relative mouse movement in games - cursor/view jumps to same position approximately every second

[Forrest Voight]

Distributor ID: Ubuntu
Description: Ubuntu maverick (development branch)
Release: 10.10
Codename: maverick

After an update on 2010-07-14, relative mouse movement in two SDL-based games broke. Also, a clean install on a separate computer has the same problem.

Slightly more often than every second, the view angles in an FPS interface/the cursor jumps back to the same spot while using relative mouse movement.

This is not a bug in libsdl1.2 because with it downgraded the problem still exists.

[Forrest Voight (forrestv)]

Steps to reproduce
apt-get install tremulous
tremulous
# try to use main menu

[Dave Gilbert (ubuntu-treblig)]

Yeh, I've seen this in Assaultcube.

[Forrest Voight (forrestv)]

SDL_MOUSE_RELATIVE=0 prevents the problem but changes the behaviour - the real cursor is never repositioned so it it runs into the edge of the screen you can't move.

Since the problem isn't in libsdl1.2, something in xorg-server having to do with how client mouse repositioning is handled must have changed. The upgrade that caused this problem contained xorg-server-core (1.8.1.902-0ubuntu1, 1.8.1.902-0ubuntu2).

[Forrest Voight (forrestv)]

Oh, this is a duplicate of https://bugs.launchpad.net/ubuntu/+bug/61105 , but it's notable that an update caused unclutter to be installed. http://im.forre.st/pb/19520546.txt

'killall unclutter' fixes this.