According to this bug report, intel-virtual-output encounter some difficulties with xorg-server version 1.17.1:
david@david-ubuntu:~$ intel-virtual-output
XIO: fatal IO error 11 (Resource temporarily unavailable) on X server ":0"
after 20 requests (20 known processed) with 0 events remaining.
As reported by a user, downgrading to version 1.16 would solve the problem. How can I safely downgrade the xorg package?