a lot > of work. Sure, but you have 16 (or whatever) legacy interrupts. You still call them 1-16 (or ISA-1 through ISA-16). By the time we reach this stage, we're essentially doing string table lookups for the interrupts, so there's no need to pre-allocate them (except as a possible arch implementation detail). > The obvious first step is still to remove the architecture dependence > on irq number, and introduce another way of talking about irqs. Then > we can proceed to change the driver and the user space interfaces. > > I completely agree that irq number 99.9% of the time should be a completely > abstract token. Sure, although one nice reason for doing the abstraction first is that it stops people imposing fragile numbering schemes on irq ... James -- 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/