From owner-svn-doc-head@FreeBSD.ORG Thu May 8 19:40:48 2014 Return-Path: Delivered-To: svn-doc-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id C0092E85; Thu, 8 May 2014 19:40:48 +0000 (UTC) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id A0B4EB07; Thu, 8 May 2014 19:40:48 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.8/8.14.8) with ESMTP id s48JemfF042704; Thu, 8 May 2014 19:40:48 GMT (envelope-from dru@svn.freebsd.org) Received: (from dru@localhost) by svn.freebsd.org (8.14.8/8.14.8/Submit) id s48Jem7K042703; Thu, 8 May 2014 19:40:48 GMT (envelope-from dru@svn.freebsd.org) Message-Id: <201405081940.s48Jem7K042703@svn.freebsd.org> From: Dru Lavigne Date: Thu, 8 May 2014 19:40:48 +0000 (UTC) To: doc-committers@freebsd.org, svn-doc-all@freebsd.org, svn-doc-head@freebsd.org Subject: svn commit: r44794 - head/en_US.ISO8859-1/books/handbook/serialcomms X-SVN-Group: doc-head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-doc-head@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: SVN commit messages for the doc tree for head List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 08 May 2014 19:40:48 -0000 Author: dru Date: Thu May 8 19:40:48 2014 New Revision: 44794 URL: http://svnweb.freebsd.org/changeset/doc/44794 Log: Finish editorial review of Serial Console section. Some reshuffling to avoid redundancy. Should undergo a tech review to make sure all the details are correct and updated for the supported versions of FreeBSD. Sponsored by: iXsystems Modified: head/en_US.ISO8859-1/books/handbook/serialcomms/chapter.xml Modified: head/en_US.ISO8859-1/books/handbook/serialcomms/chapter.xml ============================================================================== --- head/en_US.ISO8859-1/books/handbook/serialcomms/chapter.xml Thu May 8 16:09:18 2014 (r44793) +++ head/en_US.ISO8859-1/books/handbook/serialcomms/chapter.xml Thu May 8 19:40:48 2014 (r44794) @@ -1879,6 +1879,19 @@ raisechar=^^ keyboard and leaving the mouse plugged in can fool the keyboard probe into thinking the keyboard is still there. + + + While most systems will boot without a keyboard, quite a + few will not boot without a graphics adapter. Some systems + can be configured to boot with no graphics adapter + by changing the graphics adapter + setting in the BIOS configuration to Not + installed. Other systems do not support this option and will + refuse to boot if there is no display hardware in the system. + With these machines, leave some kind of graphics card plugged + in, even if it is just a junky mono board. A monitor does not + need to be attached. + @@ -2082,164 +2095,108 @@ boot: During the third stage of the boot process, one can still switch between the internal console and the serial console by setting appropriate environment variables in the boot loader. - See for more + See &man.loader.8; for more information. - - - Tips for the Serial Console + + This line in /boot/loader.conf or + /boot/loader.conf.local + configures the boot loader and the kernel to send their boot messages to the serial + console, regardless of the options in /boot.config: + + console="comconsole" - + That line should be the first line of + /boot/loader.conf so that boot + messages are displayed on the serial console as early as possible. + + If that line does not exist, or if it is set to + console="vidconsole", the boot loader and + the kernel will use whichever console is + indicated by in the boot block. See + &man.loader.conf.5; for more information. + + At the moment, the boot loader has no option + equivalent to in the boot block, and + there is no provision to automatically select the internal + console and the serial console based on the presence of + the keyboard. + + + + While it is not required, it is possible to provide a + login prompt over the serial line. To + configure this, edit the entry for the serial port in + /etc/ttys using the instructions in + . If the speed of the serial port has been + changed, change std.9600 to match the + new setting. + + + + Setting a Faster Serial Port Speed By default, the serial port settings are 9600 baud, 8 bits, no parity, and 1 stop bit. To change the default - console speed, the following options are available: + console speed, use one of the following options: - Recompile the boot blocks with - BOOT_COMCONSOLE_SPEED set to the new - console speed. + Edit /etc/make.conf and set + BOOT_COMCONSOLE_SPEED to the new + console speed. Then, recompile and install the boot + blocks and the boot loader: + + &prompt.root; cd /sys/boot +&prompt.root; make clean +&prompt.root; make +&prompt.root; make install If the serial console is configured in some other way than by booting with , or if the serial console used by the kernel is different from the - one used by the boot blocks, add the following option + one used by the boot blocks, add the following option, with the desired speed, to a custom kernel configuration file and compile a new kernel: - options CONSPEED=19200 + options CONSPEED=19200 - Add the boot option to - /boot.config. See &man.boot.8; for - a description of how to add options to - /boot.config and a list of the - supported options. + Add the boot option to + /boot.config, replacing + 19200 with the speed to use. - Enable comconsole_speed in - /boot/loader.conf. This option - depends on console, - boot_serial, and - boot_multicons being set in - /boot/loader.conf too. An example - of using comconsole_speed to change - the serial console speed is: + Add the following options to + /boot/loader.conf. Replace + 115200 with the speed to + use. boot_multicons="YES" boot_serial="YES" -comconsole_speed="115200" +comconsole_speed="115200" console="comconsole,vidconsole" - + - + Entering the DDB Debugger from the Serial Line - To drop into the kernel debugger from the serial - console, compile a custom kernel with the following options. + To configure the ability to drop into the kernel debugger from the serial + console, add the following options to a custom kernel + configuration file and compile the kernel using the + instructions in . Note that while this is useful for remote diagnostics, it is also dangerous if a spurious BREAK is generated on the - serial port. + serial port. Refer to &man.ddb.4; and &man.ddb.8; for more + information about the kernel debugger. options BREAK_TO_DEBUGGER options DDB - - - - Getting a Login Prompt on the Serial Console - - While this is not required, it is possible to get a - login prompt over the serial line. - First, make sure that the boot messages are displayed and it - is possible to enter the kernel debugging session through - the serial console. - - Open /etc/ttys with a text editor - and locate the lines: - - ttyu0 "/usr/libexec/getty std.9600" unknown off secure -ttyu1 "/usr/libexec/getty std.9600" unknown off secure -ttyu2 "/usr/libexec/getty std.9600" unknown off secure -ttyu3 "/usr/libexec/getty std.9600" unknown off secure - - ttyu0 through - ttyu3 correspond to - COM1 through - COM4. Change - off to on for the - desired port. If the speed of the serial port has been - changed, change std.9600 to match the - new setting. - - The terminal type can also be changed from - unknown to the actual type of the serial - terminal. - - After editing the file, type kill -HUP - 1 to make this change take effect. - - - - - Changing Console from the Boot Loader - - This line in /boot/loader.conf - configures the boot loader and the kernel to use the serial - console: - - console="comconsole" - - This will take effect regardless of the settings in the - boot block discussed in the previous section. This line should be the first line of - /boot/loader.conf so as to see boot - messages on the serial console as early as possible. - - Likewise, to specify the internal console: - - console="vidconsole" - - If the boot loader environment variable - console is not set, the boot loader, and - subsequently the kernel, will use whichever console is - indicated by in the boot block. - - The console can be specified in - /boot/loader.conf.local or in - /boot/loader.conf. - - See &man.loader.conf.5; for more information. - - - At the moment, the boot loader has no option - equivalent to in the boot block, and - there is no provision to automatically select the internal - console and the serial console based on the presence of - the keyboard. - - - - - Caveats - - While most systems will boot without a keyboard, quite a - few will not boot without a graphics adapter. Machines with - AMI BIOSes can be configured to boot with no graphics adapter - installed by changing the graphics adapter - setting in the CMOS configuration to Not - installed. - - However, many machines do not support this option and will - refuse to boot if there is no display hardware in the system. - With these machines, leave some kind of graphics card plugged - in, even if it is just a junky mono board. A monitor does not - need to be attached. One might also try installing an AMI - BIOS. - +