From patchwork Wed Nov 21 09:31:42 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andy Shevchenko X-Patchwork-Id: 10692209 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B646214DE for ; Wed, 21 Nov 2018 09:31:47 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A29412B81C for ; Wed, 21 Nov 2018 09:31:47 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 93DE42B824; Wed, 21 Nov 2018 09:31:47 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4C7472B81C for ; Wed, 21 Nov 2018 09:31:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729456AbeKUUF3 (ORCPT ); Wed, 21 Nov 2018 15:05:29 -0500 Received: from mga18.intel.com ([134.134.136.126]:12006 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726620AbeKUUF3 (ORCPT ); Wed, 21 Nov 2018 15:05:29 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Nov 2018 01:31:45 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,260,1539673200"; d="scan'208";a="110332068" Received: from black.fi.intel.com ([10.237.72.28]) by orsmga002.jf.intel.com with ESMTP; 21 Nov 2018 01:31:43 -0800 Received: by black.fi.intel.com (Postfix, from userid 1003) id CB399107; Wed, 21 Nov 2018 11:31:42 +0200 (EET) From: Andy Shevchenko To: "Rafael J. Wysocki" , Len Brown , linux-acpi@vger.kernel.org, Prarit Bhargava Cc: Andy Shevchenko Subject: [PATCH v1] ACPI: SPCR: Consider baud rate 0 as preconfigured state Date: Wed, 21 Nov 2018 11:31:42 +0200 Message-Id: <20181121093142.2363-1-andriy.shevchenko@linux.intel.com> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Since SPCR 1.04 [1] the baud rate of 0 means a preconfigured state of UART. Assume firmware or bootloader configures console correctly. [1]: https://docs.microsoft.com/en-us/windows-hardware/drivers/serports/serial-port-console-redirection-table Signed-off-by: Andy Shevchenko --- drivers/acpi/spcr.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c index 9d52743080a4..ea92d88c02a6 100644 --- a/drivers/acpi/spcr.c +++ b/drivers/acpi/spcr.c @@ -148,6 +148,12 @@ int __init acpi_parse_spcr(bool enable_earlycon, bool enable_console) } switch (table->baud_rate) { + case 0: + /* + * SPCR 1.04 defines 0 as a preconfigured state of UART. + * Assume firmware or bootloader configures console correctly. + */ + break; case 3: baud_rate = 9600; break;