xwayland: Clear scrolling fractional values after 2 secondsxwayland-1.12

Left over fractional values from previous scrolling could cause a tiny
new scroll axis amount to trigger a scroll button event.  We handle this
by tracking the time of the previous scroll event, and if the incoming
event is more than 2s later, we clear the fractional values.

2 files changed, 7 insertions, 0 deletions

diff --git a/hw/xfree86/xwayland/xwayland-input.c b/hw/xfree86/xwayland/xwayland-input.c
index d986deb54..c550d7743 100644
--- a/hw/xfree86/xwayland/xwayland-input.c
+++ b/hw/xfree86/xwayland/xwayland-input.c
@@ -377,6 +377,12 @@ pointer_handle_axis(void *data, struct wl_pointer *pointer,
     int i, val;
     const int divisor = 10;
 
+    if (time - xwl_seat->scroll_time > 2000) {
+	xwl_seat->vertical_scroll = 0;
+	xwl_seat->horizontal_scroll = 0;
+    }
+    xwl_seat->scroll_time = time;
+
     /* FIXME: Need to do proper smooth scrolling here! */
     switch (axis) {
     case WL_POINTER_AXIS_VERTICAL_SCROLL:
diff --git a/hw/xfree86/xwayland/xwayland-private.h b/hw/xfree86/xwayland/xwayland-private.h
index d595bc5d7..e4273166d 100644
--- a/hw/xfree86/xwayland/xwayland-private.h
+++ b/hw/xfree86/xwayland/xwayland-private.h
@@ -102,6 +102,7 @@ struct xwl_seat {
 
     wl_fixed_t			 horizontal_scroll;
     wl_fixed_t			 vertical_scroll;
+    uint32_t			 scroll_time;
 
     size_t			 keymap_size;
     char			*keymap;