Ubuntu
kde-workspace package

  1. Bug #1267977
  2. Comment #5

Comment 5 for bug 1267977

Revision history for this message
In , Michael Marley (mamarley) wrote :

On my Kubuntu 14.04 (Trusty) system with an Nvidia graphics card and version 331.20 of the binary driver, I began having a problem with very jerky/juddery graphics after updating from kde-workspace 4.11.4 to 4.11.5. (The rest of the system is on 4.12.) About every half-second or so, everything moving or animating on the screen jerks very noticeably. This occurs for both OpenGL things like glxgears and for 2D things like scrolling in Firefox.

Looking through the changelog for 4.11.5, it would seem that the issue probably would have been caused by this: https://git.reviewboard.kde.org/r/114162/. However, using the KWIN_USE_BUFFER_AGE=0 environment variable does not eliminate the jerkiness. It does, however, introduce tearing, unless I set "Tearing Prevention (VSync)" to "Full Scene Repaints."

Reproducible: Always

Steps to Reproduce:
1. Get a system with an Nvidia graphics card and install a GLX_EXT_BUFFER_AGE-supporting driver version.
2. Install/upgrade to kwin 4.11.5.
3. Launch glxgears
Actual Results:
glxgears should run smoothly without dropping any frames.

Expected Results:
glxgears jerks noticeably about twice every second.