This is not a GDM bug. This is most likely a xorg or video driver problem. Please attach your /var/log/Xorg.0.log and /var/log/Xorg.0.log.old after you experience this problem.
This is not a GDM bug. This is most likely a xorg or video driver problem. Please attach your /var/log/Xorg.0.log and /var/log/ Xorg.0. log.old after you experience this problem.