well, after all I decided to update the kernel. it didn't happen again since the upgrade to 3.19
Linux Paula 3.19.0-32-generic #37~14.04.1-Ubuntu SMP Thu Oct 22 09:41:40 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1384342 Title: kernel messages intel_crtc_wait_for_pending_flips correlate to compiz hang To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1384342/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
