[Nouveau] Artifacts on external monitor with Optimus and GK107 on Thinkpad W530

[Nicolas Göddel]

Hi there,

last week I installed Ubuntu Gnome 14.04 on my Thinkpad W530. It has the
following specifications:

Intel Core i7-3820QM
Intel HD 4000 and nVidia Quadro K2000M
15,6" FHD RGB 1920x1080

With "Optimus" enabled in the BIOS, I am able to use the external monitor via
VGA-1-2. But there are refresh problems only on the external monitor: Mouse
traces, parts of a window remain on the screen after closing the window, etc. My
idea was to enable VSync for the external monitor but I don't know how to enable
this. If you say enabling VSync will not help, maybe you have an other idea to
avoid these refresh problems?

This is what 'glxgears' outputs (First 8 lines the glxgears window was on the
external screen, last 3 lines the window was on the internal screen):

nicolas at tp-w530:~$ glxgears
Running synchronized to the vertical refresh. The framerate should be
approximately the same as the monitor refresh rate.
14814 frames in 5.0 seconds = 2962.673 FPS
16443 frames in 5.0 seconds = 3288.454 FPS
15912 frames in 5.0 seconds = 3182.394 FPS
14498 frames in 5.0 seconds = 2898.920 FPS
13834 frames in 5.0 seconds = 2766.738 FPS
14584 frames in 5.0 seconds = 2916.712 FPS
14802 frames in 5.0 seconds = 2960.245 FPS
11026 frames in 5.0 seconds = 2205.070 FPS
299 frames in 5.0 seconds = 59.675 FPS
299 frames in 5.0 seconds = 59.680 FPS
299 frames in 5.0 seconds = 59.676 FPS

This is how I tested VSync.

Best Regards,
Nicolas