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* Re: serial console and kernel 2.4
@ 2001-07-30 15:20 James Bottomley
  2001-07-30 15:37 ` christophe barbé
  0 siblings, 1 reply; 16+ messages in thread
From: James Bottomley @ 2001-07-30 15:20 UTC (permalink / raw)
  To: christophe barbé; +Cc: linux-kernel

> I recently upgraded a linux box to the kernel 2.4.4 (from 2.2.18).
> This box has no display and use the serial console. Since the upgrade
> I can see the boot output on the remote console but I can't use the
> keyboard. Each time I press a key, an interrupt is seen by the
> no-display machine but no char appears in the console.  Today I've
> upgraded an another box to 2.4.7 with a similar setup and I've the
> same problem.

> Is there something that I'm missing ? (something new with the kernel
> 2.4 that is required for a serial console that was not required with
> the 2.2 ?)

I hate to send an email which says "it works for me", but it does (all the way 
up to 2.4.7).

However, one of the things to remember about the serial console is that it is 
primarily designed for *output*.  If you see the boot messages, then it's 
doing its job correctly.  Things like kdb and sysrq can accept input from the 
serial console, but usually only if something else (like getty) has opened it 
first.

My setup (on RedHat 7.1) looks like this

In /etc/lilo.conf

# make lilo output to serial console
serial=0,9600n8

# for each kernel add this line
        append="console=ttyS0,9600n8 console=tty0"

Note, the above append causes /dev/console to be /dev/tty0 (the virtual 
console).  If you want to see all the boot messages you need /dev/ttyS0 to be 
/dev/console and you should reverse the two console statements in this line.

In /etc/inittab:

S:0123456:respawn:/sbin/mingetty --noclear ttyS0

With this setup I can activate sysrq and kdb from the serial console.

Note also that different distributions have different ways of handling the 
system console; you might also have to disable the special distribution 
handling on a non-RedHat system.

James Bottomley



^ permalink raw reply	[flat|nested] 16+ messages in thread
* Re: serial console and kernel 2.4
@ 2002-01-16 14:29 Eric Lamarque
  0 siblings, 0 replies; 16+ messages in thread
From: Eric Lamarque @ 2002-01-16 14:29 UTC (permalink / raw)
  To: linux-kernel

From: christophe barbé (christophe.barbe@lineo.fr)
Date: Mon Jul 30 2001 - 09:54:53 EST 
> I recently upgraded a linux box to the kernel 2.4.4 .
> Since the upgrade I can see the boot output on the remote console
> but I can't use the keyboard

It seems that I experiment the same problem: I've some Compaq machine
that I control remotely with the serial console.

It always runs 2.4.x kernel and all runs fine.

I just replace the machine by a newer one and experiment the same problem
as you. It seems to me that Linux send CTRL-S on the serial line.

To check that this is the real problem, I use rlogin to access the machine
and send CTRL-Q to the Linux console: it does the trick.
( # echo -e "\021" > /dev/console )

I trace the problem to be the arch/i386/kernel/dmi_scan.c function:
DMI is a set of structures to get information about the machine.
It is the one that print "Board Version:.." at boot time.

I'll check at http://www.ibm.com/products/surepath/other/smbios.html to
know the type of such data. "Board Version" must be a string (I assume with
printable character).

My problem is that "Board Version" is printed as "Board Version: 0x14 0x13 *."
where 0x13 is CTRL-S.

Does the kernel contains a mechanism to avoid console printing of DMI information?
(If not, we could maybe add it in function dmi_scan.c:dmi_save_ident()).

Eric.

^ permalink raw reply	[flat|nested] 16+ messages in thread
* serial console and kernel 2.4
@ 2001-07-30 14:54 christophe barbé
  2001-07-30 15:18 ` baettig
                   ` (2 more replies)
  0 siblings, 3 replies; 16+ messages in thread
From: christophe barbé @ 2001-07-30 14:54 UTC (permalink / raw)
  To: lkml

I recently upgraded a linux box to the kernel 2.4.4 (from 2.2.18). This box
has no display and use the serial console. Since the upgrade I can see the
boot output on the remote console but I can't use the keyboard. Each time I
press a key, an interrupt is seen by the no-display machine but no char
appears in the console. 
Today I've upgraded an another box to 2.4.7 with a similar setup and I've
the same problem.

Is there something that I'm missing ? (something new with the kernel 2.4
that is required for a serial console that was not required with the 2.2 ?)

Is sombody else experienciong the same problem ?

Christophe


-- 
Christophe Barbé
Software Engineer - christophe.barbe@lineo.fr
Lineo France - Lineo High Availability Group
42-46, rue Médéric - 92110 Clichy - France
phone (33).1.41.40.02.12 - fax (33).1.41.40.02.01
http://www.lineo.com

^ permalink raw reply	[flat|nested] 16+ messages in thread
end of thread, other threads:[~2002-01-16 14:30 UTC | newest]

Thread overview: 16+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2001-07-30 15:20 serial console and kernel 2.4 James Bottomley
2001-07-30 15:37 ` christophe barbé
2001-07-30 15:53   ` Stuart MacDonald
2001-07-30 16:21     ` christophe barbé
2001-07-30 16:55       ` Chris Wedgwood
2001-07-30 20:36         ` Thomas Duffy
2001-07-30 21:41           ` Chris Wedgwood
2001-07-30 22:24             ` Miquel van Smoorenburg
2001-07-31  7:51               ` christophe barbé
  -- strict thread matches above, loose matches on Subject: below --
2002-01-16 14:29 Eric Lamarque
2001-07-30 14:54 christophe barbé
2001-07-30 15:18 ` baettig
2001-07-30 15:33   ` christophe barbé
2001-07-30 15:19 ` Steve Hill
2001-07-30 20:43 ` Fabrice Gautier
2001-07-30 20:59   ` Miquel van Smoorenburg

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