From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8D67AC43143 for ; Mon, 1 Oct 2018 14:12:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 40A2E208D9 for ; Mon, 1 Oct 2018 14:12:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 40A2E208D9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729421AbeJAUuq (ORCPT ); Mon, 1 Oct 2018 16:50:46 -0400 Received: from mga12.intel.com ([192.55.52.136]:22296 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729386AbeJAUup (ORCPT ); Mon, 1 Oct 2018 16:50:45 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 01 Oct 2018 07:12:45 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,327,1534834800"; d="scan'208";a="91115618" Received: from shbuild888.sh.intel.com (HELO localhost) ([10.239.146.239]) by fmsmga002.fm.intel.com with ESMTP; 01 Oct 2018 07:12:42 -0700 Date: Mon, 1 Oct 2018 22:18:10 +0800 From: Feng Tang To: Borislav Petkov Cc: Thomas Gleixner , Ingo Molnar , H Peter Anvin , Peter Zijlstra , "Stuart R . Anderson" , alan@linux.intel.com, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] x86/earlyprintk: Add a force option for pciserial device Message-ID: <20181001141810.fbo3amfqnr5243mc@shbuild888> References: <20180928094008.23138-1-feng.tang@intel.com> <20180929163458.GA25608@zn.tnic> <20180930131619.jecqh4umrkmifavb@shbuild888> <20181001123916.GC7269@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181001123916.GC7269@zn.tnic> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Boris, On Mon, Oct 01, 2018 at 02:39:16PM +0200, Borislav Petkov wrote: > On Sun, Sep 30, 2018 at 09:16:19PM +0800, Feng Tang wrote: > > Got your point. As the following [,baudrate] is also optional, and this > > "force" could be the last option for pciserial. The check may be > > > > if (!strncmp(s, "force,", 6) || !strncmp(s, "force ", 6)) { > > force = 1; > > s += 6; > > } > > You have !strncmp(s, "force,", 6) twice in there. I have no clue what > you're trying to say. I was trying to address your last comments: "No, you need to force the presence of "," otherwise cmdlines like this: earlyprintk=pciserial,0:XX.X,forcedoodoo work too." As I rechecked, the baud rate for pciserial is optional, so there may be no ",baudrate" following the "force". So this 2 strncmp is to cover conditions for with and without baudrate. > > > Do you mean this? > > > > if (((classcode >> 16 != PCI_CLASS_COMMUNICATION_MODEM) && > > (classcode >> 16 != PCI_CLASS_COMMUNICATION_SERIAL)) || > > (((classcode >> 8) & 0xff) != 0x02)) /* 16550 I/F at BAR0 */ { > > if (!force) > > return; > > } > > Yes. Ok, thanks Thanks, Feng