running a motherboard without a keyboard

Richard A. Smith richard at
Tue Nov 25 19:23:13 EST 2008

Guylhem Aznar wrote:

> I'm thinking about getting a USB-serial cable to connect to J1 ;
> meanwhile, I figured out I could use the gamepad, rotation button and
> the 4 game keys, along with blinking the leds, but looks like they are
> not working, while the power button is working fine.
> Is it due to the missing keyboard part? Is there a quick way to fix it?

The gamepad and gamebuttons are read by the EC and inserted into the 
keyboard stream as special keys.  Offhand I don't know what the kernel 
does when you boot and nothing responds to the keyboard reset.

The physical keyboard is not necessary for the EC to send up keyboard 
events but if nothing kernel side is servicing the keyboard IRQ then you 
won't get any data.

You can see if interrupts are getting serviced by:

  echo 1 > /sys/module/i8042/parameters/debug

and look at the kern.* debug stream.

You can also look at /proc/interrupts and see if the count for IRQ 1 is 
increasing after you press the buttons.

Richard Smith  <richard at>
One Laptop Per Child

More information about the Devel mailing list