Re: Boot hangs with kbd unplugged

[markus@infoscape.com]

Hi Heinrich,

 > I am using etherboot 3.2 and mknbi-linux 0.7.1(netboot). Works fine!
 > However, if i want to operate a Linux PC without keyboard (printserver),
 > the boot process hangs after the message
 > 
 > 	Linux Net Boot Image Loader

This was a known error in prior releases of etherboot; it should be
fixed in release 3.2. You are experiencing problems with a buggy
keyboard controller. Most machines work just fine without keyboards,
but are stuck with a defective motherboard. The problem occurs when
etherboot (or Linux) tries to enable the gate A20, which is neccessary 
to access any memory location above 1MB. This is done by programming
the keyboard controller. Ideally, it should be independant of whether
a keyboard is attached, but with your machine the controller does not
acknowledge the operation if there is no keyboard. You could try
playing around with your BIOS configurations. If there is any mention
of the word "keyboard" or "gate A20", then change these options.

 > As soon as i plug in the keyboard, the process continues with
 > 
 > 	Uncompressing Linux...done
 > 	Now booting the kernel

This almost looks as if it was Linux, that is waiting for the keyboard 
controller. You might need to patch the Linux kernel. Take a look at
the end of "src/misc.c" in the etherboot 3.2 source tree. There is a
timeout of 1s in the empty_8042() code. You will probably have to port 
this code into the appropriate code in the Linux starter. Check around 
line 640 in /usr/src/linux/arch/i386/boot/setup.S; after applying this 
patch, you will also have to make certain, that the gate A20 is
enabled by some other means. If you are lucky, this can be done from
your system BIOS. There might be an option labled "fast gate A20" that 
could have some effect...

 > Is the Boot Image Loader waiting for any keyboard input?
 > If so, can this be disabled?

If none of the above helps, you will have to buy some cheap 20,-DM
keyboard that you keep attached to your machine.


Markus

-- 
Markus Gutschke                         Internet: markus@infoscape.com
Infoscape, Inc                          Phone:    +1-415-537-3778
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San Francisco, CA 94105

Disclaimer: The above message represents my personal opinion; It does
            not constitute an offical statement by Infoscape!

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