Keycodes >0xff

Jim Gettys Jim.Gettys at
Tue Jun 14 18:42:50 EEST 2005

Yes, keycodes are limited to 248 (8 codes are reserved for other uses).

We did not forsee any keyboards with more than 248 unique keys; you'll
need to use codes that are not otherwise in use.  So scancodes will need
mapping to keycodes in some fashion, rather than being one-to-one.

I challenge you to show me a keyboard with more than 248 actual keys on

Note that each keycode can have arbitrary keysyms associated with it.
					- Jim Gettys

On Tue, 2005-06-14 at 17:31 +0200, Michał Pytasz wrote:
> Hi,
> I'm new to this list, and not sure if it is the right place to ask my 
> question. Recently I prepared an additional keyboard layout for Creative 
> wireless desktop 8000 for X (and posted to bug 3514) but 
> there is one thing that makes me wonder. 
> Are the keycodes for X limited to 255? (one byte) If not how to add keys with 
> scancodes 278-280 (0x116-0x118) ? <linux/input.h> allows 9 bit keycodes (max 
> 0x1ff) this is the reason for my question, since in X, keys with scancodes 
> >255 remain dead, trying to add (in xkb/keycodes/xfree86) additional 
> scancodes and increasing maximum made all additional keys of the keyboard 
> dead. 

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