After fresh-installation of Loki, my AlpsPS/2 Dualpoint Touchpad has a bug. Whenever I place my finger on the Touchpad, the cursor 'jitters' or 'jumps.
The cursor also moves when my finger is almost 1 mm above the touchpad and has not yet touched it.
This bug also exists with synaptic touchpads.
The touchpad's sensitivity was very good in Freya but too high (almost unusable) in Loki.
============== Device Properties ==================
$ libinput-list-devices
--------------------------
Device: AlpsPS/2 ALPS DualPoint TouchPad
Kernel: /dev/input/event6
Group: 8
Seat: seat0, default
Size: 71.43x50.00mm
Capabilities: pointer
Tap-to-click: disabled
Tap-and-drag: enabled
Tap drag lock: disabled
Left-handed: disabled
Nat.scrolling: disabled
Middle emulation: n/a
Calibration: n/a
Scroll methods: *two-finger edge
Click methods: none
Disable-w-typing: enabled
Accel profiles: none
$ xinput list-props <device id>
---------------------------
Device 'AlpsPS/2 ALPS DualPoint TouchPad':
Device Enabled (152): 1
Coordinate Transformation Matrix (154): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
libinput Tapping Enabled (304): 1
libinput Tapping Enabled Default (305): 0
libinput Tapping Drag Enabled (306): 1
libinput Tapping Drag Enabled Default (307): 1
libinput Tapping Drag Lock Enabled (308): 0
libinput Tapping Drag Lock Enabled Default (309): 0
libinput Accel Speed (290): -0.256098
libinput Accel Speed Default (291): 0.000000
libinput Natural Scrolling Enabled (287): 1
libinput Natural Scrolling Enabled Default (288): 0
libinput Send Events Modes Available (271): 1, 1
libinput Send Events Mode Enabled (272): 0, 0
libinput Send Events Mode Enabled Default (273): 0, 0
libinput Left Handed Enabled (295): 0
libinput Left Handed Enabled Default (296): 0
libinput Scroll Methods Available (297): 1, 1, 0
libinput Scroll Method Enabled (298): 1, 0, 0
libinput Scroll Method Enabled Default (299): 1, 0, 0
libinput Disable While Typing Enabled (310): 1
libinput Disable While Typing Enabled Default (311): 1
Device Node (274): "/dev/input/event6"
Device Product ID (275): 2, 8
libinput Drag Lock Buttons (289): <no items>
libinput Horizonal Scroll Enabled (276): 1
Confirmed because the bug was reported by other people but it was misunderstood and marked as "Won't Fix" by Daniel Fore, but it is an important and annoying bug.
Please pay a little attention to the bug description before ignoring it.