Comment 16 for bug 727979

Upstream says something outside X is probably polling every 30 sec looking for monitors. This is unnecessary since the kernel automatically fires events when a monitor gets connected/disconnected.

Best guess is a daemon like upowerd or keventd is running. Look in `ps aux` to see if you have one of these running, and see if you shut it down or kill it if the bad behavior stops. If not, look for other daemons, services, or clients you might be running which could be polling for monitors and try killing them off one by one to narrow what is causing the issue for you.