Moving windows between workspaces causes them to "jitter" / jump around

Bug #876575 reported by nimu on 2011-10-17
This bug affects 4 people
Affects Status Importance Assigned to Milestone
Compiz Core
Daniel van Vugt
compiz (Ubuntu)

Bug Description

This bug occurs in combination with window snapping

- Drag any window to the right or left side of the current workspace to make it snap at either side (fill one half of the desktop)
- activate expo mode
- try to drag the window to a different workspace
- See what happens: The mouse and the window start jumping around very fast.

This also seems to happen when moving windows between workspaces with Shift+Ctrl+Alt+<arrow-key>.


In ccsm, go to General > OpenGL and disable "Sync To VBlank".
(To install ccsm you need to install the package "compizconfig-settings-manager")

Related branches

cmat (cmat555) wrote :

Seems like the latest patches fixed this problem for me.

Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Sebastien Bacher (seb128) wrote :

nimu, is that fixed for you as well?

Changed in compiz (Ubuntu):
status: New → Confirmed
affects: unity (Ubuntu) → compiz (Ubuntu)
Changed in compiz (Ubuntu):
importance: Undecided → Low
affects: unity → compiz
Changed in compiz:
importance: Undecided → Low
Daniel van Vugt (vanvugt) wrote :

I can't reproduce the issue with the above instructions, but I can reproduce the problem by moving windows with Shift+Ctrl+Alt+<arrow-key>. And the problem is solved for me using this proposed fix:

@nimu, please clarify if that is the same "jitter" problem as you originally described.

Changed in compiz:
assignee: nobody → Daniel van Vugt (vanvugt)
status: New → Incomplete
Changed in compiz (Ubuntu):
assignee: nobody → Daniel van Vugt (vanvugt)
status: New → Incomplete
Changed in compiz:
status: Incomplete → Confirmed
Changed in compiz (Ubuntu):
status: Incomplete → Confirmed
Daniel van Vugt (vanvugt) wrote :

Confirmed... I will assume I have the same bug unless proven otherwise.

description: updated
description: updated
Daniel van Vugt (vanvugt) wrote :

Experimental fixes for this and related performance bugs are now available
for testing in ppa:vanvugt/compiz and ppa:vanvugt/unity. For the best
results I recommend trying both together. But testing them individually is
useful too.


  * The fixes in ppa:vanvugt/compiz REQUIRE that "Sync To VBlank" is ENABLED
    in CompizConfig Settings Manager (OpenGL section).
    This is the default setting when Ubuntu 11.10 is installed.

  * When using ppa:vanvugt/compiz you should DISABLE the workaround
    "Force full screen redraws (buffer swap) on repaint" in
    CompizConfig Settings Manager (Workarounds section).
    This is the default setting when Ubuntu 11.10 is installed.

  * I don't claim to have fixed all tearing. I only claim that the amount of
    tearing in oneiric with the fix is no longer worse than in natty.

  * nouveau: If you are using the "nouveau" driver for NVIDIA chips you will
    need to enable sync-to-vblank support in the driver options because
    nouveau has it disabled by default. You can do this by editing
    /etc/X11/xorg.conf and adding:
       Section "Device"
           Identifier "My Graphics"
           Option "GLXVBlank" "on"
    Then log out and in again for it to take effect.

  * fglrx (Catalyst): The fglrx driver also disables sync-to-vBlank support
    by default. To fix this:
      1. Open Catalyst Control Center.
      2. Go to 3D > More Settings.
      3. Set "Wait for vertical refresh" to
         "On, unless application specifies".

  * Please don't try using the Benchmark plugin in compiz-plugins-extra
    because it is broken and misleading (bug 898548).

Please leave feedback in the relevant bug reports.

- Daniel


ppa:vanvugt/compiz |
compiz (1:0.9.6+bzr20110929-0ubuntu6vv2) oneiric

  * Added proposed fix for inaccurate frame timing causing tearing and
    (LP: #880707) (LP: #888039) (LP: #92599) (LP: #798868) (LP: #876575)

ppa:vanvugt/unity |
unity (4.24.0-0ubuntu2b1vv4) oneiric; urgency=low

  * Fix major performance regressions due to unnecessary UnityFBO binding
    (LP: #861061) (LP: #880707)
    UnityFBO was being bound even when not required. This caused major lag in
    glPaintOutput, which slowed down all rendering. This was seen in reduced
    framerates in apps (LP: #861061) and significantly worse screen tearing
    with Unity 4.x compared to 3.x (LP: #880707).

affects: compiz → compiz-core
Changed in compiz-core:
status: Confirmed → In Progress
Changed in compiz (Ubuntu):
status: Confirmed → In Progress
Daniel van Vugt (vanvugt) wrote :

Attached a new branch, which smspillaz says should fix the root cause of this bug too.

Changed in compiz (Ubuntu):
assignee: Daniel van Vugt (vanvugt) → nobody
status: In Progress → Confirmed
tags: added: performance
Changed in compiz-core:
status: In Progress → Fix Committed
Changed in compiz-core:
milestone: none → 0.9.7
Daniel van Vugt (vanvugt) wrote :

Fix released in:
compiz (1: precise; urgency=low

Changed in compiz (Ubuntu):
status: Confirmed → Fix Released
Changed in compiz-core:
status: Fix Committed → Fix Released
Changed in ubutter:
status: New → Fix Released
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