On Thu, 6 Apr 2000, Vojtech Pavlik wrote:
> > (ii) many laptops only support scancode mode 2.
>
> True. Many normal keyboards too. And other keyboards have broken Set 3,
> sending wrong scancodes for some keys, because the manufacturers didn't
> test their operation in this mode.
It's not the lack of mode #3 support that is the brokenness. The problem
is the fact at least some keyboards do positively ack the command to
switch into mode #3 but still remain in mode #2. If they rejected the
command it would be just OK.
Once I wrote a program that contained a keyboard driver to support all
three modes depending on a keyboard preset. Keyboards were autodetected
and if an XT or an AT keyboard was present it was used in its native mode
with all scancodes translated to their mode #3 equivalents through two
simple lookup tables. It worked very well unless a keyboard claimed to be
of a PS/2 type, acked the switch to mode #3 but then did not implement it.
This is how I learned this part of PC can be broken, too...
-- + Maciej W. Rozycki, Technical University of Gdansk, Poland + +--------------------------------------------------------------+ + e-mail: macro@ds2.pg.gda.pl, PGP key available +- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Fri Apr 07 2000 - 21:00:16 EST