Re: VTs and multiple keyboards

[Vojtech P. <vo...@su...>]

On Wed, Jun 07, 2000 at 10:03:49PM -0400, James Simmons wrote:
> 
> Now that I understand the way the keyboard <-> tty works like for ruby.
> 
> -------------------------------------------------------------------------
> 
> Ruby way for AT keyboards:
> 
> i8042.c -(raw)-> atkbd.c -(events)-> input.c -->
> >--(events)-> keyboard.c -(chars)-> tty
> 
> Ruby way for USB keyboards:
> 
> usb.c -(usb)-> hid.c -(events)-> input.c -->
> >--(events)-> keyboard.c -(chars)-> tty
> 
> -----------------------------------------------------------------------
> 
> The next question is can we have 
> 
>  i8042.c            usb.c  
>    |                  | 
>  (raw)              (usb) 
>    |                  |
>  atkbd.c            hid.c 
>    |                  |
>  (events)           (events)
>    |                  |
>    |                  |
>  input.c            input.c      
>    |                  |     
>    --------(events)-----------> keyboard.c -(chars)-> tty
> 
> I'm assuming only specific EV_KEY events get sent to keyboard.c. If
> keyboard.c only sees events coming in and we want to support multiple
> keyboards how are we going to tell the different keyboards apart? Wait I
> think I see how. We have
> 
> void kbd_event(struct input_handle *handle, unsigned int event_type, 
>                unsigned int keycode, int down)
> {
>         if (event_type != EV_KEY) return;
>         kbd_keycode(keycode, down);
>         tasklet_schedule(&keyboard_tasklet);
> }
> 
> In input_handle we have input_dev *dev which has a name string whcih I can
> use compare which keyboard it came from. I think? Ideas Vojtech.

Not just a name, you also have the idbus, idvendor, idproduct,
idversion, *number* variables in struct input_dev. I hope to add
tbus, tdev, tfunc or something like that to identify where the device is
in the bus topology.

When a keyboard (or other input device) is found, the kbd_connect
function is called. The function then looks at the device, and if it
likes it, it can open it and get events from it. In this (kbd_connect)
function, we should decide which VTs to bind that keyboard to initially. 

The handle struct also has a 'private' pointer, which can be used to
associate any private data with the handle struct, so we always know
what keyboard is that.

-- 
Vojtech Pavlik
SuSE Labs