X Session killed when hibernate

Hi,
I'm using feisty fawn, 2 days ago I updated my system, since then when my notebook change to hibernate status the x session is killed and go to tty1.

I would like know how disabled hibernate feature in X and how retrieve more information about this problem. The log system (/var/log/syslog, /var/log/xlog.0, dmesg) not retrieve any message that can help me.

* If I click in Lock screen button (log off window), it happens the same problem.