Re: PS2 Input Core Support

[Petr Vandrovec]

On 18 Jul 02 at 14:58, Vojtech Pavlik wrote:
> On Thu, Jul 18, 2002 at 12:17:51PM +0200, Petr Vandrovec wrote:
> 
> > > Cool! Anyone send me a patch? ;)
> > 
> > Been there, done that... and unfortunately, my WOP35 insist on
> > taking first 6 bytes as PS/2->ImPS/2 sequence, and rest as normal
> > DPI settings. I tried it in reverse order, and couple of permutations,
> > but it still returns ExPS/2 id. I tried also other sequences from
> > gm_psauxprint-0.01, but I found nothing interesting, except that
> > mouse definitely does not support MS PNP id.
> > 
> > Answer from A4Tech support was that mouse is not supported under Linux,
> > and that I should use Windows and verify that mouse is properly connected.
> > So I'm on the best way to the command line switch, I think. Google
> > find couple of problem reporters, but nobody found detection method :-(
> 
> Well, it should be possible to snoop the mouse data off the wire using
> a slightly modified parkbd.c module on a different machine and a split
> PS/2 mouse cable ...

Problem is that A4Tech driver does not care. It just interprets incoming
data in the way I described: +-1 is vertical move, +-2 is horizontal,
0 is no move, and everything else is ignored... This is A4Tech's 
interpretation of ImPS/2 and ExPS/2 protocols.

So we can either assume (like GPM does) that wheel movement can be
only +-1, and so we can safely assume that +-2 is horizontal move,
and then everything is fine, or we need some option which will affect
mouse driver behavior.

All my (A4Tech...) PS/2 wheel mouse report wheel movement only +-1 even
with 10Hz sample rate, but I do not think that my mouses are representative
sample of available ExPS/2 implementations.
                                            Petr Vandrovec