[E3-hacking] [RFC][PATCH 4/5] input: serio: add support for Amstrad Delta serial keyboard port

Janusz Krzysztofik jkrzyszt at tis.icnet.pl
Mon Dec 14 00:11:34 GMT 2009

Hi Dmitry,

Sunday 13 December 2009 00:20:03 Dmitry Torokhov napisał(a):
> atkbd is supposed to support PS/2 devices speaking AT keyboard protocol.
> We also do support such devices behind dumb controllers that do not
> allow querying the device but we expect those to at least produce the
> standard scancodes.

As far as I can understand, using the atkbd driver is not a good idea in this 
case because of the keyboard not producing standard scancodes, correct?

Isn't the hpps2atkbd.h provided keycode table an already supported way of 
introducing exceptions to this standard scancodes requirement? Why couldn't 
this method be reused here?

What I am afraid of is if the driver supposed to be created instead wouldn't 
require reiplementing most of the atkbd code.

> I would need to know a bit more about the gamepad, but so far I still
> think that current attempot of creating intermediate serio module which
> allows to use atkbd driver is not the proper solution.

I modified the serio driver to send exactly what it gets from the buffer and 
examined its output with serio_raw. The gamepad (can be connected 
simultaneously) appeared to send exactly the same scancodes as the keyboard 
did. I couldn't see how those might be destinguished whether coming from the 
keybord or from the gamepad. Thus, handling them both together as a single 
device would probably be the only option here.

With both devices connected and keys pressed simultaneously, errors occure at 
the lowest level: parity check failed, invalid stop bit, etc. I don't think 
it would be possible to do anything about this. But this also means that 
trying to query them in order to get a sensible response would probably be 
not reliable.

Any thoughts?


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