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=-5.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 14309C43141 for ; Fri, 15 Nov 2019 04:34:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D98FC20728 for ; Fri, 15 Nov 2019 04:34:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="plD1YOaN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727113AbfKOEeA (ORCPT ); Thu, 14 Nov 2019 23:34:00 -0500 Received: from mail-pg1-f195.google.com ([209.85.215.195]:39637 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726755AbfKOEd7 (ORCPT ); Thu, 14 Nov 2019 23:33:59 -0500 Received: by mail-pg1-f195.google.com with SMTP id 29so5188056pgm.6; Thu, 14 Nov 2019 20:33:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=uG8EYto2G5KUs/xrRVV9nqvd+H7D1BzazmBvDXAUch4=; b=plD1YOaNtJ71eOne2Z0YRcvw2L0eBFV+IsZdz01pd3dF/+Cp7NEW+SaLgddIzKXvIb kv2oQTPWaU9yuuvo9mhmpZlgPLnVwIx8sBAiz4A9FDvwlESV8kTbUli5Crq9aI9MOXCf HlaVk45La7pdje3K/dt9Opmq3P6teL6SnnSkLRgp/XTIYRSFR8vsW8ODOj8mfKR67wEi aegHhKAy6bAszf8Vu1eZbUUhXXi2v7ltLq3ixDO9dqlx890OGZSwfLpFXG1d9CWLFZ59 I+9pZZSCHI7Zu947gxt/ktg3F+hdamMooXOsoFzv96ozqUF5hPZmBt+g39YCyaghndFu rtNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=uG8EYto2G5KUs/xrRVV9nqvd+H7D1BzazmBvDXAUch4=; b=J1d01wNZs5YzqpAmdbFPqwW76Hg2UvD2nv0rn8A+fM78m7sfQuv1RI8kZ3hzuT9/8k GRR8fznDTBkwGz057QMPwnjN1EALBtltN68XeLB73tCpJGHC+cdi8NWpT62r+KXpWu2a eYzdiRgUcH+nmNQGj5gzf/vQLo3FlV6TAsWHiNrcV5+OGEr1lfCmzYleiZey4cqApq2Z M1FqTs/irNalYLyLBrhl1Ecgp1TgdztZ0FI+1L/RxkERoIUnIoZK6fuxeBZakWoCekrT kG6wY8nF6pUrKp7aOYM7/hludotlfNIeEQ8pXkj/jvv4lUotTUVzH5lMXMg+SvXf4MR6 Vcpw== X-Gm-Message-State: APjAAAWGQ3LEzioigAfJOaYga0jUl1fUoMWGpAjdUYMzDX2dVJYjdm1p CX0PAHFSMq9Y8BUfOnbObPUyIXVhqGA= X-Google-Smtp-Source: APXvYqzdYiwsPqZoNlVml6tlzRZzQKB4JQJ2ZAJztAW0vdJWLBdWIj5wPzwiGCeMgkTS6VEnWQ+S3A== X-Received: by 2002:a62:aa0a:: with SMTP id e10mr5708723pff.46.1573792439044; Thu, 14 Nov 2019 20:33:59 -0800 (PST) Received: from localhost ([2401:fa00:8f:203:250d:e71d:5a0a:9afe]) by smtp.gmail.com with ESMTPSA id m11sm1769772pgd.62.2019.11.14.20.33.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 14 Nov 2019 20:33:57 -0800 (PST) Date: Fri, 15 Nov 2019 13:33:56 +0900 From: Sergey Senozhatsky To: Petr Mladek Cc: Jonathan Richardson , gregkh@linuxfoundation.org, jslaby@suse.com, sergey.senozhatsky@gmail.com, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Scott Branden , Ray Jui , Srinath Mannam Subject: Re: console output duplicated when registering additional consoles Message-ID: <20191115043356.GA220831@google.com> References: <20191114095737.wl5nvxu3w6p5thfc@pathway.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191114095737.wl5nvxu3w6p5thfc@pathway.suse.cz> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Gosh, that part of printk is really complex. On (19/11/14 10:57), Petr Mladek wrote: > For a proper solution we would need to match boot and real > consoles that write messages into the physical device. > But I am afraid that there is no support for this. Wouldn't those have same tty driver? --- kernel/printk/printk.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index f1b08015d3fa..a84cb20acf42 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2690,6 +2690,19 @@ static int __init keep_bootcon_setup(char *str) early_param("keep_bootcon", keep_bootcon_setup); +static bool known_console_driver(struct console *newcon) +{ + struct console *con; + + for_each_console(con) { + if (!(con->flags & CON_ENABLED)) + continue; + if (con->device && con->device == newcon->device) + return true; + } + return false; +} + /* * The console driver calls this routine during kernel initialization * to register the console printing procedure with printk() and to @@ -2828,6 +2841,9 @@ void register_console(struct console *newcon) if (newcon->flags & CON_EXTENDED) nr_ext_console_drivers++; + if (known_console_driver(newcon)) + newcon->flags &= ~CON_PRINTBUFFER; + if (newcon->flags & CON_PRINTBUFFER) { /* * console_unlock(); will print out the buffered messages