Linux console at boot

Linux console at boot

[George Bonser]

Is there any way to stop the console scrolling during boot? My reason
for this is I am trying to troubleshoot a boot problem with
2.4.18-pre7 and I would like to give a more useful report than "it
won't boot" but the screen outputs information every few seconds and I
can't "freeze" the display so I can copy down the initial error(s).

This is an Intel unit using the standard console (not serial console).
pre7 will not boot but pre6 boots every time.

RE: Linux console at boot

[George Bonser]

Not until after it boots and it never boots. Actually, the problem is
it never sees the disk.

I need to stop the bootup process or somehow hang the screen. Scroll
lock and xoff (^S) do not do anything.


> you can get this info via "dmesg"
>
> --
> timothy.covell@ashavan.org.

Re: Linux console at boot

[Brendan J Simon]

Timothy Covell wrote:

>On Thursday 24 January 2002 23:05, George Bonser wrote:
>
>>Is there any way to stop the console scrolling during boot? My reason
>>for this is I am trying to troubleshoot a boot problem with
>>2.4.18-pre7 and I would like to give a more useful report than "it
>>won't boot" but the screen outputs information every few seconds and I
>>can't "freeze" the display so I can copy down the initial error(s).
>>
>>This is an Intel unit using the standard console (not serial console).
>>pre7 will not boot but pre6 boots every time.
>>
Try <ctrl>s to stop the display scrolling and <ctrl>q to restart it.

Regards,
Brendan Simon.

RE: Linux console at boot

[M. Edward Borasky]

If all else fails, try a scan converter and a VCR with a decent freeze-frame
capability.

M. Edward Borasky
znmeb@borasky-research.net
http://www.borasky-research.net/

> -----Original Message-----
> Is there any way to stop the console scrolling during boot?

RE: Linux console at boot

[George Bonser]

>
>
> If all else fails, try a scan converter and a VCR with a
> decent freeze-frame
> capability.
>

Well, I imagine if this problem gets released with 2.4.18 there will
probably be someone
that has such a rig already to troubleshoot it :-)

If nobody else runs into it, I will likely hook it up with a serial
console and record the output on a different machine. There were
plenty of SCSI changes in pre7. I backed out the rather harmless
looking change in the aic7xxx driver with no luck so I am guessing it
was something in the generic scsi stuff that broke the ability to find
the disk.

Re: Linux console at boot

[Kenneth MacDonald]

>>>>> "George" == George Bonser <george@gator.com> writes:

    George> Is there any way to stop the console scrolling during
    George> boot? My reason for this is I am trying to troubleshoot a
    George> boot problem with 2.4.18-pre7 and I would like to give a
    George> more useful report than "it won't boot" but the screen
    George> outputs information every few seconds and I can't "freeze"
    George> the display so I can copy down the initial error(s).

Does keeping SHIFT-PAGEUP help?  It'll warp back to the bottom on
output, but should give you enough time to get what you need.  Try
taking a photo of the screen while pressing that key combination too.

-- 
Kenny

ADML Support, EUCS, The University of Edinburgh, Scotland.

Re: Linux console at boot

[Timothy Covell]

On Thursday 24 January 2002 23:05, George Bonser wrote:
> Is there any way to stop the console scrolling during boot? My reason
> for this is I am trying to troubleshoot a boot problem with
> 2.4.18-pre7 and I would like to give a more useful report than "it
> won't boot" but the screen outputs information every few seconds and I
> can't "freeze" the display so I can copy down the initial error(s).
>
> This is an Intel unit using the standard console (not serial console).
> pre7 will not boot but pre6 boots every time.
>

you can get this info via "dmesg"

-- 
timothy.covell@ashavan.org.

Re: Linux console at boot

[Timothy Covell]

On Thursday 24 January 2002 23:59, Brendan J Simon wrote:
> Timothy Covell wrote:
> >On Thursday 24 January 2002 23:05, George Bonser wrote:
> >>Is there any way to stop the console scrolling during boot? My reason
> >>for this is I am trying to troubleshoot a boot problem with
> >>2.4.18-pre7 and I would like to give a more useful report than "it
> >>won't boot" but the screen outputs information every few seconds and I
> >>can't "freeze" the display so I can copy down the initial error(s).
> >>
> >>This is an Intel unit using the standard console (not serial console).
> >>pre7 will not boot but pre6 boots every time.
>
> Try <ctrl>s to stop the display scrolling and <ctrl>q to restart it.
>
> Regards,
> Brendan Simon.
>

If you are using test kernels, then you should be prepared to use
a serial console, IHMO.   (I use them often anyhow inasmuch as I
don't have big KVM switch and only one monitor)   

Also, if it gets to the init part and you're using redhat, you can 
interrupt the boot sequence (step-by-step mode) and then try to
page up.    

Just my two cents.

-- 
timothy.covell@ashavan.org.

Re: Linux console at boot

[Keith Owens]

On Thu, 24 Jan 2002 21:05:45 -0800, 
"George Bonser" <george@gator.com> wrote:
>Is there any way to stop the console scrolling during boot? My reason
>for this is I am trying to troubleshoot a boot problem with
>2.4.18-pre7 and I would like to give a more useful report than "it
>won't boot" but the screen outputs information every few seconds and I
>can't "freeze" the display so I can copy down the initial error(s).

Serial console is the best.  If you can't do that, add a delay after
each set of console output.  Tweak 100000000 to get a suitable delay.

Index: 17.1/kernel/printk.c
--- 17.1/kernel/printk.c Tue, 11 Dec 2001 09:58:50 +1100 kaos (linux-2.4/j/48_printk.c 1.1.2.2.7.1.2.3 644)
+++ 17.1(w)/kernel/printk.c Sat, 26 Jan 2002 21:30:53 +1100 kaos (linux-2.4/j/48_printk.c 1.1.2.2.7.1.2.3 644)
@@ -373,6 +373,7 @@ static void call_console_drivers(unsigne
 		}
 	}
 	_call_console_drivers(start_print, end, msg_level);
+	{ int i; for (i = 0; i < 100000000; ++i) ; }
 }
 
 static void emit_log_char(char c)

RE: Linux console at boot

[George Bonser]

Well I have been all through the incremental from pre6 to pre7 and
dont see anything obvious that would cause it not to see the disks.
Nobody else has complained of it ... so weird.

>
> Serial console is the best.  If you can't do that, add a delay after
> each set of console output.  Tweak 100000000 to get a
> suitable delay.
>
> Index: 17.1/kernel/printk.c
> --- 17.1/kernel/printk.c Tue, 11 Dec 2001 09:58:50 +1100
> kaos (linux-2.4/j/48_printk.c 1.1.2.2.7.1.2.3 644)
> +++ 17.1(w)/kernel/printk.c Sat, 26 Jan 2002 21:30:53 +1100
> kaos (linux-2.4/j/48_printk.c 1.1.2.2.7.1.2.3 644)
> @@ -373,6 +373,7 @@ static void call_console_drivers(unsigne
>  		}
>  	}
>  	_call_console_drivers(start_print, end, msg_level);
> +	{ int i; for (i = 0; i < 100000000; ++i) ; }
>  }
>
>  static void emit_log_char(char c)

RE: Linux console at boot

[George Bonser]

The machine in question appears to have an Intel L440GX motherboard.
The firmware is probably out of date so I am going to flash it current
before complaining any more about it. Strange that pre6 works every
time but pre7 fails consistantly every time though.




>
> Well I have been all through the incremental from pre6 to pre7 and
> dont see anything obvious that would cause it not to see the disks.
> Nobody else has complained of it ... so weird.

Re: Linux console at boot

[Geert Uytterhoeven]

On Thu, 24 Jan 2002, George Bonser wrote:
> Is there any way to stop the console scrolling during boot? My reason
> for this is I am trying to troubleshoot a boot problem with
> 2.4.18-pre7 and I would like to give a more useful report than "it
> won't boot" but the screen outputs information every few seconds and I
> can't "freeze" the display so I can copy down the initial error(s).
> 
> This is an Intel unit using the standard console (not serial console).
> pre7 will not boot but pre6 boots every time.

On Amiga (m68k and PPC) we have a `debug=mem' option that will write all kernel
messages to a 256 KiB block (marked with a magic number) of Chip RAM. If the
system crashes early, you can reboot into AmigaOS and run a special utility
that finds the 256 KiB block (Chip RAM is not completely erased on reboot) and
extracts the messages.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds

Re: Linux console at boot

[Bradley D. LaRonde]

----- Original Message -----
From: "Geert Uytterhoeven" <geert@linux-m68k.org>
To: "George Bonser" <george@gator.com>
Cc: "Linux Kernel Development" <linux-kernel@vger.kernel.org>
Sent: Tuesday, February 12, 2002 3:52 AM
Subject: Re: Linux console at boot


> On Thu, 24 Jan 2002, George Bonser wrote:
> > Is there any way to stop the console scrolling during boot? My reason
> > for this is I am trying to troubleshoot a boot problem with
> > 2.4.18-pre7 and I would like to give a more useful report than "it
> > won't boot" but the screen outputs information every few seconds and I
> > can't "freeze" the display so I can copy down the initial error(s).
> >
> > This is an Intel unit using the standard console (not serial console).
> > pre7 will not boot but pre6 boots every time.
>
> On Amiga (m68k and PPC) we have a `debug=mem' option that will write all
kernel
> messages to a 256 KiB block (marked with a magic number) of Chip RAM. If
the
> system crashes early, you can reboot into AmigaOS and run a special
utility
> that finds the 256 KiB block (Chip RAM is not completely erased on reboot)
and
> extracts the messages.

Also, printk already writes (appends) to a smaller-but-sufficiently-large
buffer - log_buf.  When debugging early boot crashes, I frequently look up
the address of log_buf in System.map and dump that area of memory from my
boot monitor or JTAG prompt.

Regards,
Brad

RE: Linux console at boot

[Alexander Sandler]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="x-user-defined", Size: 784 bytes --]

Hi.

> > > Is there any way to stop the console scrolling during 
> boot? My reason
> > > for this is I am trying to troubleshoot a boot problem with
> > > 2.4.18-pre7 and I would like to give a more useful report than "it
> > > won't boot" but the screen outputs information every few 
> seconds and I
> > > can't "freeze" the display so I can copy down the initial 
> error(s).
> > >
> > > This is an Intel unit using the standard console (not 
> serial console).
> > > pre7 will not boot but pre6 boots every time.

You may try to make to make a system to sleep for a while (until you'll
press something for instance) from the initrd image. Take a look at the
Documentation/initrd.txt (???).
Depending on the message you are interested to see, this should help.

Alexandr Sandler.

RE: Linux console at boot

[Davidovac Zoran]

> > > > Is there any way to stop the console scrolling during
> > boot? My reason
> > > > for this is I am trying to troubleshoot a boot problem with
> > > > 2.4.18-pre7 and I would like to give a more useful report than "it
> > > > won't boot" but the screen outputs information every few

press and hold SHIFT + PAGEUP

once you login

you could see these messages with

dmesg

Z