path: root/doc
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authorPeter Hutterer <>2015-07-14 10:27:46 +1000
committerPeter Hutterer <>2015-07-27 19:34:42 +1000
commiteb146677eb5abb7951af4ead80874c992915b90d (patch)
tree536a96cbae712e899807d218fc927cbee8ff1fa7 /doc
parent316f30d2f28b62f90efc2bdd9e6f3d83116070e7 (diff)
touchpad: disable 2fg scrolling on Synaptics semi-mt touchpads
These touchpads have a terrible resolution when two fingers are down, causing scrolling to jump around a lot. That then turns into bug reports that we can't do much about, the data is simply garbage. Signed-off-by: Peter Hutterer <> Reviewed-by: Hans de Goede <>
Diffstat (limited to 'doc')
1 files changed, 7 insertions, 0 deletions
diff --git a/doc/scrolling.dox b/doc/scrolling.dox
index 658fe4b6..0c03c98d 100644
--- a/doc/scrolling.dox
+++ b/doc/scrolling.dox
@@ -44,6 +44,13 @@ movements will translate into tiny scroll movements.
Scrolling in both directions at once is possible by meeting the required
distance thresholds to enable each direction separately.
+Two-finger scrolling requires the touchpad to track both touch points with
+reasonable precision. Unfortunately, some so-called "semi-mt" touchpads can
+only track the bounding box of the two fingers rather than the actual
+position of each finger. In addition, that bounding box usually suffers from
+a low resolution, causing jumpy movement during two-finger scrolling.
+libinput does not provide two-finger scrolling on those touchpads.
@section edge_scrolling Edge scrolling
On some touchpads, edge scrolling is available, triggered by moving a single