Received: by 10.213.65.68 with SMTP id h4csp1458517imn; Mon, 26 Mar 2018 07:56:49 -0700 (PDT) X-Google-Smtp-Source: AIpwx49axx5gZI4KgbXrvAeRX0UlX3s6sb1eJ175n7detDoSSYLHW3/pnCN0r+l0C4ajJ56ouECp X-Received: by 10.101.98.82 with SMTP id q18mr4807676pgv.182.1522076209358; Mon, 26 Mar 2018 07:56:49 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1522076209; cv=none; d=google.com; s=arc-20160816; b=lBzZno8h4LmRnce9w5m/cmvaIK99mqtvUZKNgKZRC9udckEy8/XI9W1JCC0YGMvnGD In9AjniZIT6ZR0YWxXzQCgTg5x4N3NlT9IygJXtq/GPqLL4O+dxZJii/a+Vl4MnOmt8A XJ/FUFYFUOjbbTMIMNqlbHXx/nr384vOHPTn4/zBCN1LKj+G1hBhqehVLD6Tcesj9olx yavEieDMGLBUX7jcONlIjl1f3AA457ys+WRfKHD2TlGnBYRcHwy6MrAglmjbtUYp0/LN P8SSl8XicZ1b/JI4BuebSFTxOv5CrhXV0T63w7X7N7vPpSwdp4O2Lap4yrqDyQKUGcOF XEtw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :organization:references:in-reply-to:date:cc:to:from:subject :message-id:arc-authentication-results; bh=Xu5/88bQ34/enCEjrWmutFO2PovBPjbS8lNRQq+VLSY=; b=rdDprxv8t+N/e3Q9ftKcaq0J7dKdSbC8SLVA9G/LPMN2nPFh2ofbeAphN5z+cOnin3 cyub0ZTpoNNkMOY9ipFHqgW7+7NyTIritoknXs8bF+7kUie+oY5trSgefyQK0h8EOGTK aftggfiemK4nxvtgS1LTIIhTyZwVSAu2Px749GuISMNESutIzHUqcnpGws4KHtm9TZUV 8eQIM54B+y54pW+m/Pf1uBY1bEAObWgsx95mIskR47hdRakJYk0PNTbAJHQwoZR21G0o 6dn1TfpubgGFpjlknTJtrieeNNUD7ZFOxEPVvh/i9rjfT7MiRosd4pai77iDVxr0NGph Q3Qg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id h8si10240579pgr.370.2018.03.26.07.56.34; Mon, 26 Mar 2018 07:56:49 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752453AbeCZOz2 (ORCPT + 99 others); Mon, 26 Mar 2018 10:55:28 -0400 Received: from mga06.intel.com ([134.134.136.31]:29316 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752309AbeCZOzY (ORCPT ); Mon, 26 Mar 2018 10:55:24 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 26 Mar 2018 07:55:24 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,365,1517904000"; d="scan'208";a="211393188" Received: from acox1-desk1.ger.corp.intel.com ([10.252.139.204]) by orsmga005.jf.intel.com with ESMTP; 26 Mar 2018 07:55:21 -0700 Message-ID: <1522076116.16723.13.camel@linux.intel.com> Subject: Re: [PATCH v3] x86: i8237: Register based on FADT legacy boot flag From: Alan Cox To: hpa@zytor.com, Thomas Gleixner , Rajneesh Bhardwaj Cc: Anshuman Gupta , glx@linutronix.de, x86@kernel.org, mingo@redhat.com, rjw@rjwysocki.net, andriy.shevchenko@linux.intel.com, linux-kernel@vger.kernel.org Date: Mon, 26 Mar 2018 15:55:16 +0100 In-Reply-To: <8A68406D-B05E-4953-89D1-D2AB49904644@zytor.com> References: <1521714118-31282-1-git-send-email-anshuman.gupta@intel.com> <20180326054833.GA25173@raj-desk2.iind.intel.com> <8A68406D-B05E-4953-89D1-D2AB49904644@zytor.com> Organization: Intel Corporation Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.24.6 (3.24.6-1.fc26) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Can we probe safely for this device? 99% of the time yes the inb gives us a straight answer. However (and we've hit this with port 0x81 for real) there are concerns that some systems will trap those addresses into SMM and do weirdness that makes the 0xFF check fail. Alan