Ubuntu 14.04 is installed on by Dell Latitude E7440, with Intel Driver and external displays connected using a Dell Port Replicator.
Beginning 4 or 5 weeks ago, Ubuntu starts to randomly "freeze". With "freeze" I mean the following:
- All displays still show the same picture, but nothing gets refreshed.
- This time, a movie was running in VLC. The sound was still going on, display was frozen
- The mouse still can be moved, is however locked to one display.
- Nothing can be clicked or modified
- Changing VTY using Ctrl+Alt+F1 does not change the state of the external displays, they still keep showing the picture they have shown before Ubuntu crashed. The "internal" display goes black, no command line login appears. Change back to VTY7 does not affect the system state in any kind
The only way to resolve this issue is to hard-reset the system using the power button. Then everything is fine again. I tried to eliminate several things. I removed Wallch, VirtualBox and VLC where only running at some occurrences.
For me, it sounds like a hardware or driver failure, however, I was not able to find any problem here. I ran full system diagnostics (DELL diagnostics) as well as a full RAM check - without errors.
Syslog does not show anything. Last entry is:
May 11 21:09:27 pc2183 wpa_supplicant: wlan0: WPA: Group rekeying completed with 24:65:11:b8:a6:26 [GTK=TKIP]
The next entry already shows the restarting system, initializing syslogd.
As the problem seems to be persistent (it happens randomly, but often, say twice a day), rebooting all over again is not my preferred solution.
What could be the issue of this problem? Where can I find further information?