Date: Sun, 12 Jan 1997 15:00:02 -0800 (PST) From: j@uriah.heep.sax.de (J Wunsch) To: freebsd-bugs Subject: Re: docs/2455: no description "option COMCONSOLE" Message-ID: <199701122300.PAA29656@freefall.freebsd.org>
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The following reply was made to PR docs/2455; it has been noted by GNATS. From: j@uriah.heep.sax.de (J Wunsch) To: gnats-admin@freefall.freebsd.org Cc: yoshiaki@kt.rim.or.jp Subject: Re: docs/2455: no description "option COMCONSOLE" Date: Sun, 12 Jan 1997 11:53:17 +0100 > In Handbook's section 5.3.6, > "You must choose one of these two console types (sc0 or vt0) ". But Neither of this is correct. You are no longer forced to even chose a console driver, the system can also run without a console now. The entire sentence has never been fully correct, since there was always the possibility to make the `sio' driver the console. > I experiment in 2.2-BETA_A system. If I use serial console, I have > not need console driver. (Well, this _is_ your console driver then. :) > In 2.2 BETA including sc0 system do not > hang-up with no video card system. That used to be broken for some time, since sc0 didn't react correctly if its probe failed. (I think the probe never failed at all.) > But if I include 'option COMCONSOLE', I must cuaa0 or ttyd0 serial > console to boot system. This can be changed by even more obscure options, as well as the port speed. > /etc/ttys > cuaa0 "/usr/libexec/getty std.9600" vt100 on secure > > To turn on getty cuaa0 or ttyd0 MUST need ! Not really. :) Only if you wanna log into your console. It runs perfectly as a console-only device without a getty on it. I.e., you'll see the syslog messages there, and if you've configured your DDB with BREAK_TO_DEBUGGER, you can single-step the entire system from there. > I wand 'option COMCONSOLE' description in Handbook. No, this option is deprecated. The bootblocks can perfectly pass down the consoleness of the serial port to the kernel, and the kernel will then prefer the sio0 driver over sc0 or vt0 for the console. (Hopefully, the sio0 driver is configured at all. ;) There are various methods to cause the bootblocks switching to a serial console: . Typing -h on the currently active boot console toggles the console between graphics and serial device (and proceeds to boot). . Setting BOOT_FORCE_COMCONSOLE in /etc/make.conf causes the bootblocks to be built with a forced serial console; this is rather similar to the kernel option COMCONSOLE except that you get already the boot prompt itself on the serial console, so you can enter any boot options. . Setting BOOT_PROBE_KEYBOARD_LOCK will make the decision depend upon the presence of a PC keyboard, but is unfortunately known to hang some machines since the BIOS doesn't provide us with a hook to fetch its probe result. . Setting BOOT_PROBE_KEYBOARD_LOCK makes the decision dependant from the state of the keyboard lock switch. All these methods are preferred over the kernel option (which btw. _is_ documented in LINT), since they allow to manipulate the boot process also from the serial console. -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)
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