evden and horizontal wheel

Ander Conselvan de Oliveira ander at c3sl.ufpr.br
Mon Oct 6 07:41:24 PDT 2008


Hello,

I have a user reporting his horizontal wheel is inverted using the evdev input 
driver. If I understand correctly, evdev handles positive values as "to the 
right" and negative as "to the left":

            case REL_HWHEEL:
                if (value > 0)
                    PostButtonClicks(pInfo, wheel_right_button, value);
                if (value < 0)
                    PostButtonClicks(pInfo, wheel_left_button, -value);
                break;

But the, somewhat recent, kernel commit 
740f370dc61dc478d891d7d47660bb3ae39ddb4f, by Dan Nicholson states:

"Some Logitech mice have a tilt wheel which register as HWHEEL buttons. The 
events are positive for a click to the right and negative for a click to the 
left. Applications expect the opposite, though."

Since I have no mice with horizontal scroll wheels, I have no idea what is the 
correct way to handle this.

Thanks,
Ander



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