l4-hackers Digest, Vol 54, Issue 9

Adam Lackorzynski adam at os.inf.tu-dresden.de
Wed Oct 17 23:15:48 CEST 2007

On Wed Oct 17, 2007 at 10:24:44 +0800, ¶¡Ó¨ wrote:
> > > the init=/bin/sh option in my command line ,but the keyboard isn't
> > working
> > > as before.The attachment is my l4linux's configuration file.Thanks a lot
> > for
> > > you help!
> >
> > So, looking at the config file, you neither have VGA_CONSOLE switched on
> > nor L4_FB_DRIVER. So how does your setup look like? I guess that's why
> > you're actually not seeing anything really useful on the screen. So how
> > about enabling VGA_CONSOLE?
> >
> >
> > Adam
> > --
> > Adam                 adam at os.inf.tu-dresden.de
> >   Lackorzynski         http://os.inf.tu-dresden.de/~adam/
>     I hava enabled the VGA_CONSOLE,and could saw some chang when
> starting,just like some words's color turned  normal,but the keyboard didn't
> working sitll.Then I enable the L4_FB_DRIVER,but it can't compile right,the
> error message like this:
> arch/l4/kernel/main.c:80:5: warning: #warning WARNING: L4FB enabled and also
> arch/l4/kernel/main.c:81:5: error: #error WARNING: This is usually not
> wanted.
> make[1]: *** [arch/l4/kernel/main.o] error 1
> make: *** [arch/l4/kernel] error 2
> and I used ubuntu-6.06  with gcc version gcc-4.0.3.
> There seems some problem in my configuration,but I can't  solve it. Could
> you show me with your l4linux config file?

I would really like that you understand what's going on. Let me explain.

Every system we consider here has devices. Those devices are your disk,
your keyboard, your monitor, your mouse etc. Each device needs some
software which knows this particular device and can drive it, thus it's
called a driver. A device can only driven by _exactly_ one driver at a
time. This is an important point.

Now, concerning display and key-input, L4Linux and the underlying L4
system can be configured in different ways.
  - direct access
  - console use
For 'direct access' L4Linux will drive the keyboard and mouse controller
and will control the screen (e.g. VGA). And only L4Linux will do that.
No one else. For the configuration of L4Linux this means that one needs
to enable the keyboard and mouse controller driver and the VGA driver.

For console use, the l4con or DOpE is controlling the keyboard and mouse
controller and the screen. And only l4con/DOpE is controlling the
keyboard/mouse/screen. No one else. For the configuration of L4Linux
this means that L4Linux does not need any keyboard/mouse driver nor any
VGA driver. It _just_ needs the l4fb driver (it also does input
So this is either or. Never both. 

And this is what the above error message wants to say you. You have the
l4fb driver enabled (L4_FB_DRIVER) and also the driver for the
keyboard/mouse controller and/or the VGA driver. And this does not fit

Please consider this when configuring your L4Linux.

Please also consider updating your Ubuntu, gcc-4.0 is ancient nowadays.

Adam                 adam at os.inf.tu-dresden.de
  Lackorzynski         http://os.inf.tu-dresden.de/~adam/

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