[syslinux] Completely disable local keyboard input in Syslinux / Extlinux?

[Alexander Foken]

On 06.06.2011 19:20, H. Peter Anvin wrote:
> On 06/04/2011 12:55 PM, Alexander Foken wrote:
>> And I can't find a way to tell Syslinux / Extlinux to completely ignore
>> the local keyboard and use only the RS232 interface. "console 0"
>> suppresses only writing to the graphics card, but it does not disable
>> reading the local keyboard.
>>
>> Perhaps there is a way to (ab-)use the keymap feature, mapping all keys
>> to "no key pressed"?
>>
> If you give it an all-zero keymap (256 bytes of NULL) that is probably
> the effect you will get, I'm not sure.
I tried dd if=/dev/zero of=null.kbd bs=256 count=1, and added "kbdmap 
null.kbd" to extlinux.conf.

The 0xB6 chars in the RS232 output are gone, but extlinux seems to be 
busy discarding the fake keystrokes from the BIOS. It hangs at the 
"boot:" prompt, probably because even the discarded keystrokes stop the 
timeout counter and because handling the local keyboard seems to have 
priority over handling the input from RS232.

So, I added "totaltimeout 200" to make extlinux boot despite the 
discarded local input. The "boot:" prompt is still there, after more 
than 5 minutes, and it still does not handle RS232 input.
> The other option is to edit the source and remove the calls to the
> keyboard (INT 16h.)

That's what I wanted to avoid.

Alexander

-- 
Alexander Foken
mailto:alexander at foken.de  http://www.foken.de/alexander/