From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752425AbZHUFCl (ORCPT ); Fri, 21 Aug 2009 01:02:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751897AbZHUFCk (ORCPT ); Fri, 21 Aug 2009 01:02:40 -0400 Received: from g1t0029.austin.hp.com ([15.216.28.36]:1982 "EHLO g1t0029.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751343AbZHUFCk (ORCPT ); Fri, 21 Aug 2009 01:02:40 -0400 Date: Thu, 20 Aug 2009 23:02:40 -0600 From: Alex Chiang To: Andi Kleen Cc: "H. Peter Anvin" , Suresh Siddha , "mingo@redhat.com" , "tglx@linutronix.de" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] x86: add /proc/cpuinfo/physical id quirks Message-ID: <20090821050240.GA4198@ldl.fc.hp.com> References: <20090814192730.GA6431@ldl.fc.hp.com> <1250279799.3077.41.camel@sbs-t61.sc.intel.com> <20090819210251.GD13061@ldl.fc.hp.com> <1250794594.2754.10.camel@sbs-t61.sc.intel.com> <20090820205425.GF13061@ldl.fc.hp.com> <20090820210342.GC29994@basil.fritz.box> <20090820212024.GG13061@ldl.fc.hp.com> <1250803577.2754.30.camel@sbs-t61.sc.intel.com> <4A8DC349.5060508@zytor.com> <20090821003232.GD29994@basil.fritz.box> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090821003232.GD29994@basil.fritz.box> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Andi Kleen : > > I agree... if this ID is used for topology detection, we > > shouldn't replace it arbitrarily with information from BIOS > > just to hope that it matches the motherboard stencil. > > *Furthermore*, there is no reason why motherboard stencilAs > > are purely numeric... consider the rather obvious case of two > > rows of four CPUs; they may have CPU slots labelled A1, A2, > > A3, A4, B1, B2, B3, B4. It might very well be the right > > thing to support arbitrary strings for platforms we > > recognize. > > Maintaining a manual mapping to strings in the kernel to such > strings would be just crazy. You would need a new entry for > basically every system. Well, ideally we could read it from a standard location, say evaluating the ACPI _SUN method for the cpu object and then plug that answer into a standard kernel data structure. Hardware vendors can stick whatever they want into that method; the kernel just passes it through to userspace. It's what we do for PCI slots today, and I wrote a patch for ia64 that does that type of fixup: fe086a7. > The reason to correct SOCKETID is that it it is output on errors. > If it is numerical and you know it's wrong you can correct it, > and then you can identify the right CPU. Otherwise you lose. I think numerical vs. ascii is the wrong way to think about it, since ACPI could provide either. /ac