From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754918AbZHTUmv (ORCPT ); Thu, 20 Aug 2009 16:42:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753863AbZHTUmu (ORCPT ); Thu, 20 Aug 2009 16:42:50 -0400 Received: from mail.windriver.com ([147.11.1.11]:51335 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932134AbZHTUmj (ORCPT ); Thu, 20 Aug 2009 16:42:39 -0400 From: Jason Wessel To: gregkh@suse.de Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Jason Wessel , Ingo Molnar , Andrew Morton , Yinghai Lu , "Eric W. Biederman" , Alan Stern , Sarah Sharp , Randy Dunlap Subject: [PATCH 10/11] ehci-dbgp,documentation: Documentation updates for ehci-dbgp Date: Thu, 20 Aug 2009 15:39:57 -0500 Message-Id: <1250800798-31559-11-git-send-email-jason.wessel@windriver.com> X-Mailer: git-send-email 1.6.3.1.9.g95405b In-Reply-To: <1250800798-31559-10-git-send-email-jason.wessel@windriver.com> References: <1250800798-31559-1-git-send-email-jason.wessel@windriver.com> <1250800798-31559-2-git-send-email-jason.wessel@windriver.com> <1250800798-31559-3-git-send-email-jason.wessel@windriver.com> <1250800798-31559-4-git-send-email-jason.wessel@windriver.com> <1250800798-31559-5-git-send-email-jason.wessel@windriver.com> <1250800798-31559-6-git-send-email-jason.wessel@windriver.com> <1250800798-31559-7-git-send-email-jason.wessel@windriver.com> <1250800798-31559-8-git-send-email-jason.wessel@windriver.com> <1250800798-31559-9-git-send-email-jason.wessel@windriver.com> <1250800798-31559-10-git-send-email-jason.wessel@windriver.com> X-OriginalArrivalTime: 20 Aug 2009 20:41:18.0368 (UTC) FILETIME=[91A49200:01CA21D6] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add missing information about requirements of using the EHCI usb debug controller as well as to mention you can use a debug controller other than the first one in the system. Signed-off-by: Jason Wessel Cc: Greg KH Cc: Ingo Molnar Cc: Andrew Morton Cc: Yinghai Lu Cc: "Eric W. Biederman" Cc: Alan Stern Cc: Sarah Sharp Cc: Randy Dunlap --- Documentation/kernel-parameters.txt | 2 +- Documentation/x86/earlyprintk.txt | 39 +++++++++++++++++++++++++++++++++- 2 files changed, 38 insertions(+), 3 deletions(-) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 7936b80..34332ec 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -670,7 +670,7 @@ and is between 256 and 4096 characters. It is defined in the file earlyprintk= [X86,SH,BLACKFIN] earlyprintk=vga earlyprintk=serial[,ttySn[,baudrate]] - earlyprintk=dbgp + earlyprintk=dbgp[debugController#] Append ",keep" to not disable it when the real console takes over. diff --git a/Documentation/x86/earlyprintk.txt b/Documentation/x86/earlyprintk.txt index 607b1a0..f19802c 100644 --- a/Documentation/x86/earlyprintk.txt +++ b/Documentation/x86/earlyprintk.txt @@ -7,7 +7,7 @@ and two USB cables, connected like this: [host/target] <-------> [USB debug key] <-------> [client/console] -1. There are three specific hardware requirements: +1. There are a number of specific hardware requirements: a.) Host/target system needs to have USB debug port capability. @@ -42,7 +42,35 @@ and two USB cables, connected like this: This is a small blue plastic connector with two USB connections, it draws power from its USB connections. - c.) Thirdly, you need a second client/console system with a regular USB port. + c.) You need a second client/console system with a high speed USB 2.0 + port. + + d.) The Netchip device must be plugged directly into the physical + debug port on the "host/target" system. You cannot use a USB hub in + between the physical debug port and the "host/target" system. + + The EHCI debug controller is bound to a specific physical USB + port and the Netchip device will only work as an early printk + device in this port. The EHCI host controllers are electrically + wired such that the EHCI debug controller is hooked up to the + first physical and there is no way to change this via software. + You can find the physical port through experimentation by trying + each physical port on the system and rebooting. Or you can try + and use lsusb or look at the kernel info messages emitted by the + usb stack when you plug a usb device into various ports on the + "host/target" system. + + Some hardware vendors do not expose the usb debug port with a + physical connector and if you find such a device send a complaint + to the hardware vendor, because there is no reason not to wire + this port into one of the physically accessible ports. + + e.) It is also important to note, that many versions of the Netchip + device require the "client/console" system to be plugged into the + right and side of the device (with the product logo facing up and + readable left to right). The reason being is that the 5 volt + power supply is taken from only one side of the device and it + must be the side that does not get rebooted. 2. Software requirements: @@ -56,6 +84,13 @@ and two USB cables, connected like this: (If you are using Grub, append it to the 'kernel' line in /etc/grub.conf) + On systems with more than one EHCI debug controller you must + specify the correct EHCI debug controller number. The ordering + comes from the PCI bus enumeration of the EHCI controllers. The + default with no number argument is "0" the first EHCI debug + 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 -- 1.6.3.1.9.g95405b