[Qemu-devel] Re: Serial Console / NoGraphic

[Clemens Kolbitsch]

On Tuesday 25 September 2007 12:04:17 Clemens Kolbitsch wrote:
> hi!
> i've been trying around for quite some time now trying to start qemu
> without the graphic screen... can someone tell me exactly what I'm supposed
> to do??
>
> i want to redirect the output of my i386 debian linux to my host-console
> (also a i386 debian) to fully see the output of a kernel panic (see
> previous messages i have posted).
>
> i'm starting qemu:
>
> qemu -hda myimage -boot c -kernel-kqemu -kernel mykernel -initrd
> myinitrd -append "root=/dev/hda1 console=/dev/ttyS0" -nographic
>
> after tons of trial-and-error i finally got my system to boot, however, the
> login-screen is not displayed (i see all output of the starting system up
> until the ">>login:"). how do i connect to the serial line now to get to
> the login??
>
> i have tried minicom, however that seems to just hang :-(
>
> should i use (tell qemu to use) a different "virtual" serial console?? how
> to i start minicom correctly?? could you give me the parameter set you guys
> are using for
> 1.) qemu
> 2.) connector (minicom???)
> 3.) what i have to enable inside my guest-system (i have checked
> that /etc/securetty include ttyS0 already)
>
> any help will - as always - be greatly appreciated!!
> thanks :-)

hi!
i finally found out that it was all just a configuration problem inside my 
guest :-)

for anyone having the same problem: 

qemu myimage -serial stdio -nographic

is totally sufficient as long as you tell linux to start getty listening on a 
serial console (make sure that GRUB tells your kernel to 
include "console=/dev/ttyS0").

in my case (a newer debian system) this was adding a file to
/etc/event.d/ called "ttyS0"

containing the line

/sbin/getty -L /dev/ttyS0 38400 vt100

maybe it helps someone :-)