This is especially a problem for the cursor tool which can be legitimately left on the tablet. It wobbles by a couple of device units, resulting in continuous axis updates to the caller. Pre-filter any of these events by the axis' fuzz value so we don't even process them.
For ABS_DISTANCE which doesn't have a fuzz we hard-code a minimum fuzz of 2. This should eventually land in the udev hwdb though. https://bugs.freedesktop.org/show_bug.cgi?id=94892 Signed-off-by: Peter Hutterer <peter.hutte...@who-t.net> --- src/evdev-tablet.c | 35 +++++++++++++++++++++++++++++++++++ src/evdev-tablet.h | 2 ++ 2 files changed, 37 insertions(+) diff --git a/src/evdev-tablet.c b/src/evdev-tablet.c index 84563a8..be828d9 100644 --- a/src/evdev-tablet.c +++ b/src/evdev-tablet.c @@ -112,6 +112,36 @@ tablet_device_has_axis(struct tablet_dispatch *tablet, return has_axis; } +static inline bool +tablet_filter_axis_fuzz(const struct tablet_dispatch *tablet, + const struct evdev_device *device, + const struct input_event *e, + enum libinput_tablet_tool_axis axis) +{ + int delta, fuzz; + int current, previous; + + previous = tablet->prev_value[axis]; + current = e->value; + delta = previous - current; + + fuzz = libevdev_get_abs_fuzz(device->evdev, e->code); + + /* ABS_DISTANCE doesn't have have fuzz set and causes continuous + * updates for the cursor/lens tools. Add a minimum fuzz of 2, same + * as the xf86-input-wacom driver + */ + switch (e->code) { + case ABS_DISTANCE: + fuzz = max(2, fuzz); + break; + default: + break; + } + + return abs(delta) <= fuzz; +} + static void tablet_process_absolute(struct tablet_dispatch *tablet, struct evdev_device *device, @@ -137,6 +167,11 @@ tablet_process_absolute(struct tablet_dispatch *tablet, break; } + tablet->prev_value[axis] = tablet->current_value[axis]; + if (tablet_filter_axis_fuzz(tablet, device, e, axis)) + break; + + tablet->current_value[axis] = e->value; set_bit(tablet->changed_axes, axis); tablet_set_status(tablet, TABLET_AXES_UPDATED); break; diff --git a/src/evdev-tablet.h b/src/evdev-tablet.h index 880d523..d12c675 100644 --- a/src/evdev-tablet.h +++ b/src/evdev-tablet.h @@ -55,6 +55,8 @@ struct tablet_dispatch { unsigned char changed_axes[NCHARS(LIBINPUT_TABLET_TOOL_AXIS_MAX + 1)]; struct tablet_axes axes; unsigned char axis_caps[NCHARS(LIBINPUT_TABLET_TOOL_AXIS_MAX + 1)]; + int current_value[LIBINPUT_TABLET_TOOL_AXIS_MAX + 1]; + int prev_value[LIBINPUT_TABLET_TOOL_AXIS_MAX + 1]; /* Only used for tablets that don't report serial numbers */ struct list tool_list; -- 2.5.5 _______________________________________________ wayland-devel mailing list wayland-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/wayland-devel
