Re: [gtk-vnc-devel] [PATCH][RFC] Support for ExtendedKeyEvent client message

[Anthony Liguori <anthony codemonkey ws>]

Markus Armbruster wrote:
> Anthony Liguori <anthony codemonkey ws> writes:
>
>   
> > Not really.  PC key codes are well defined for one type of keyboard,
> > but are used by every keyboard.  I guess there's a 1-1 mapping of
> > Linux keycodes to PC keycodes.  I don't believe Linux keycodes are
> > richer than PC key codes though because PC key codes are what are
> > being generated from the actual keyboard.  By definition, there has to
> > be a PC key code for any given key while this isn't necessarily true
> > for Linux keycodes.
> >     
>
> There has to be a PC key code for every physical key on a PC keyboard.
>
> However, not every keyboard is a PC keyboard, and some of them have
> keys that that don't exist on PC keyboards.
>   

Well, I think this is our problem.  When I say, PC key code, I don't 
mean the codes assigned to keys on a PC101 keycode.  I mean any hardware 
keycode that is delivered through a PS/2 port.

GDK calls this a "hardware keycode" which is perhaps a better nomenclature.

Regards,

Anthony Liguori

> What's PC key code the code for a power key?  The Linux key code is
> KEY_POWER, easily looked up in linux/input.h.  If I read
> atkbd2_set2_keycode[] correctly, the PC key code is 0xB7, but I'm not
> sure.  I can't see KEY_LINEFEED, KEY_AGAIN, KEY_PROPS, KEY_UNDO,
> KEY_FRONT and many more in that table.  If there are PC key codes for
> these keys, I don't know how to find them.
>
>   
> > So I guess it really comes down to, what benefit would we get by using
> > Linux key codes?
> >     
>
> None, if PC key codes are at least as rich (which I doubt) and at
> least as well-defined (which I doubt too).
>
>   
> > Regards,
> >
> > Anthony Liguori
> >
> >     
> > > Linux input layer key codes are an encoding for the physical keys of
> > > any keyboard supported by Linux.
> > >
> > > It's easy to map from PC key codes to Linux input layer key codes and
> > > back.  The map doesn't depend on what keymap the user configured,
> > > because both encodings identify physical keys.  But Linux input layer
> > > key codes are a richer encoding.  What's the PC key code for
> > > KEY_POWER?
> > >
> > > Again, please excuse me if I talk nonsense, and try to use simple,
> > > short sentences in your reply %-}
> > >   
> > >