Input Event Handling

Thorsten Wilms t_w_ at
Wed Apr 4 01:40:02 PDT 2007


I'm working on a concept that deals with mapping user input device 
events to actions. For this it would be better to know how input 
events are handled currently. Searched for a while, even had a look 
at the ICCCM but failed to get anything out of it.

I initialy though it would be roughly like this:
device -> driver->kernel -> userspace
If X is running:
device -> driver->kernel -> x-server -> WM -> app that has focus
Where events can be interpreted and not passed on on every level.

In a random IRC channel I have been told that events are not passed 
through the WM. But how can the WM intercept shortcuts, then?

With further thinking, input focus might happen on 3 levels:
widget, window, application. Right?

If I hit Alt-F1 to switch to the first console, is that shortcut 
interpreted by the kernel or the x-server?

Does the x-server anything special to receive all input events?

Does the kernel have a concept like input focus?

So please enlighten me about what way input events take, where 
they can be intercepted (shortcuts) and how input focus is 

Thorsten Wilms

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