Re: PMax LK201 Autorepeat

[Mats O Jansson <maja@cntw.com>]

On Mon, 9 Mar 1998, CyberPeasant wrote:

> I recently removed the LK-201 keyboard from my DS3100/OpenBSD 2.1 machine
> for cleaning. Being a rash sort, I did this in the middle of an X session.
> 
> While the keycaps etc. were drying, I plugged in another LK-201, also
> "hot swapping", i.e. without powering down the machine or even stopping X.
> (I am fearless.)

This is not a good idea. The keyboard is initialized by the kernel when
booted. Swaping keyboard without reboot can give unexpected results,
this because the keyboard has not been initialized to a known state.

> To my surprise, the spare LK-201 exhibited the following miraculous
> behavior:
> 
> 	Up and Down Arrow autorepeat worked!  It took two presses (both
> 	gave keyclicks) of Up or Down Arrow to get one response when
> 	not-autorepeating.  Return behaved the same, both with respect
> 	to autorepetition, and the need to press twice when single keying.
> 
> 	Xev showed the expected response for these keys under autorepeat,
> 	/and, curiously/, showed the Return event for the first 
> 	(ineffective in an xterm) press of those weird double-keyings.
> 	
> 	This "double keying" needs clarification:  To get N Returns,
> 	I had to press the Return key N+1 times.
> 
> The other LK-201 has always has shown the pesky no up/down/return
> autorepetition bug, which many have remarked. 
> 
> In the spirit of science, I stopped X, and lo, the autorepetitions worked
> also with the console. The "double keying" was /gone/.  Weirder and weirder.
> 
> I restarted X : the keyboard reverted to the old "no autorepeat up/down
> mode". "Double press" on those keys was gone.
> 
> Hmm.  Evidently the LK-201 is programmable? Has some kind of /modes/
> it can be sent?  And is being sent the /wrong ones/ by X?

Since I havn't looked at the X code I don't know how it's handled. But 
/sys/arch/pmax/dev/lk201.[ch] is how OpenBSD does it.

> Factoid: the LK-201 which exhibited the "good" behavior, /had never been
> plugged into a Pmax before/ -- it is salvage from a Rainbow.
> 
> Comments, gentlemen?
> 
> Dave 
> -- 
> PGP public key:  finger djv@bedford.net
> 			 --== Old age sucks. ==--
> 

-moj

------------------------------------------------------------------------------
Mats O Jansson. Managing AIX systems at, but not speaking for:
CelsiusTech AB, Jaerfaella, Sweden. You may not add me to a commercial
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"Something must be wrong when a goldfish commit suicide" Godley & Creme