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SubjectRe: Input issues - key down with no key up
On Thu, 21 Aug 2003, Andries Brouwer wrote:

> > Hmm, that would make some sense, but how does it work when an external
> > keyboard is attached?
> Usually the keyboard and mouse commands are sent to all attached
> keyboards resp. mice. Thus, with an internal keyboard that only
> knows about Set 2 and an external keyboard that also knows about
> Set 3 you can change the kbds to Set 3. Now the internal one is
> dead, but the external one functions.

I meant: how does the translation work if there is only a single onboard
controller that does scanning of the embedded keyboard and presents set #1
of codes directly? But after a bit of thinking I suppose it does support
translation for an external keyboard (which presents set #2 by default and
a lot of PC software expects set #1) and probably a pass-through mode for
it as well.

What the big fault of all these limited implementations is, there is no
reliable way to query what is supported. If a device does not support
mode switching or a particular mode, it should NAK a command that does it,
or at least report the original mode if queried afterwards. Another
possibility is to return a different device ID -- IBM chose a single value
of 256 possible for its PS/2 keyboards -- why couldn't the incompatible
others have chosen something different, sigh?...

+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+ e-mail:, PGP key available +

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