Re:Re: Q: Howto access the keyboard in a linux system without a graphics card ?

From: Richard B. Johnson (root@chaos.analogic.com)
Date: Mon Aug 26 2002 - 11:01:42 EST


On Mon, 26 Aug 2002, Kai-Boris Schad wrote:

> Am Montag, 26. August 2002 13:36 schrieben Sie:
> > On Mon Aug 26 2002 at 11:43, Kai-Boris Schad wrote:
> > > Hi !
> > >
> > > I'm trying to set up a small embedded system for gps receiving with a
> > > linux system. I want to have the system working without a graphics card
> > > - wich works well. The Problem I have at the moment is to access the
> > > keyboard without a graphics card, because the console driver does not
> > > start then ( Also a redirect doesn't work then :-( )
> > > Is there a way to access the keyboard in this case by a user program ?
> > > The system recognises the keyboard ( I think Kernel and init) and reacts
> > > if ctrl-alt-del is pressed.
> > >
> > > Thanks for your help !
> >
> > Why not boot and access it through a serial port? It is possible to
> > get the boot loader, kernel and console access through that, totally
> > headless and kdb-less. The howtos tell you how to it...
> >
> > > Kai
> >
> > Cheers
> > Tony
>
> O.k. Thanks for the comment, actually I was also thinking about this. The
> problem is that I cannot insert any additional serial ports or interfaces
> (hardware). I have a small PC(PC104 Dimensions) with two serial ports, one
> for a gps modul and the other for a packet radio modem. On the parallel port
> I have a LCD monitor. And a small numberblock keyboard connected to the
> keyboard connector. With the graphics card everything works fine - the
> problem is that I don't have any room for the card in the box and I really
> don't need it because of the lcd module (execept for the keyboard ;-)).
>
> Is there any way to tell the console/tty driver to start without a graphics
> card ?
> How does the system recognise the ctrl-alt-del ? (because this works anyway)
>
> Ok I think my task is very special but I wondered a bit because I didn't
> expect the console, or tty drivers to stop without the graphics card.
>
> I hope there is a solution for this ;-)
>
> Kai
>
> --
> Kai-Boris Schad
> University of Ulm, Germany
> Dept. of Electron Devices and Circuits
> Integrated Circuits in Communications
> Albert Einstein Allee 45
> 89069 ULM
>

In an embedded system I noticed that Linux assumes that the keyboard
is missing if it can't find a screen-card. I thought it strange, but
since I make my own 'init' anyway, I just put "console=null" as a start
parameter for all cases, even if there is a screen card. Within init I
find out what I/O exists (RS-232C, etc), and set that up for I/O and
controlling terminal. Basically, close(0,1,2), then try to open
/dev/console, if that fails, open /dev/ttyS0, etc...

Cheers,
Dick Johnson
Penguin : Linux version 2.4.18 on an i686 machine (797.90 BogoMips).
The US military has given us many words, FUBAR, SNAFU, now ENRON.
Yes, top management were graduates of West Point and Annapolis.

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