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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 7A2E7C47253 for ; Fri, 1 May 2020 15:07:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 55EDF20857 for ; Fri, 1 May 2020 15:07:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="guUWyREb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728993AbgEAPHY (ORCPT ); Fri, 1 May 2020 11:07:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37870 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728981AbgEAPHX (ORCPT ); Fri, 1 May 2020 11:07:23 -0400 Received: from mail-lj1-x242.google.com (mail-lj1-x242.google.com [IPv6:2a00:1450:4864:20::242]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9BE11C061A0C; Fri, 1 May 2020 08:07:21 -0700 (PDT) Received: by mail-lj1-x242.google.com with SMTP id f11so2900376ljp.1; Fri, 01 May 2020 08:07:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=upOUdSA1Qa3kRXGYSaZZPrHtnJP9z+HJ8x8GQ4kRPF8=; b=guUWyREbg1v99mp5JVpch/N8xFP0yadNEcjMtY4Pxt/EXZ0urMvwoGSVC9EvNyIyOW YYFdd+dKaAAjCGrr+awTct9/wUlUWLp+RkgMsok1KKhFb5jyFUXLfJj6AIXE1qorG7RE c+sdRcadiPRsq8NqlzxNMAec03sEEPXhYQHSe1ElCszSakwXTszYYsLTPpJLZ3Lh9wsz qGAwDDllm6eUquPi+JtmZZcrvXRQl1XwDC2kR2cusSIUolWZX2R+wNdMrYjRemti1Cx9 iB7zuvjbkarND9uY35ZaNnnS/ETdSYb5aevq/TNwMwyKAOpzwCXHS+btJhjwtv4AaaWP QptQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=upOUdSA1Qa3kRXGYSaZZPrHtnJP9z+HJ8x8GQ4kRPF8=; b=W4n5aWZ7yOcY3kZ182AOL+P+8ubnetL/kYr4wYeUQeUBoxmpi79DdSsHCc+hnYDXUZ UWFtL612KnjZDoNkQPr6uLiDMyMajbDObu7o1nb399kdkbCuplbTyYmQIMx/Xvwv+JE6 N/O0wtW7ik49BcNqxIMVy87XjLqYyYiX1iDQ/R1TbQ0HYRqtVvogo5B/MDCut2kVMpiA VCehYZ/oMijxPiMoQL6t4Nve51zw64kIAVqtQ93vTjEarSQumQ7+FypUJ3gemDW2u4Dz 18oBufoJR/wsRuEMXrYGgVyYHCnMgsy5eCxFtpbF4xjEhobTpdd+/QeseisJLR5pW5AE 2TvQ== X-Gm-Message-State: AGi0PuYwayT7pUTBOHiF/Ipl0wgOh2MIb+lMt/mXi6MFC2pWQ4SALQ72 WEmyxA/dgVjzJG+WcbSrwNI= X-Google-Smtp-Source: APiQypKlGD+iUIY9mDeLIe59axBBk5YzG667ZkaJqGWQfXMpFrhBLjtlipoZCkeeAPnYUSiTg5zyEA== X-Received: by 2002:a2e:91d4:: with SMTP id u20mr2699038ljg.248.1588345640064; Fri, 01 May 2020 08:07:20 -0700 (PDT) Received: from [192.168.0.74] ([178.233.178.9]) by smtp.gmail.com with ESMTPSA id o18sm2393090lfb.13.2020.05.01.08.07.14 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 01 May 2020 08:07:18 -0700 (PDT) Subject: Re: [RFC PATCH v2 0/3] Prefer working VT console over SPCR and device-tree chosen stdout-path To: Andy Shevchenko Cc: Sergey Senozhatsky , Greg Kroah-Hartman , Jiri Slaby , Petr Mladek , "open list:SERIAL DRIVERS" , Steven Rostedt , linux-arm Mailing List , Linux Kernel Mailing List , Andrew Morton , Andy Shevchenko , Arvind Sankar , Benjamin Herrenschmidt , Daniel Vetter , "David S. Miller" , Eric Biggers , Feng Tang , Grzegorz Halat , Lukas Wunner , Nicolas Pitre , Sam Ravnborg References: <20200430161438.17640-1-alpernebiyasak@gmail.com> <20200501013044.GA288759@jagdpanzerIV.localdomain> <818ba356-ba35-68de-b7bf-f145a89280f1@gmail.com> From: Alper Nebi Yasak Message-ID: <3cd630dd-9bb9-e975-7466-c3125aa6afa3@gmail.com> Date: Fri, 1 May 2020 18:07:10 +0300 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-serial-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org On 01/05/2020 16:16, Andy Shevchenko wrote: > On Fri, May 1, 2020 at 2:11 PM Alper Nebi Yasak > wrote: >> I'm assuming "by default" here means "without console arguments" >> regardless of firmware requests. This paragraph (with small changes) is >> repeated on many other Kconfig descriptions (drivers/tty/serial/Kconfig, >> drivers/tty/serial/8250/Kconfig, arch/sparc/Kconfig from grepping for >> '/dev/tty0' on **/Kconfig). >> >> From Documentation/admin-guide/serial-console.rst: >> >>> You can specify multiple console= options on the kernel command line. >>> [...] >>> Note that you can only define one console per device type (serial, video). >>> >>> If no console device is specified, the first device found capable of >>> acting as a system console will be used. At this time, the system >>> first looks for a VGA card and then for a serial port. So if you don't >>> have a VGA card in your system the first serial port will automatically >>> become the console. >> >> and later on: >> >>> Note that if you boot without a ``console=`` option (or with >>> ``console=/dev/tty0``), ``/dev/console`` is the same as ``/dev/tty0``. >>> In that case everything will still work. > > I'm wondering if behaviour is changed if you put console=tty1 instead > of console=tty0. Just tested again with the QEMU aarch64 VM. Comparing console=tty1 and console=tty0 cases: /proc/consoles has tty1 instead of tty0 (both also has ttyAMA0), and `echo '/dev/console is here' >>/dev/console` goes to vt1 instead of the currently visible vt. Same difference before and after this patchset.