Bug 1492643

What's the output of "xinput list-props <device name>" please? Does it still show the Synaptics driver properties? And if you run syndaemon manually, does it stop jumping?

$ xinput list-props "SynPS/2 Synaptics TouchPad"
Device 'SynPS/2 Synaptics TouchPad':
	Device Enabled (138):	1
	Coordinate Transformation Matrix (140):	1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
	Device Accel Profile (268):	1
	Device Accel Constant Deceleration (269):	2.500000
	Device Accel Adaptive Deceleration (270):	1.000000
	Device Accel Velocity Scaling (271):	12.500000
	Synaptics Edges (272):	1310, 4826, 2220, 4636
	Synaptics Finger (273):	25, 30, 0
	Synaptics Tap Time (274):	180
	Synaptics Tap Move (275):	218
	Synaptics Tap Durations (276):	180, 180, 100
	Synaptics ClickPad (277):	1
	Synaptics Middle Button Timeout (278):	0
	Synaptics Two-Finger Pressure (279):	282
	Synaptics Two-Finger Width (280):	7
	Synaptics Scrolling Distance (281):	99, 99
	Synaptics Edge Scrolling (282):	0, 0, 0
	Synaptics Two-Finger Scrolling (283):	1, 1
	Synaptics Move Speed (284):	1.000000, 1.750000, 0.040331, 0.000000
	Synaptics Off (285):	0
	Synaptics Locked Drags (286):	0
	Synaptics Locked Drags Timeout (287):	5000
	Synaptics Tap Action (288):	0, 0, 0, 0, 1, 3, 2
	Synaptics Click Action (289):	1, 3, 2
	Synaptics Circular Scrolling (290):	0
	Synaptics Circular Scrolling Distance (291):	0.100000
	Synaptics Circular Scrolling Trigger (292):	0
	Synaptics Circular Pad (293):	0
	Synaptics Palm Detection (294):	0
	Synaptics Palm Dimensions (295):	10, 200
	Synaptics Coasting Speed (296):	20.000000, 50.000000
	Synaptics Pressure Motion (297):	30, 160
	Synaptics Pressure Motion Factor (298):	1.000000, 1.000000
	Synaptics Grab Event Device (299):	0
	Synaptics Gestures (300):	1
	Synaptics Capabilities (301):	1, 0, 0, 1, 1, 1, 1
	Synaptics Pad Resolution (302):	42, 42
	Synaptics Area (303):	0, 0, 2600, 0
	Synaptics Soft Button Areas (304):	3681, 0, 0, 2600, 2454, 3681, 0, 2600
	Synaptics Secondary Soft Button Areas (305):	3395, 0, 0, 2445, 2740, 3395, 0, 2445
	Synaptics Noise Cancellation (306):	30, 30
	Device Product ID (262):	2, 7
	Device Node (263):	"/dev/input/event5"


That's a thinkpad t440s.

Running syndaemon directly make my touchpad stop working. Then if I used the trackpoint, it work again for a while and stop working once I stop moving the cursor after something like 5 second. Then the touchpad no longer react until I move the mouse cursor again with the trackpoint.

I just had the issue while I was typing, and stopped immediately to verify if my finger touched anything, but no, I didn't seems in contact with the touchpad.

Attached are the log of the last jump, (occur 3 minutes after the start of the record)

Created attachment 1328340 [details]
Log from the last jump

So, running syndaemon did wrock havoc, I had to go in gnome control center and disable and reenable touchpad to make it work again.

syndaemon is supposed to be run by the desktop environment. This used to be part of gnome-settings-daemon but something went wrong in the 7.4 rebase, see bug 1478397

my tests with running syndaemon manually though were successful so far, I haven't reproduced the issue you've been seeing yet. it's worth running

xinput watch-props  "SynPS/2 Synaptics TouchPad" in a terminal window and starting syndaemon as "syndaemon -v". syndaemon will print Disable/Enable whenever it does that on the touchpad and you should see the Synaptics Off property toggling accordingly. If that works, that's at least a start and we can figure out the rest from there.

This should get fixed in 7.5 via bug 1478397

Closing as duplicate because that's the easiest way, this isn't a synaptics bug but rather an issue resulting from the gnome rebase.

*** This bug has been marked as a duplicate of bug 1478397 ***