[PATCH xf86-input-libinput] Up the scroll dist value for touchpads

[Hans de Goede]

Hi,

On 04-03-15 06:00, Peter Hutterer wrote:
> For source FINGER and CONTINUOUS, the axis value is the same as relative
> motion - but scrolling in X usually doesn't have the same speed as finger
> movement, it's a lot coarser.
>
> We don't know ahead of time where we'll get the scroll events from. Set a
> default scroll distance of 15 and multiply any wheel clicks we get by this
> value.
>
> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
> ---
> 15 is more-or-less a magic value, it feels just right on my box here

Hmm, this is somewhat different from what we discussed in our mail conversation.

First of all the problem most users are reporting and I'm seeing myself is not
that mouse wheel scrolling is too slow (which this patch seems to imply), but
rather that finger scrolling is much too fast, see e.g.:

https://bugzilla.redhat.com/show_bug.cgi?id=1198467

What I understood from our discussion on this is that the idea for
mouse wheel scrolling was to emulate discrete-value number of button
4 / 5 clicks and let X do the translation into scrolling axis, giving
us the exact same scroll wheel speed as the evdev driver.

That and for finger scroll events actually make things slower by applying
a multiplication factor < 1.0 .

Regards,

Hans


>
>   src/libinput.c | 16 ++++++++++------
>   1 file changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/src/libinput.c b/src/libinput.c
> index 049c15b..5e616c8 100644
> --- a/src/libinput.c
> +++ b/src/libinput.c
> @@ -756,18 +756,22 @@ xf86libinput_handle_axis(InputInfoPtr pInfo, struct libinput_event_pointer *even
>
>   	axis = LIBINPUT_POINTER_AXIS_SCROLL_VERTICAL;
>   	if (libinput_event_pointer_has_axis(event, axis)) {
> -		if (source == LIBINPUT_POINTER_AXIS_SOURCE_WHEEL)
> +		if (source == LIBINPUT_POINTER_AXIS_SOURCE_WHEEL) {
>   			value = libinput_event_pointer_get_axis_value_discrete(event, axis);
> -		else
> +			value *=  driver_data->scroll_vdist;
> +		} else {
>   			value = libinput_event_pointer_get_axis_value(event, axis);
> +		}
>   		valuator_mask_set_double(mask, 3, value);
>   	}
>   	axis = LIBINPUT_POINTER_AXIS_SCROLL_HORIZONTAL;
>   	if (libinput_event_pointer_has_axis(event, axis)) {
> -		if (source == LIBINPUT_POINTER_AXIS_SOURCE_WHEEL)
> +		if (source == LIBINPUT_POINTER_AXIS_SOURCE_WHEEL) {
>   			value = libinput_event_pointer_get_axis_value_discrete(event, axis);
> -		else
> +			value *=  driver_data->scroll_hdist;
> +		} else {
>   			value = libinput_event_pointer_get_axis_value(event, axis);
> +		}
>   		valuator_mask_set_double(mask, 2, value);
>   	}
>
> @@ -1189,8 +1193,8 @@ xf86libinput_pre_init(InputDriverPtr drv,
>   	if (!driver_data->valuators)
>   		goto fail;
>
> -	driver_data->scroll_vdist = 1;
> -	driver_data->scroll_hdist = 1;
> +	driver_data->scroll_vdist = 15;
> +	driver_data->scroll_hdist = 15;
>
>   	path = xf86SetStrOption(pInfo->options, "Device", NULL);
>   	if (!path)
>