From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754794Ab1LIUYs (ORCPT ); Fri, 9 Dec 2011 15:24:48 -0500 Received: from mga09.intel.com ([134.134.136.24]:18394 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754766Ab1LIUYq (ORCPT ); Fri, 9 Dec 2011 15:24:46 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.67,351,1309762800"; d="scan'208";a="85537859" Message-ID: <4EE26E8F.9010000@linux.intel.com> Date: Fri, 09 Dec 2011 12:24:47 -0800 From: Andi Kleen User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.15) Gecko/20110303 Thunderbird/3.1.9 MIME-Version: 1.0 To: Jean Delvare CC: Andi Kleen , linux-kernel@vger.kernel.org, kay.sievers@vrfy.org, trenn@suse.de, davej@redhat.com, axboe@kernel.dk, hpa@zytor.com, herbert@gondor.hengli.com.au, ying.huang@intel.com, lenb@kernel.org Subject: Re: [PATCH 01/10] Add driver auto probing for x86 features References: <1323304882-27953-1-git-send-email-andi@firstfloor.org> <1323304882-27953-2-git-send-email-andi@firstfloor.org> <20111208103540.4778b896@endymion.delvare> <20111208144516.GE24062@one.firstfloor.org> <20111209211601.08dabc88@endymion.delvare> In-Reply-To: <20111209211601.08dabc88@endymion.delvare> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Can you guarantee that there is no asymmetric system already working > today? I used to have an asymmetric system myself, but we generally subset the CPU feature flags to be the same everywhere and I didn't change any per CPU stepping checks as they were there. > If you can't, then your approach could cause a regression. This > is why I am asking for an API change to let drivers pass a specific CPU > to x86_match_cpu(). There are at least two drivers who would take > benefit of this. Your patch set is supposed to only add driver > auto-loading, and while cleaning up the code in the process is nice, I > think you should avoid driver behavior changes, these are out of scope > for such a patch set. I undoed that change to the coretemp driver and there's no other AFAIK. Generally most drivers only check the boot cpu. -Andi