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

[Andrew Morton <akpm@osdl.org>]

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.