Mouse cursor movements are jaggy

[Wolf Rogner]

Ever since the update to 3.1.6 (on 8.9.2017) the mouse jumps around the screen and does not follow a smooth trail.

As this was the only update that is related to position calculation I suspect the library to be the cause of this issue.

A similar issue has been reported under #1716022

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: libmpfr4 3.1.6-1
ProcVersionSignature: Ubuntu 4.12.0-13.14-generic 4.12.10
Uname: Linux 4.12.0-13-generic x86_64
ApportVersion: 2.20.7-0ubuntu1
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Fri Sep 8 19:32:57 2017
Dependencies:
 gcc-7-base 7.2.0-4ubuntu1
 libc6 2.26-0ubuntu1
 libgcc1 1:7.2.0-4ubuntu1
 libgmp10 2:6.1.2+dfsg-1
InstallationDate: Installed on 2017-09-05 (3 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Alpha amd64 (20170902)
SourcePackage: mpfr4
UpgradeStatus: No upgrade log present (probably fresh install)

[Wolf Rogner (war-rsb)]

Played around with magnification.
Pressing Super-Alt-8 somehow creates this situation.

Increasing the magnification to 200%, pressing Super-Alt-8 and reverting to 100% remedies the effect.

Thus: An issue that I cannot explain.

[Vincent Lefevre (vincent-vinc17-net)]

I assume that the mouse is handled by Xorg, which does not use MPFR. So I don't see how this could be related. This is just a coincidence, and the cause of the problem is somewhere else. This bug should be closed as invalid.

[Wolf Rogner (war-rsb)]

In 17.10 there is no Xorg by default. 17.10 runs under Wayland.

There was a key combination to switch to magnified display. Setting a fixed resolution does not change the visuals but the coordinate system of the mouse. After figuring out about the magnification and resetting it, the mouse worked fine.

=> Can be closed.