Package: xserver-xorg-video-openchrome Version: 1:0.2.903+svn741-1 Severity: importantI downgraded to the version of testing and everything works fine. I will let it on hold until a new version arrives.
Do you need further informations for localising the error.I did not change anything related to the resolution or to the options in the xorg.conf.
Greetings