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=-8.8 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,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT 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 C0BDCC04A6B for ; Wed, 8 May 2019 15:22:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7EECD216F4 for ; Wed, 8 May 2019 15:22:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="i8s8Py93" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728005AbfEHPWr (ORCPT ); Wed, 8 May 2019 11:22:47 -0400 Received: from mail-pf1-f196.google.com ([209.85.210.196]:46290 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727800AbfEHPWp (ORCPT ); Wed, 8 May 2019 11:22:45 -0400 Received: by mail-pf1-f196.google.com with SMTP id y11so178246pfm.13; Wed, 08 May 2019 08:22:44 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=auSrnHuAF31y4BaeRC5x0jkMuUVcEeYH6Csq4j1xC8U=; b=i8s8Py93BMqyZZJqhZiyl63ogF3U5EV3QLlaXIsCZKVdFMUdw2wr+LAksQ2tepaM5j X3TugxIrq5VsD0S6yQjzxt9BVFi42TPi7FC5fprIdpRoqIYbKszLuhIeCxnCHJ2oZSQC 5L9fsYW8/fa+rH34BTITqiyEfxiQWiI3krl4qXcScUiq5BdWH0r8qZgJnvKzk64P/kqZ uSm7scuppFD3sHVsipA7ewBypFxgCqVjfPsQnF5j2XJcPrWBEUapqjv/Q/XBoDsHnYo2 N6jPDseEjZNRgwQf37WdbU+c9DeDiuJckIIpwsCG64ykPcsawnlioxzIUboZq86nxzH8 4nzA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=auSrnHuAF31y4BaeRC5x0jkMuUVcEeYH6Csq4j1xC8U=; b=VIz/9lgPeCZ4zpB+NPxWY+OSahC3xye4j9KgMXHveaPIOzxh76w0jp1s2498tQau2k p2HOcvVJATnvlf+qePRM5uW5YzJQVcT0XrbFc6BfFtvHlgQB+FV8bphJwGnpJa9cslqw vj9PBTj0CUzW6lSik3KuOLq5PJgjZ6uxOHQp2cUBxKcI7ObtbRR5MvYIHzyLgrZYJaUm UC76b5ek63OfoVSAtYzRAi9C/dA/5sj2+868qofw3utLJiBbfEyWX3wxZE5R9tTn3wsd iET2TDET/s8AnlBt87fz2WysIYgqYjP8M7mLuCtTQgpCPsJPlA89el4VxWzYbPz2g9rq bWNQ== X-Gm-Message-State: APjAAAUjxRZgE6zU+jOk02GMNQNHO3KEh1TxtZXxD2urKzDGdxFp1vw0 2vNRjCUcszKbJsnHo0LUzZ8= X-Google-Smtp-Source: APXvYqyh4Rcu8AKgqWB/bHOS8P/RcWdBaNrxTfj+rnQY/N2YMUnY7kbALFzc7TkaJ7h1QJ2cWLL1+w== X-Received: by 2002:a62:6b44:: with SMTP id g65mr49587206pfc.27.1557328964044; Wed, 08 May 2019 08:22:44 -0700 (PDT) Received: from localhost.localdomain ([104.238.181.70]) by smtp.gmail.com with ESMTPSA id o73sm7459360pfi.137.2019.05.08.08.22.38 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Wed, 08 May 2019 08:22:43 -0700 (PDT) From: Changbin Du To: corbet@lwn.net, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de Cc: x86@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Changbin Du , Mauro Carvalho Chehab Subject: [PATCH v4 07/27] Documentation: x86: convert earlyprintk.txt to reST Date: Wed, 8 May 2019 23:21:21 +0800 Message-Id: <20190508152141.8740-8-changbin.du@gmail.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190508152141.8740-1-changbin.du@gmail.com> References: <20190508152141.8740-1-changbin.du@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This converts the plain text documentation to reStructuredText format and add it to Sphinx TOC tree. No essential content change. Signed-off-by: Changbin Du Reviewed-by: Mauro Carvalho Chehab --- .../x86/{earlyprintk.txt => earlyprintk.rst} | 122 ++++++++++-------- Documentation/x86/index.rst | 1 + 2 files changed, 67 insertions(+), 56 deletions(-) rename Documentation/x86/{earlyprintk.txt => earlyprintk.rst} (51%) diff --git a/Documentation/x86/earlyprintk.txt b/Documentation/x86/earlyprintk.rst similarity index 51% rename from Documentation/x86/earlyprintk.txt rename to Documentation/x86/earlyprintk.rst index 46933e06c972..11307378acf0 100644 --- a/Documentation/x86/earlyprintk.txt +++ b/Documentation/x86/earlyprintk.rst @@ -1,52 +1,58 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============ +Early Printk +============ Mini-HOWTO for using the earlyprintk=dbgp boot option with a USB2 Debug port key and a debug cable, on x86 systems. You need two computers, the 'USB debug key' special gadget and -and two USB cables, connected like this: +and two USB cables, connected like this:: [host/target] <-------> [USB debug key] <-------> [client/console] -1. There are a number of specific hardware requirements: - - a.) Host/target system needs to have USB debug port capability. - - You can check this capability by looking at a 'Debug port' bit in - the lspci -vvv output: - - # lspci -vvv - ... - 00:1d.7 USB Controller: Intel Corporation 82801H (ICH8 Family) USB2 EHCI Controller #1 (rev 03) (prog-if 20 [EHCI]) - Subsystem: Lenovo ThinkPad T61 - Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx- - Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- SERR- TAbort- SERR- /grub.cfg.) + .. note:: + If you are using Grub, append it to the 'kernel' line in + /etc/grub.conf. If you are using Grub2 on a BIOS firmware system, + append it to the 'linux' line in /boot/grub2/grub.cfg. If you are + using Grub2 on an EFI firmware system, append it to the 'linux' + or 'linuxefi' line in /boot/grub2/grub.cfg or + /boot/efi/EFI//grub.cfg. On systems with more than one EHCI debug controller you must specify the correct EHCI debug controller number. The ordering @@ -96,14 +104,15 @@ and two USB cables, connected like this: controller. To use the second EHCI debug controller, you would use the command line: "earlyprintk=dbgp1" - NOTE: normally earlyprintk console gets turned off once the - regular console is alive - use "earlyprintk=dbgp,keep" to keep - this channel open beyond early bootup. This can be useful for - debugging crashes under Xorg, etc. + .. note:: + normally earlyprintk console gets turned off once the + regular console is alive - use "earlyprintk=dbgp,keep" to keep + this channel open beyond early bootup. This can be useful for + debugging crashes under Xorg, etc. - b.) On the client/console system: + b) On the client/console system: - You should enable the following kernel config option: + You should enable the following kernel config option:: CONFIG_USB_SERIAL_DEBUG=y @@ -115,27 +124,28 @@ and two USB cables, connected like this: it up to use /dev/ttyUSB0 - or use a raw 'cat /dev/ttyUSBx' to see the raw output. - c.) On Nvidia Southbridge based systems: the kernel will try to probe + c) On Nvidia Southbridge based systems: the kernel will try to probe and find out which port has a debug device connected. -3. Testing that it works fine: +Testing +======= - You can test the output by using earlyprintk=dbgp,keep and provoking - kernel messages on the host/target system. You can provoke a harmless - kernel message by for example doing: +You can test the output by using earlyprintk=dbgp,keep and provoking +kernel messages on the host/target system. You can provoke a harmless +kernel message by for example doing:: echo h > /proc/sysrq-trigger - On the host/target system you should see this help line in "dmesg" output: +On the host/target system you should see this help line in "dmesg" output:: SysRq : HELP : loglevel(0-9) reBoot Crashdump terminate-all-tasks(E) memory-full-oom-kill(F) kill-all-tasks(I) saK show-backtrace-all-active-cpus(L) show-memory-usage(M) nice-all-RT-tasks(N) powerOff show-registers(P) show-all-timers(Q) unRaw Sync show-task-states(T) Unmount show-blocked-tasks(W) dump-ftrace-buffer(Z) - On the client/console system do: +On the client/console system do:: cat /dev/ttyUSB0 - And you should see the help line above displayed shortly after you've - provoked it on the host system. +And you should see the help line above displayed shortly after you've +provoked it on the host system. If it does not work then please ask about it on the linux-kernel@vger.kernel.org mailing list or contact the x86 maintainers. diff --git a/Documentation/x86/index.rst b/Documentation/x86/index.rst index 0e3e73458738..d9ccc0f39279 100644 --- a/Documentation/x86/index.rst +++ b/Documentation/x86/index.rst @@ -13,3 +13,4 @@ x86-specific Documentation exception-tables kernel-stacks entry_64 + earlyprintk -- 2.20.1