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SubjectRe: AT Keyboard (was: Helge Hafting vs. make menuconfig help)
On Tue, 2004-06-15 19:59:03 +0000, Karel Kulhavý <>
wrote in message <20040615195903.A7813@beton.cybernet.src>:
> > 4. From there, the key is propagated through tty and
> > console and ends up in your application. This application
> > might be X, which passes the key onto some program using X.
> I am insterested in the 4. itself.

This is from memory, some details may be wrong:

- The keyboard driver first determines what key the scancodes
belong to. If you press one single key, it may be sent as
multiple scancodes. The keyboard driver first has to assemble
these scancodes and make a decision from it (like "Key 'a'
pressed"). This information ('a' pressed down). is put into
Input API.
- Input API then prepares hands this key press to the TTY
- An application on the currently visible VT gets the 'a' (if it
didn't request raw scancodes. In this case, the TTY layer
*emulates* scancodes from the "'a' pressed down" event), and
the 'a' is also displayed on the VT (if echo'ing is switched


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