[Qemu-devel] Re: Re: Scrolling console output (Ben Taylor) (Girish V)

[Girish V]

Message: 4
Date: Wed, 2 Apr 2008 11:58:08 -0400
From: "Girish V" <address@hidden>
Subject: [Qemu-devel] Scrolling console output
To: address@hidden
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       <address@hidden>
Content-Type: text/plain; charset="iso-8859-1"

Hello,

I am having the same question as asked in this thread
http://lists.gnu.org/archive/html/qemu-devel/2008-03/msg00399.html

I am trying to debug why my kernel crashes during the boot process. But some
of the error messages scroll of the target console, before I can see what is
happening.

For this, I would like to scroll the target console (My kernel crashes
before init begins - I have seen that once Init begins, I can scroll up the
target console using ctrl+PgUp - but before init begins the console canot be
scrolled).

I tried "qemu -hda image.img -m 512M -serial vc:1024x768" (to see if I could
set a bigger size for the console - so the messages wont scroll off the
target console)
but this fails with
"qemu: could not open serial device vc:1024x768"

I am running qemu 0.8.2 on ubuntu and 0.8.2 on fc6.

1) Is this "vc:AxB " option supported on this version - do I need to
upgrade?
2) I sthere any other way I can scroll up the target console.
3) Is there any other way to expand the target console?

Any help will be appreciated

Thanks.
Girish
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Message: 5
Date: Wed, 2 Apr 2008 12:07:17 -0400
From: "Ben Taylor" <address@hidden>
Subject: Re: [Qemu-devel] Scrolling console output
To: address@hidden
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On Wed, Apr 2, 2008 at 11:58 AM, Girish V <address@hidden> wrote:
> Hello,
>
> I am having the same question as asked in this thread
> http://lists.gnu.org/archive/html/qemu-devel/2008-03/msg00399.html
>
>  I am trying to debug why my kernel crashes during the boot process. But
> some of the error messages scroll of the target console, before I can see
> what is happening.

Given the fact that it crashes, I might be inclined to actually make the
console a real serial port, one of the virtual serial ports so you could
use a scrolling terminal to catch all the output.  Once you get the problem
fixed, then you can go back to the sdl console.




------------------------------

Thanks for the quick response. I was able to follow your tip. In order to get it working on FC6 I had to do the following.
1) Edit inittab to allow serial connections
2) Specified console=ttyS0 in the kernle line in the grub.conf

Then when I invoked qemu -hda img.img -nographic I could see the entire bootup messages on the terminal.

Girish