Re: [PATCH] mousedev: Fix scrollwheel thingy on IBM ScrollPoint mice

[Dmitry Torokhov <dtor_core@ameritech.net>]

On Tuesday 26 October 2004 07:11 pm, Andrew Morton wrote:
> Kim Holviala <kim@holviala.com> wrote:
> >
> > The scrollwheel thingy (stick) on IBM ScrollPoint mice returns extremely
> > aggressive values even when touched lightly. This confuses XFree which
> > assumes the wheel values can only be 1 or -1. Incidently, it also
> > confuses Windows' default mouse driver which proves the problem is in
> > the mouse itself.
> > 
> > This patch limits the scroll wheel movements to be either +1 or -1 on
> > the event -> emulated PS/2 level. I chose to implement it there because
> > mousedev emulates Microsoft mice but the real ones almoust never return
> > a bigger value than 1 (or -1).
> > ...
> > +#ifdef CONFIG_INPUT_MOUSEDEV_WHEELFIX
> > +				if (value) { value = (value < 0 ? -1 : 1); }
> > +#endif /* CONFIG_INPUT_MOUSEDEV_WHEELFIX */
> 
> This is really not a thing which we can put behind compile-time config.
> 
> Can we come up with a fix which works correctly on all hardware?  If not,
> this workaround will need to be enabled by some sort of runtime detection.
> 

Unless someone (Vojtech?) has an objection I think we should always have
this workaround activated - after all mousedev provides legacy emulation
mostly for XFree/XOrg benefit anyway. Clients accessing data through evdev
will see the full picture regardless.

-- 
Dmitry